Get documents about "TOPIC Electrocardiogram
Document Sample
Community College of Baltimore County
Catonsville Campus
Notes and Objectives
Ms. J. Ellen Lathrop-Davis, M. Sc.
Dr. Ewa Gorski, Ph. D.
Mr. Stephen Kabrhel, M. Sc.
Introduction
BIOL 221 Anatomy & Physiology II is a continuation of BIOL 220 Anatomy &
Physiology I. As such, it builds on the concepts first learned in A&P I. You are expected to
have successfully completed A&P I (C or better from CCBC or equivalent course from an
accredited college or university). In most cases, information covered in A&P I will be
utilized without being reviewed in A&P II. It is YOUR responsibility to make sure that you
understand the material from A&P I. Selected review topics from A&P I are listed in the
Appendix at the end of this lecture supplement. This list merely suggests the most
important review topics and is not all-inclusive.
PowerPoint presentations given in class are available through the A&P II web page.
Objectives for each topic available through the A&P II web page include live links to other
relevant web pages. Web pages for your instructor can be accessed from the main A&P
web page. Check your instructor’s page for additional resources.
Good luck and have a great semester!
J. Ellen Lathrop-Davis
Assistant Professor, Biology
BIOL221 Coordinator
Contents
Topic 1 Circulatory System: Blood .................................................................................................................... p. 1
Topic 2 Circulatory System: Heart ................................................................................................................ p. 17
Topic 3 Circulatory System: Blood Vessels .............................................................................................. p. 35
Topic 4 Circulatory System: Blood Flow, Blood Pressure, and Capillary Dynamics.......... p. 43
Topic 5 Lymphatic System .................................................................................................................................. p. 59
Topic 6 Immune System – Resistance to Disease ................................................................................ p. 65
Topic 7 Respiratory System ............................................................................................................................... p. 81
Topic 8 Digestive System...................................................................................................................................p. 101
Topic 9 Nutrition, Metabolism and Thermoregulation .................................................................... p. 129
Topic 10 Urinary System.......................................................................................................................................p. 141
Topic 11 Fluid, Electrolyte and Acid-base Balance.............................................................................. p. 157
Topic 12 Reproductive System ..........................................................................................................................p. 171
Topic 13 Survey of Development......................................................................................................................p. 181
Appendix Review Topics from A&P I ............................................................................................................ p. 189
A&P Main Page: http://student.ccbc.cc.md.us/c_anatomy/index.html
A&P II Page: http://student.ccbc.cc.md.us/c_anatomy/ap2web/AP2index.htm
E. Lathrop-Davis / E. Gorski / S. Kabr hel i BIOL221: Anatomy & Physiology II
E. Lathrop-Davis / E. Gorski / S. Kabr hel ii BIOL221: Anatomy & Physiology II
TOPIC 1
Circulatory System – Blood
Ch. 18, pp. 651-677
Objectives
Introduction
1. List the major components of the circulatory system.
2. List and describe the major functions of the circulatory system.
Characteristics and Functions of Blood
1. Describe the main physical characteristics of blood.
2. Categorize blood as one of the 4 main types of tissue; defend your answer.
3. List and describe the functions of blood in the body.
4. Define and describe plasma and serum.
5. List the major types of proteins found in plasma and describe their functions.
Erythrocytes
1. Describe the structure and function of erythrocytes.
2. Relate the structure of erythrocytes to their function in transportation of respiratory
gases.
3. Describe the structure and function of hemoglobin.
4. Describe the formation and degradation of erythrocytes.
5. Describe the methods of measuring/estimating erythrocyte abundance and estimating
production using reticulocyte counts and explain their clinical importance.
6. Describe the methods for assessing the blood’s ability to carry oxygen and explain
their clinical importance.
7. Discuss the pros and cons of blood doping.
8. Explain the basis and importance of blood typing.
9. Describe ABO and Rh blood typing and the basis and significance of cross-reactions.
Leukocytes
1. List the type of leukocytes in order of their normal relative abundance and describe
the structural features of each.
2. Differentiate between granulocytes and agranulocytes.
3. Describe the process and regulation of white blood cell formation.
4. Discuss the role of leukocytes in phagocytosis and antibody production.
5. Explain the process and significance of white blood cell and differential white blood
cell counts.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 1 Circulatory System: Blood
Hemostasis
1. List and describe the three mechanisms (“phases”) by which the body limits bleeding.
2. Discuss the structure and formation of platelets.
3. Describe the role of platelets in platelet plug formation and coagulation.
4. Describe the stages of platelet plug formation.
5. Describe the regulation of platelet plug formation including stimulation and limitation.
6. Define and differentiate between the intrinsic and extrinsic pathways of blood
coagulation.
7. Describe the major stages of the intrinsic and extrinsic pathways of blood coagulation.
8. List the factors that promote or inhibit coagulation.
9. Explain the roles of vitamin K and calcium ions in coagulation.
10. Discuss how the body controls clotting.
11. Discuss the clinical use of heparin, aspirin and coumadin.
12. Define clotting time and bleeding time.
13. Discuss clot retraction and fibrinolysis.
Disorders
1. Describe the following disorders of blood.
a. Anemias (Sickle cell anemia; Hemorrhagic anemia; Iron-deficiency anemia;
Pernicious anemia)
b. Thalassemia
c. Jaundice
d. Erythroblastosis fetalis
e. Mononucleosis
f. Polycythemia
g. Neutrophilia
h. Eosinophilia
i. Thrombocytopenia
j. Thrombocytosis
k. Acute leukemia
l. Chronic leukemia
m. Thrombosis
n. Embolism
o. Infarct (stroke, myocardial infarct)
p. Hemophilia
q. Von Willebrand disease
2. Relate the effects of sickle cell anemia and thalassemia to the structure of
erythrocytes.
3. Compare and contrast the causes of iron-deficiency anemia, pernicious anemia and
E. Lathrop-Davis / E. Gorski / S. Kabr hel 2 Circulatory System: Blood
Topic 1: Circulatory System – Blood
I. Major Components of the Circulatory System Fig. 20.2, p. 720
A. Blood
B. Heart
C. Blood vessels
II. Major Functions of the Circulatory System
A. Transportation
B. Protection
1. Against disease and toxins
2. Against blood loss
C. Regulation
1. Blood pressure
2. Blood volume
3. Body temperature
*Most functions are most directly accomplished by blood
III. Blood
A. Physical Characteristics
1. Specific gravity = 1.045-1.065
2. Viscosity = 4.5-5.5
3. pH = 7.35 – 7.45
4. Volume = 7-9% of body weight
a. 5-6 L in males
b. 4-5 L in females
5. Temperature = 100.4 oF (38 oC)
B. Connective tissue: Fig. 18.1, p. 651
1. Cells & cell fragments = “formed elements”
a. erythrocytes = RBCs (99.9%) – carry O2 and CO2
b. leukocytes = WBCs – fight disease
c. thrombocytes = platelets (cell fragments) - hemostasis
2. Matrix (plasma)
a. ground substance (serum)
b. plasma proteins
E. Lathrop-Davis / E. Gorski / S. Kabr hel 3 Circulatory System: Blood
C. Plasma: definition and composition
1. Definitions
a. Plasma = whole blood minus cells
b. Serum = plasma without protein clotting factors
2. Constituents
a. 92% water
b. 7% plasma proteins
c. 1% other solutes (including inorganic ions [electrolytes],
organic nutrients and wastes, respiratory gases)
D. Plasma proteins
1. Most made by liver
2. Albumins (~ 60%)
a. exert osmotic force
b. buffer pH
3. Globulins (~ 35%)
a. immunoglobulins (antibodies) – protect against disease
b. transport proteins (e.g., transferring) - bind ions and
small molecules
4. Fibrinogen (~ 4% of all plasma proteins) – soluble protein
essential to clotting
5. Other plasma proteins:
a. hormones (e.g., insulin, glucagon)
b. clotting factors (prothrombin)
c. enzymes (e.g., renin)
d. proenzymes (e.g., several proteins involved in clotting)
E. Erythrocytes (RBCs)
1. Functions
a. transport of respiratory gases
Transports about 98.5% of O2 (oxyhemoglobin); about
23% of CO2 (carbaminohemoglobin)
b. Aids conversion of CO2 to bicarbonate (HCO3 -)
2. Characteristics Fig. 18.3, p. 654
a. Small, biconcave disk
b. Anucleate, no ribosomes
c. No mitochondria
E. Lathrop-Davis / E. Gorski / S. Kabr hel 4 Circulatory System: Blood
d. Average diameter = 7-8 micrometers (μm)
e. Mean corpuscular volume (MCV)
1) microcytic
2) macrocytic
f. Life span ~ 120 days (or less)
3. Measuring abundance
a. Normally, RBCs account for 99.9% of all formed
elements
b. Red blood cell count
1) males: 4.5-6.3 x 106 / mm3 (microliter)
2) females: 4.2-5.5 x 106 / mm3
3) polycythemia
c. Hematocrit – packed cell volume (PCV)
1) males: average 45 (range: 40-54%)
2) females: average 42% (range 37-47%)
3) minimum hematocrit to donate blood = 38%
4) “buffy coat”
5) blood doping
4. Hemoglobin (Hb) Fig. 18.4, p. 655
a. Accounts for > 95% of protein in RBC
b. Main functions:
1) O2 transport
2) CO2 transport
3) aids blood pressure regulation
c. Globular protein with quaternary structure: 2 alpha
chains & 2 beta chains
d. Heme
1) non-protein, lipid-like structure
2) porphyrin ring with iron center (binds oxygen)
3) 4 heme per hemoglobin (one per chain)
e. Hemoglobin content of blood
1) measured as g of hemoglobin /dl of blood (grams per
deciliter, or 100 ml)
i. male: 14-18 g/dl (g/100 ml)
ii. female: 12-16 g/dl
iii. infants: 14-20 g/dl
E. Lathrop-Davis / E. Gorski / S. Kabr hel 5 Circulatory System: Blood
2) mean corpuscular Hb (hemoglobin
concentration/number of RBCs)
i. normochromic
ii. hypochromic
iii. hyperchromic
5. Location of erythrocyte formation (erythropoiesis)
a. 1st 8 weeks of fetal development, RBCs formed in yolk
sac
b. 2nd to 5th months fetal development, RBCs formed in
liver (main supplier), spleen, thymus (WBCs), bone
marrow (begins in bone marrow during 5th month)
c. Post-natal development and in adults, formed in red
bone marrow (myeloid tissue)
1) portions of vertebrae, ribs, scapula, skull, pelvis,
proximal heads of femur and humerus
2) yellow marrow can be converted into red marrow, if
needed
6. Stages of erythropoiesis Fig. 18.5, p. 656
a. Hemocytoblasts
b. Proerythroblasts
c. Erythroblasts
d. Normoblasts
e. Reticulocyte
1) contains ribosomes and mitochondria Hb synthesis
continues
2) leaves bone marrow after 2 days
3) reticulocyte count: normally ~ 0.8% of RBC
population (0.8-2.0%)
f. Mature RBC
7. Control of erythropoiesis – under influence of
erythropoietin
a. Erythropoietin secreted by kidney under hypoxic
conditions:
1) anemia
2) decreased blood flow to kidney
3) decreased oxygen availability
E. Lathrop-Davis / E. Gorski / S. Kabr hel 6 Circulatory System: Blood
b. Erythropoietin stimulates:
1) increased cell division of stem cells and
erythroblasts
2) increased maturation by increasing rate of Hb
synthesis
3) negative feedback control Fig. 18.6, p. 657
c. Other factors influencing rate of erythropoiesis
1) indirectly stimulated by thyroxine, androgens,
growth hormone
2) adequate diet
i. amino acids
ii. vitamins (B1 2 , B6 , folic acid)
(a) pernicious anemia
iii. iron (Fe)
(a) iron-deficiency anemia
8. Erythrocyte recycling
a. 10% hemolyzed
b. 90% phagocytized by macrophages in spleen, liver, bone
marrow
1) amino acids released into blood
2) heme broken into Fe and heme
i. Fe transported as transferrin to red bone
marrow for reincorporation into Hb or to liver or
spleen for storage as ferritin or hemosiderin
ii. porphyrin ring converted to biliverdin bilirubin
(or other forms)
(a) excreted in bile and released in feces
(b) excreted in urine
(c) jaundice
(i) liver dysfunction
(ii) excessive rupture of RBCs
(iii) obstruction of bile passageways
E. Lathrop-Davis / E. Gorski / S. Kabr hel 7 Circulatory System: Blood
9. Blood typing
a. Based on surface antigens (integral glycoproteins)
b. At least 50 kinds of proteins used
c. Most common
1) ABO blood group Fig. 18.15, p. 675
2) Rh factor (D)
d. Cross reactions
1) agglutination
2) erythroblastosis fetalis
i. Rhogam
ABO blood types
(see also Table 18.4 p. 673)
Blood Type A B AB1 O2
Agglutinogens A B A&B (neither)
(antigen proteins)
Present
Makes Agglutinins B A (neither) A&B
(antibodies) Against
May Receive Blood A, O B, O A, B, AB, O O
From:
May Give Blood To: A, AB B, AB AB A, B, AB, O
Genotype A A
I I or I Ai B B
I I or IBi IAIB ii
Rh Factor Present or Present or Present or Present or
Absent Absent Absent Absent
(A+ or A-) (B+ or B-) (AB+ or AB-) (O+ or O-)
1
Universal Recipient
2
Universal Donor
E. Lathrop-Davis / E. Gorski / S. Kabr hel 8 Circulatory System: Blood
Rhesus (Rh) Factor
Blood Type Rh+ Rh-
Agglutinogen D (antigen proteins) Present Absent
Present or Absent
Makes Agglutinins (antibodies) Against No Yes3
Agglutinogen
May Receive Blood From: Rh+ or Rh- Rh- 4
May Give Blood To Without Reaction4 : Rh+ Rh+ or Rh-
Genotype DD or Dd dd
10. RBC and associated disorders
a. Thalassemia – genetic inability to produce adequate
amounts of alpha or beta chains; results in limited
production of fragile, short-lived RBCs
b. Sickle-cell anemia – genetic mutation in which 7th amino
acid in beta chain is changed; causes Hb molecules to
stick when oxygen is not bound leading to
characteristic sickle shape of RBCs
c. Other anemias
1) iron-deficiency anemia
2) pernicious anemia
3) hemorrhagic anemia
d. Hemoglobinuria
F. Leukocytes
1. Functions:
a. fight pathogens (provide innate and adaptive
resistance)
b. clear debris
c. fight cancer
3
Only makes antibodies (agglutinens) after exposure to Rh+ blood cells (via transfusion or during birth
process)
4
Transfusion of Rh- individual with Rh+ blood results in production of anti -D agglutinens; sensitizes person
to Rh factor and may result in anaphylaxis if exposed a second time. Erythroblastosis fetalis arises when Rh-
mother has been exposed to Rh+ blood and is carrying Rh+ child.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 9 Circulatory System: Blood
2. Normal abundance – 5,000-10,000 cells / mm3
a. Leukopenia (< 5,000 cells/mm3 )
b. Leukocytosis (>10,000 cells/mm3 )
1) normal with disease
2) 100,000 WBCs / mm3 not uncommon with certain
types of leukemia
3. Differential WBC count
a. Relative abundance of different kinds of WBCs
b. Accomplished by counting number of each different
type in a total of 100 WBCs
4. Types
a. Granulocytes
1) neutrophils: 40-70%
i. phagocytic, especially against bacteria; large
number of lysosomes in cytoplasm; highly mobile
ii. 10-14 um in diameter
iii. short life spans (~ 10 hrs; less if highly active)
iv. neutrophilia
2) eosinophils: 2-4%
i. 10-14 μm in diameter
ii. phagocytize antibody-covered objects (bacteria,
cellular debris, parasitic worms and protozoa);
also respond during allergic reactions; release
nitric oxide and cytotoxic enzymes onto target
particles
iii. eosinophilia
3) basophils: < 1%
i. 10-12 μm in diameter
ii. accumulate in damaged tissues where they
release histamine and heparin
iii. basophilia
b. Agranulocytes
1) lymphocytes: 20-30%
i. 5-17 μm in diameter
ii. most remain in lymphatic tissue
E. Lathrop-Davis / E. Gorski / S. Kabr hel 10 Circulatory System: Blood
iii. 3 classes of circulating lymphocytes
(a) T cells
(b) B cells
(c) natural killer (NK) cells
iv. increase associated with a number of infections,
especially viral
2) monocytes: 2-8%
i. 14-24 μm in diameter
ii. become fixed or wandering macrophages within
tissues
iii. phagocytize viruses, debris, bacteria; enhance
scar tissue formation
3) mononucleosis
c. Lymphocyte production & regulation Fig. 18.11, p. 665
1) arise from hemocytoblasts
i. lymphoid stem cells lymphoblasts
prolymphocytes lymphocytes
ii. myeloid stem cells
(a) monoblast promonocyte monocytes
macrophages
(b) myeloblast myelocytes granulocytes
2) regulation of leukocyte production
i. thymic hormones promote differentiation and
maintenance of T cells
ii. presence of antigens stimulates lymphocyte
production
iii. cytokines
(a) colony stimulating factors (CSFs)
(i) stimulate development of WBCs
(ii) named for the type(s) of WBCs
(b) interleukins
3) leukemia
i. acute leukemia
ii. chronic leukemia
E. Lathrop-Davis / E. Gorski / S. Kabr hel 11 Circulatory System: Blood
G. Platelets
1. Characteristics and abundance
a. Small (2-4 μm in diameter), anucleate cell fragments
b. Short-lived (5-10 days)
c. Abundance: 250,000–500,000 platelets / mm3 of plasma
1) thrombocytopenia
i. excess platelet destruction
ii. inadequate production
iii. symptoms include bleeding in digestive tract,
skin, CNS
2) thrombocytosis
i. infection
ii. inflammation
iii. cancer
2. Platelet functions, formation and regulation
a. Functions:
1) platelet plug formation
2) enhance clotting
3) clot retraction
b. Formation: hemocytoblasts megakaryocyte
platelet Fig. 18.12, p. 667
c. Regulation
1) thrombopoietin (TPO or thrombocyte-stimulating
factor)
2) interleukin-6 (IL-6)
3) multi-CSF
IV. Hemostasis
A. Vascular Phase
1. Vascular spasm – contraction of smooth muscle of vessel
wall
2. Endothelial cells
a. Contract and pull vessel walls closer together
b. Endothelial cells release of chemical factors and local
hormones that stimulate vascular spasm & division of
endothelial cells, smooth muscle cells and fibroblasts
E. Lathrop-Davis / E. Gorski / S. Kabr hel 12 Circulatory System: Blood
c. In capillaries, endothelial cells on opposite sides
become sticky and adhere to each other to close vessel
B. Platelet Phase – Platelet Plug Formation
1. Stages
a. platelet adhesion
b. platelet aggregation
2. Activated platelets release:
a. ADP
b. thromboxane A2 & serotonin
c. protein clotting factors
d. platelet-derived growth factor
e. calcium ions
3. Limits to platelet plug formation
a. prostacyclin
1) released by endothelial cells
2) inhibits platelet aggregation
b. inhibitory compounds secreted by WBCs
c. circulating enzymes that degrade ADP
d. other inhibitory compounds (e.g., serotonin blocks
action of ADP)
e. clotting
C. Coagulation (clotting) Phase
1. Series of reactions (reactions cascades) resulting in
formation of insoluble fibrin fibers
2. Positive feedback loop in which thrombin (produced near
end of reaction sequence) stimulates formation of tissue
factor and release of PF-3 from platelets
3. Two initial pathways that share a common pathway at the
end; differ in starting point and stimulus
4. Requires:
a. clotting factors (procoagulants)
1) protein enzymes
2) synthesis of 4 factors requires vitamin K
b. fibrinogen
c. Ca2+ ions
E. Lathrop-Davis / E. Gorski / S. Kabr hel 13 Circulatory System: Blood
5. Measuring coagulation (clotting)
a. coagulation time
b. bleeding time
6. Pathways of coagulation – both result in activation of
factor X Fig. 18.13, p. 668
a. extrinsic pathway
1) starts with tissue factor (factor III)
2) fewer steps in pathway
b. intrinsic pathway
1) starts with activation of proenzymes in blood
2) includes many steps
3) may occur in unbroken blood vessel if cholesterol
plaque is present
c. common pathway of coagulation
1) activated factor X activates prothrombin activator
2) prothrombin activator activates prothrombin
(becomes thrombin)
3) thrombin
i. acts on fibrinogen (soluble) to turn it into fibrin
(insoluble)
ii. also activates factor XIII, which creates cross-
links between fibrin fibers to stabilize clot
7. Clot retraction and fibrinolysis
a. retraction
1) accomplished by platelets that adhere to fibrin
fibers
2) pulls torn edges of vessel together
3) reduces size of damaged area
b. fibrinolysis
1) breakdown of fibrin fibers by plasmin
i. formed from plasminogen
ii. plasminogen activated by:
(a) thrombin
(b) tissue plasminogen activator (t-PA)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 14 Circulatory System: Blood
8. Natural control of clotting
a. plasma anticoagulants (e.g., antithrombin III)
b. heparin (released by basophils and mast cells;
accelerates activity of antithrombin III)
c. thrombomodulin (released by endothelial cells; converts
thrombin into different enzyme that activates protein
C, which inactivates a number of clotting factor
enzymes and stimulates production of plasmin)
d. prostacyclin (inhibits platelet aggregation; opposes
action of thrombin, ADP and several other factors)
9. Clinical control of clotting
a. Heparin – synthetic version of naturally occurring
compound; interferes with conversion of prothrombin
to thrombin; enhances action of antithrombin III
b. Warfarin (Coumadin) – interferes with production of
clotting factors that require vit. K for synthesis
c. Aspirin – interferes with platelet aggregation
D. Bleeding Disorders
1. Hemophilia – recessive, X-linked genetic disease in which clotting factors (most
often factor VIII, but several others as well) are not made in adequate amounts
2. von Willebrand disease – most common genetic bleeding disorder; failure to
make adequate amounts of von Willebrand’s factor, which stabilizes factor VIII
3. Thrombus – clot formed in intact vessel wall; often occurs where cholesterol
plaques are present; may break free or completely block vessel
4. Embolus – abnormal mass (especially a clot) in blood
a. clot may start out as thrombus or may form spontaneously in pooled blood
b. may result in embolism (blockage of vessel) and cause infarct (tissue
damage)
1) stroke
2) myocardial infarct
E. Lathrop-Davis / E. Gorski / S. Kabr hel 15 Circulatory System: Blood
E. Lathrop-Davis / E. Gorski / S. Kabr hel 16 Circulatory System: Blood
TOPIC 2
Circulatory System – Heart
Ch. 19, pp. 681-715
Objectives
Introduction
1. Describe the function, size and location of the heart.
2. Describe the structure and function of the pericardium.
3. Distinguish between the fibrous and serous pericardium.
Structure of the Heart
1. Describe the internal and external anatomy of the heart.
2. Explain the importance of the endothelial lining of the heart in terms of platelet
function.
3. Describe the structure of the heart wall.
4. Describe the chambers of the heart.
5. Describe the structure and function of the heart valves.
6. Identify and state the functions of the major blood vessels associated with the heart.
7. Diagram the flow of blood through the and great vessels from the right ventricle to
the right atrium assuming correct, unidirectional flow of blood and including coronary
blood flow as well as pulmonary and systemic circuits.
8. Explain the importance of anastomoses to maintaining adequate coronary circulation.
Action Potential in Cardiac Muscle
1. Describe the microscopic structure of cardiac muscle and list several ways in which it
differs from skeletal muscle.
2. Describe the events of an action potential in cardiac muscle and compare them to
skeletal muscle.
3. Differentiate between the roles of calcium ions in autorhythmic and contractile
cardiac muscle cells.
4. Explain the source(s) and role of calcium ions in cardiac muscle contraction.
5. Trace the normal initiation and conduction of impulses through the myocardium.
6. Explain the importance of the following:
a. delay of action potential at the AV node
b. conduction of action potential to papillary muscle before rest of ventricular
myocardium
c. plateau in the action potential of contractile cells
E. Lathrop-Davis / E. Gorski / S. Kabr hel 17 Circulatory System: Heart
Electrocardiogram
1. Differentiate between the electrocardiograph and electrocardiogram.
2. Describe a normal ECG
3. Relate the conduction of the action potential through the heart to the
electrocardiogram (ECG/EKG).
4. Analyze electrocardiograms to determine whether they represent normal heart
rhythms, or the arrhythmias tachycardia, bradycardia, or ventricular fibrillation.
Cardiac Cycle
1. Define systole, diastole and cardiac cycle.
2. Describe the events of one complete cardiac cycle.
3. Relate pressure changes in the heart to the flow of blood through the heart.
4. Trace the pathway of blood flow through the heart during one complete cardiac cycle
including the position and function of the valves.
5. Compare and contrast the atrioventricular and semilunar valves in terms of their roles
in the movement of blood through the heart and the timing of their opening and closing.
6. Relate heart sounds their functions and indicate their clinical significance.
7. Discuss the function of the papillary muscles and chordae tendinae during the cardiac
cycle.
8. Relate the events of the cardiac cycle to the waves seen in an ECG.
Cardiac Output
1. Define cardiac output.
2. Define end-diastolic volume (EDV= preload), end-systolic volume (ESV), afterload and
stoke volume (SV).
3. Discuss the relationships among EDV, ESV, SV, CO and HR.
4. Describe the factors that affect SV and relate them to cardiac output (CO).
5. Define the Frank-Starling law of the heart and explain its physiological significance.
6. Contrast the effects of sympathetic and parasympathetic control of heart rate and
strength of contraction.
7. Discuss the factors that affect heart rate (HR) and relate them to CO.
8. Explain how EDV, ESV, SV, and HR affect one another to maintain a near constant CO
at rest.
9. Explain how EDV, ESV, SV, and HR may change to increase CO during exercise and
stress.
10. Explain the neural control of heart rate including the role of pressoreceptors
(baroreceptors) and chemoreceptors.
11. Relate the actions of digitalis, calcium-channel blockers, and beta-adrenergic
antagonists (beta blockers) to cardiac function and explain why they alter CO.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 18 Circulatory System: Heart
Disorders
1. Describe the following disorders of the heart:
a. Pericarditis
b. Cardiac tamponade
c. Rheumatic heart disease
d. Murmur
i. Valvular incompetance
ii. Stenosis
e. Myocardial infarction
f. Arrhthmias
i. Tachycardia
ii. Bradycardia
iii. Flutter
iv. Fibrillation
v. First-, second-, and third-degree atrioventricular (AV) block
vi. Bundle branch block
g. Ectopic foci
h. Preventricular contractions (PVCs)
i. Congestive heart failure (also discuss the causes and mechanism)
2. Explain how ventricular fibrillation lead to ischemia in the myocardium and how that
contributes to decreased myocardial function.
3. Relate the results of AV block to the ECG.
See also A.D.A.M. Interactive Physiology – Cardiovascular System
* Anatomy Review: The Heart
* Intrinsic Conduction System
* Cardiac Action Potential
* Cardiac Cycle
* Cardiac Output
E. Lathrop-Davis / E. Gorski / S. Kabr hel 19 Circulatory System: Heart
E. Lathrop-Davis / E. Gorski / S. Kabr hel 20 Circulatory System: Heart
Topic 2: Circulatory System – Heart
I. Overview
A. Function, Size & Location
1. Function: provide pressure for movement of blood through
blood vessels by alternately contracting (systole) and
relaxing (diastole)
2. Size
a. 250 – 350 grams (about the size of a fist)
b. Extends from 2nd rib to 5th intercostal space
3. Location Fig. 19.1, p. 682
a. Within the pericardial cavity in mediastinum of the
thoracic cavity
b. Directly posterior to the sternum, ~2/3 lies left of
midline
B. Pericardial Cavity & Coverings of the Heart
1. Fibrous pericardium
a. Outer layer of pericardial sac
b. Stabilizes heart in mediastinum
2. Serous pericardium
a. Parietal layer
b. Visceral layer = epicardium
3. Pericardial cavity
a. Pericardial fluid
b. Pericarditis – inflammation of the pericardium
1) normally, hinders production of serous fluid
2) cardiac tamponade – severe case of pericarditis in
which fluid in pericardial cavity increases
II. Structure of the Heart
A. Chambers and External Structures of the Heart Fig. 19.4, p. 685
1. 2 Atria
a. Auricles
b. Coronary sulcus = atrioventricular groove
2. 2 Ventricles
a. Anterior interventricular groove
b. Posterior interventricular groove
E. Lathrop-Davis / E. Gorski / S. Kabr hel 21 Circulatory System: Heart
3. Base
4. Apex
B. Structure of the Heart Wall Fig. 19.2, p. 683
1. Epicardium = visceral pericardium
a. Serous membrane
1) mesothelium (simple squamous epithelium)
2) areolar connective tissue
b. Adipose accumulates in grooves
2. Myocardium – cardiac muscle, blood vessels and nerves
a. Muscle arranged in spiral or circular bundles
b. Fibrous skeleton supports and anchors cardiac muscle
3. Endocardium – endothelium (simple squamous epithelium) &
associated connective tissue)
C. Great Vessels of Heart Fig. 19.4, p. 685 & 686
1. Arteries
a. Pulmonary artery (trunk)
b. Aorta
2. Veins
a. Pulmonary veins
b. Superior & inferior venae cavae
c. Coronary sinus
d. Other coronary veins
D. Internal Anatomy
1. Atria & atrioventricular (AV) valves Fig. 19.8, p. 691
a. Interatrial septum
1) fossa ovalis
b. Pectinate muscles
c. Atrioventricular (AV) valves – allow blood to flow from
atria to ventricles when latter are relaxing; prevent
flow from ventricles to atria when ventricles are
contracting
1) mitral = bicuspid
2) tricuspid
E. Lathrop-Davis / E. Gorski / S. Kabr hel 22 Circulatory System: Heart
d. Valve disorders
1) rheumatic heart disease (RHD)
2) murmur
i. incompetence
ii. stenosis
2. Ventricles & Semilunar Valves Fig. 19.8, p. 691; Fig. 19.4, p. 687
a. Papillary muscles
b. Chordae tendineae
c. Trabeculae carnae
d. Semilunar (SL) valves
3. Heart Sounds Fig. 19.20, p. 704
a. 1st heart sound – “lub”
b. 2nd heart sound – “dup”
c. Murmur
4. Fibrous Skeleton
a. Internal connective tissue framework
b. Functions include:
1) stabilizes positions of muscle cells and valves
2) supports muscle cells, blood vessels, nerves
3) helps spread force of contraction through heart
4) prevents over-distention
5) helps maintain shape of heart
6) separates atrial and ventricular musculatures
E. Microanatomy of the Myocardium
1. Structure
a. Cardiac muscle Fig. 19.11, p. 694
1) branching, uninucleate, short
2) striated – sliding filament movement
E. Lathrop-Davis / E. Gorski / S. Kabr hel 23 Circulatory System: Heart
b. Connected by intercalated discs
1) gap junctions
i. functional syncytium
2) desmosomes
c. Numerous large mitochondria
1) aerobic respiration using glucose, fatty acids, amino
acids, lactic acid
2) high O2 demand
3) myoglobin
III. Blood Flow Through the Heart Fig. 19.5, p. 688
A. Two circuits:
1. Pulmonary
a. to and from capillary beds associated with alveoli of
lungs where gas exchange between blood and air takes
place
b. brings deoxygenated blood to lungs; returns
oxygenated blood to heart
2. Systemic
a. to and from capillary beds of the rest of the body
where gas exchange between blood and tissues takes
place
b. brings oxygenated blood to tissues; returns
deoxygenated blood to heart
B. Coronary Blood Supply Fig. 19.7, p. 690
1. General
a. anastomoses
b. blood flow enters coronary vessels during diastole,
empties during systole
c. autoregulation
d. capillaries present in endomysium (endo = within;
mysium = muscle)
1) found in areolar CT within intracellular space
between muscle cells
2) endomysium connected to fibrous skeleton
E. Lathrop-Davis / E. Gorski / S. Kabr hel 24 Circulatory System: Heart
2. Arteries
a. branches of aorta
b. supply oxygen-rich blood to myocardium
c. right coronary artery - serves right atrium and right
ventricle, SA and AV nodes, and posterior walls of both
ventricles
d. left coronary artery
1) serves interventricular septum and anterior walls of
both ventricles, left atrium and posterior wall of
left ventricle
2) branches into anterior interventricular artery and
circumflex artery
3. Veins Fig. 19.4, pp. 685-686; Fig. 19.7, p. 690
a. coronary sinus
1) great cardiac vein
2) other coronary veins flow into coronary sinus
b. anterior cardiac veins
4. Disorders
a. occlusion
b. ischemia
c. infarction
1) disruption of arterial circulation serving the area
2) disruption of venous drainage (less common)
IV. Action Potential and Conduction
A. Functional Comparison with Skeletal Muscle
1. All-or-none law
a. in skeletal muscle, applies to motor units
b. in cardiac muscle, applies to entire organ
2. Means of stimulation
a. skeletal muscle
b. cardiac muscle
1) autorhythmicity = certain cells are self-excitatory
(depolarize spontaneously)
2) autonomic nervous system innervation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 25 Circulatory System: Heart
i. parasympathetic innervation
ii. sympathetic innervation
3. Length of absolute refractory period
a. in skeletal muscle – 1-2 ms allows tetanus
b. in cardiac muscle ~ 250 ms prevents tetanus
B. Types of cardiac muscle cells
1. Autorhythmic cardiac muscle cells
a. autorhythmic
b. produce pacemaker potentials
c. conduct action potentials (impulses) through
myocardium
d. not contractile
2. Contractile cardiac muscle cells
a. action potential leads to contraction
b. responsible for alternating contraction (systole) and
relaxation (diastole) that creates pressure on blood
C. Action Potential: Autorhythmic Cells Fig. 19.11, p. 694
2+ + +
1. Contain two types of Ca channels, K channels, Na (really
Na+/K+) channels
2. Sequence of events
a. gradual change in membrane potential from resting (-
60 to -70 mV) net gain of + charge as cells slowly
depolarization = pacemaker potential; results when:
1) voltage-gated K+ channels close
2) Na+ channels open (allow more Na+ to enter than K+
to leave)
b. at threshold (~ -40 mV), voltage-gated Ca2+ channels
open Ca2+ enters cell depolarizes
c. depolarization causes 2nd type of Ca2+ channels to
open rapid depolarization phase of action potential
1) depolarization causes voltage-gated K+ channels to
open cell repolarizes as K+ leaves
2) decrease in voltage causes Ca2+ channels to close,
aids repolarization K+ channels start to close;
cycle starts over
E. Lathrop-Davis / E. Gorski / S. Kabr hel 26 Circulatory System: Heart
D. Conduction Through the Heart
1. Action potential spreads rapidly through conduction system
and contractile cells due to gap junctions present
2. Atria and ventricles functionally separated by fibrous
skeleton
3. Time to total depolarization ~ 220 ms (~ 0.22 s) in a
healthy heart
E. Conduction Pathway Fig. 19.14, p. 698; Fig. 19.17, p. 700
1. Sinoatrial (SA) Node
a. located in right atrial wall, inferior to opening of
superior vena cava
b. sinus rhythm
c. rate
1) intrinsic rate ~ 100 APs/min
2) ~ 75 APs / min at rest under hormonal and neural
control
d. AP spreads to atria and to AV node via internodal
pathway
2. Atrioventricular (AV) Node
a. located in inferior interatrial septum above tricuspid
valve
b. connects atria and ventricles
c. short delay (~ 0.1 s)
3. Atrioventricular (AV) Bundle (bundle of His)
4. Right and Left Bundle Branches – run through
interventricular septum toward apex of heart
5. Purkinje fibers
a. run through interventricular septum to apex of heart
where they turn and run superiorly through outer wall
of ventricles
b. supply papillary muscles before rest of ventricular wall
F. Action Potential: Contractile Cells Fig. 19.12, p. 695
2+ + +
1. Ca channels; K channels; Na channels
2. Depolarization passes from conducting cells
a. contractile cell depolarizes from resting (ventricles ~ -
90mV; atria ~ -80 mV) to threshold fast voltage-
gated sodium channels open Na+ rushes in
E. Lathrop-Davis / E. Gorski / S. Kabr hel 27 Circulatory System: Heart
depolarization to ~ +30 mV (positive feedback); Na+
channels close membrane potential begins to fall
b. depolarization triggers:
1) inactivation (closure) of voltage-gated K+ channels
2) opening of voltage-gated Ca2+ channels Ca2+
enters sarcoplasm from extracellular fluid and
sarcoplasmic reticulum
c. combination of Ca 2+ influx and inactivation of K+
channels results in plateau, coupled with slow return of
Na+ channels to ready position results in long absolute
refractory period
d. rapid repolarization occurs as Ca2+ channels close and
K+ channels open returns membrane to resting
V. Electrocardiogram (ECG)Measuring electrical changes in heart Fig. 19.16, p. 700
1. Electrocardiograph – instrument
a. 12 standard leads (I, II and III are most commonly
used)
2. Electrocardiogram – recording
a. series of deflections from baseline – correspond to
spread of action potential through myocardium
B. Electrocardiogram Analysis
1. ECG shows:
a. overall heart rate
b. wave shape, height and duration
c. deviation from baseline (normal)
2. Waves and segments
a. P wave
1) P-R (P-Q) interval
b. QRS complex
1) Q-T segment
c. T wave
3. Common cardiac arrhythmias
a. sinus bradycardia
b. sinus tachycardia
c. atrial flutter
E. Lathrop-Davis / E. Gorski / S. Kabr hel 28 Circulatory System: Heart
d. atrial fibrillation
e. ventricular fibrillation
f. atrioventricular block – impaired conduction from SA
node through AV node
1) 1st degree block
2) 2nd degree block
3) 3rd degree block = complete block
g. bundle branch block
1) right bundle branch block (RBBB)
2) left bundle branch block (LBBB)
VI. Cardiac Cycle and Relationship to ECG Fig. 19.19, p. 703
A. Alternating systole (contraction) and diastole (relaxation)
leads to 3 different periods:
B. Ventricular filling
1. blood passively flows into ventricles from atria through
open AV valves (~ 70%); heart is at rest
2. Atrial depolarization (P wave) atrial systole – moves
remaining blood (~30%) into ventricles
C. Ventricular depolarization (QRS complex) ventricular
systole
1. Period of isovolumetric contraction – ventricles contract,
push blood against AV valves AV valves close; pressure
rises without change in volume
2. Period of ejection – increased pressure in ventricles pushes
semilunar valves open and blood forced into elastic arteries
(pulmonary artery, aorta)
D. Period of isovolumetric relaxation
1. Ventricular repolarization (T wave) ventricles relax
2. Semilunar valves close when pressure in ventricles <
pressure in aorta
a. dicrotic notch – increase in aortic pressure as blood
pushes back against closed semilunar valves
3. Ventricles relax with both sets of valves closed; pressure
drops but volume stays the same
E. Lathrop-Davis / E. Gorski / S. Kabr hel 29 Circulatory System: Heart
4. Period of isovolumetric relaxation continues until pressure
in ventricles < pressure in atria at which time blood
pressure opens AV valves and filling begins again
VII. Cardiac Output (CO)
A. Volume of blood ejected from each ventricle per minute
at rest, normally 5 L / min
B. CO = SV x HR
C. Stroke volume (SV): SV = EDV – ESV; average~70 ml.
1. Controlling factors
a. EDV = end diastolic volume (preload)
1) amount of blood in the ventricle at the end of filling
2) normally, 120-130 ml
3) main controller of stroke volume
4) Frank-Starling law of the heart
i. greater venous return greater stretch
stronger contraction
ii. decreased return less stretch weaker
contraction
b. ESV = end systolic volume
1) amount of blood in the ventricle at the end of
contraction
2) normally, ~ 50 ml
3) affected by afterload (pressure against which
heart must pump blood into arteries – normally
estimated based on arterial pressure)
c. ventricular contractility (strength of contraction)
1) positive inotropic agents
i. sympathetic innervation
ii. hormones
(a) epinephrine
(b) glucagon, thyroxine
iii. Digitalis (cardiac glycoside; Digoxin)
2) negative inotropic agents
i. rising extracellular K+
ii. calcium channel blockers (e.g., Verapamil)
iii. acidosis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 30 Circulatory System: Heart
2. Factors that increase SV
a. increased ventricular contractility (see positive
inotropic agents)
b. increased EDV
1) increased time for filling
2) increased venous return
i. increased skeletal muscle activity
ii. inspiration
iii. venoconstriction
3) increased blood volume
c. decreased afterload - decreased mean arterial
pressure (MAP)
3. Factors that decrease SV
a. decreased ventricular contractility (see negative
inotropic agents)
b. decreased EDV
1) decreased time for filling (increased heart rate or
changes in rhythm)
2) decreased venous return
i. decreased blood volume
ii. decreased skeletal muscle activity
iii. expiration
iv. decreased venous pressure
c. increased afterload - increased mean arterial pressure
D. Heart Rate
1. number of beats per minute
2. intrinsic rhythm altered by:
a. autonomic innervation
b. hormones
3. Factors that increase heart rate
a. increased temperature (increases metabolic rate)
b. sympathetic division of the ANS – innervates SA node,
AV node, ventricular myocardium
1) increases action potential frequency of SA node
2) increases action potential conduction at AV node
E. Lathrop-Davis / E. Gorski / S. Kabr hel 31 Circulatory System: Heart
3) increases strength of contraction (see ventricular
contractility above)
4) preganglionic fibers arise from lower cervical and
upper thoracic spinal cord segments
c. hormones
1) epinephrine
2) thyroxine
d. altered ion concentrations (See Albasan et al. for
additional information if you are interested)
1) decreased Ca 2+ (hypocalcemia) - increases irritability
spastic contractions
2) increased K+ (hyperkalemia) – lowers resting
potential, causes tachycardia and decreases
strength of contraction
4. Factors that decrease heart rate
a. parasympathetic division of the ANS – innervates SA
node, AV node
1) decreases action potential frequency and increases
delay in conduction pathway decreases heart rate
2) preganglionic fibers are from vagus nerve
b. decreased temperature
c. altered ion concentrations (See Albasan et al. for
additional information if you are interested)
1) reduced Ca 2+ (hypocalcemia) – decreases ability to
contract and ability of autorhythmic cells to
depolarize
2) decreased K+ (hypokalemia) – hyperpolarizes
membrane leading to feeble heart beats
3) increased sodium (hypernatremia) prevents calcium
from entering cardiac cells cardiac arrest
5. Neural control of heart rate Fig. 19.25, p. 707
a. response to pressure of blood on vessel (or atrium) wall
b. cardiac centers in medulla oblongata (reticular
formation)
1) baroreceptors (pressoreceptors) found in aorta,
carotid arteries, right atrium
2) cardioacceleratory center
E. Lathrop-Davis / E. Gorski / S. Kabr hel 32 Circulatory System: Heart
3) cardioinhibitory center
c. increased blood pressure
1) stimulates baroreceptors in aortic sinus and carotid
sinus impulses sent through vagus (from aorta)
and glossopharyngeal nerve (from carotids)
stimulates cardioinhibitory center (CIC)
i. CIC inhibits cardioacceleratory center (CAC)
ii. CIC sends parasympathetic impulses through
vagus
d. decreased blood pressure
1) results in less stimulation of baroreceptors
fewer impulses through vagus and glossopharyngeal
nerves CIC not stimulated CAC becomes more
active
2) CAC sends impulses through sympathetic nerves to
SA node, AV node, ventricular myocardium heart
rate and strength of contraction increase
increased CO increased BP
e. right atrial (Bainbridge) reflex
1) occurs when right atrial pressure increases
stimulates CAC increased sympathetic impulses
to heart increased heart rate and strength of
contraction moves blood more quickly through
atrium decreased right atrial pressure
6. Clinical control of heart rate
a. digitalis
b. calcium-channel blockers
c. beta blockers
VIII.Congestive Heart Failure
A. Results from failure to balance venous return and stroke
volume
B. Pumping action of heart insufficient to meet needs of body
C. Causes:
1. Intrinsic causes (weaken contractions)
a. myocardial infarction, cardiomyopathy
E. Lathrop-Davis / E. Gorski / S. Kabr hel 33 Circulatory System: Heart
2. Extrinsic causes – make it more difficult to eject blood
into aorta
a. systemic hypertension
b. coronary atherosclerosis
c. aortic stenosis
D. Mechanism of Congestive Heart Failure
Increased systemic resistance
Increased force of left ventricular contraction
Increased left ventricular oxygen demand
Increased left ventricular hypoxia
Decreased left ventricular contraction decreased arterial pressure
Increased left ventricular end diastolic pressure
Increased left atrial pressure
Pulmonary edema decreased pulmonary return
Increased pulmonary vascular resistance right ventricular failure
Decreased oxygen supply to myocardium
E. Lathrop-Davis / E. Gorski / S. Kabr hel 34 Circulatory System: Heart
TOPIC 3
Circulatory System – Blood Vessels
Ch. 20, pp. 718-742
Objectives
Introduction
1. Describe the general pattern of circulation.
Structure and Functions of the Blood Vessels
1. Describe the layers of the blood vessel wall.
2. Compare and contrast the structure and function of the various types of arteries,
capillaries, and veins.
4. Describe the structural changes that are seen in the blood vessels as one follows the
path from elastic arteries through muscular arteries, arterioles, capillaries, venules
and veins.
5. Relate the structural changes described above to the differences in function seen
among the different types of blood vessels.
6. Compare and contrast the 3 types of capillaries in terms of structure and function.
7. Give examples of where one would find each of the 3 types of capillaries.
Circulatory Patterns
1. Describe the general systemic and pulmonary circulation patterns and the hepatic
portal, hypophyseal portal, coronary, fetal and cerebral circulation patterns.
2. Trace the following circulatory pathways:
a. general body circulation
b. coronary circulation
c. pulmonary circulation
d. fetal circulation
3. Describe the circulation to the brain including the circle of Willis and dural sinuses.
4. State the functions of the hepatic and hypophyseal portal systems and discuss how
they differ from most circulation patterns.
Disorders
Describe the following disorders of circulation and explain their effects on blood flow in
the area served:
1. Varicose veins
2. Phlebitis
3. Atherosclerosis
4. Occlusive coronary atherosclerosis
5. Arteriosclerosis
6. Aneurysm
E. Lathrop-Davis / E. Gorski / S. Kabr hel 35 Circulatory System: Blood Vessels
See A.D.A.M. Interactive Physiology – Cardiovascular System
* Anatomy Review: Blood Vessel Structure and Function
E. Lathrop-Davis / E. Gorski / S. Kabr hel 36 Circulatory System: Blood Vessels
Topic 3: Circulatory System – Blood Vessels
I. Functions and Types of Blood Vessels
A. Function
1. Act as conduits for blood
2. Separate systemic and pulmonary systems more
efficient delivery of oxygen and nutrients, removal of
wastes
B. Types of vessels
1. Arteries – carry blood away from the heart
2. Veins – return blood to heart
3. Capillaries – sites of exchange of materials between blood
and tissues
II. Blood Vessel Histology Fig. 20.1, p. 719
A. Three layers of blood vessel wall
1. Tunica interna (tunica intima)
a. endothelium (simple squamous epithelium)
b. subendothelial layer
2. Tunica media
a. varying amounts of dense connective tissue
b. smooth muscle
1) vasomotor tone
i. vasoconstriction
ii. vasodilation
3. Tunica externa
a. connective tissue
b. nerve fibers, lymphatic vessels
c. vasa varsorum – blood vessel system in tunica externa
of larger blood vessels
III. Types of Blood Vessels Fig. 20.2, p. 720
A. Elastic (Conducting) Arteries
1. Aorta and its major branches
2. Functions:
a. carry blood rapidly away from heart toward capillary
beds
E. Lathrop-Davis / E. Gorski / S. Kabr hel 37 Circulatory System: Blood Vessels
b. help decrease fluctuations in blood pressure by
expanding during ventricular systole (decreases
pressure) and recoiling during ventricular diastole
(maintains pressure on blood to keep it moving)
3. Structure
a. large diameter, large lumen
b. thick walls
c. lots of elastic fibers (elastin)
B. Muscular (Distributing) Arteries
1. Account for most of the named arteries
2. Function: deliver blood to organs
3. Structure:
a. internal diameter smaller than elastic arteries
b. thick tunica media with lots of smooth muscle
C. Arterioles
1. Function: distribute blood to tissues within organs major
controller of blood flow into capillaries
2. Structure:
a. branch and become smaller
b. walls thickness decreases, endothelium and scattered
smooth muscle cells near capillaries
D. Capillaries
1. Function: sites of exchange between blood and tissues
2. Structure:
a. most consist of tunica interna only
b. some with scattered pericytes (smooth muscle cells)
3. Three structural types: Fig. 20.3, p. 724
a. continuous
1) endothelial cells continuous
2) endothelial cells held together by tight junctions
i. intercellular clefts – gaps in tight junctions
ii. tight junctions continuous in brain (blood-brain
barrier)
b. fenestrated capillaries
1) some endothelial cells with pores, most covered with
membrane
E. Lathrop-Davis / E. Gorski / S. Kabr hel 38 Circulatory System: Blood Vessels
2) very permeable
3) small intestine, some endocrine glands, kidney
(glomeruli)
c. sinusoids
1) large irregular lumens slows blood flow
2) walls fenestrated or incompletely lined with
endothelial cells
i. in liver endothelium is discontinuous where
macrophages (Kupffer cells) form part of vessel
wall
ii. in spleen, phagocytes on outside of endothelial
lining extend processes into lumen of sinusoid
3) few tight junctions allow large molecules (e.g.,
proteins) to pass through
4) located in liver, bone marrow, lymphoid tissue, some
endocrine glands
4. Capillary beds Fig. 20.4, p. 725
a. many capillary branches from arteriole =
microcirculation
b. metarteriole-thoroughfare channel
1) fast, direct connection between arteriole and venule
2) terminal arteriole metarteriole thoroughfare
channel venule
c. true capillaries
1) branches of metarteriole
i. rejoin to thoroughfare channel
ii. precapillary sphincter
(a) ring of smooth muscle
(b) controls movement into capillary bed
2) amount of blood entering depends on gross needs of
body (vasomotor nervous control) and local needs of
tissue (local chemical cues)
E. Post-capillary venules
1. Function: collect blood from capillary beds
2. Leaky endothelium with few pericytes
3. Many white blood cells (WBCs)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 39 Circulatory System: Blood Vessels
F. Veins
1. Functions
a. return blood to heart
b. act as blood reservoirs = capacitance vessels
1) ~ 65% of body’s blood is in veins
2. Gradually increase in size and thickness
3. All 3 tunics present, but thinner than arteries of
corresponding size
a. little smooth muscle or elastin
b. relatively thicker tunica externa
4. Under low pressure
a. valves prevent backflow
b. varicose veins
5. Phlebitis
G. Venous sinuses
1. Function: collect blood under low pressure
2. Structure:
a. flattened veins with wall of endothelium only
b. supported by surrounding tissues
3. Coronary sinus, dural sinuses
IV. Vascular Anastomoses
A. Arterial anastomoses collateral channels
1. Brain (Circle of Willis)
2. Joints
3. Abdominal organs
4. Heart
B. Arteriovenous anastomoses - metarteriole thoroughfare
channel
C. Venous anastomoses
V. Circulatory Patterns Fig. 20.2, p. 720
A. General Pattern: Ventricles of heart elastic arteries
muscular arteries arterioles capillaries venules
veins atria of heart
B. Two main systems:
1. Pulmonary circulation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 40 Circulatory System: Blood Vessels
a. right ventricle pulmonary trunk lungs pulmonary
veins left atrium
b. takes deoxygenated blood to lungs for exchange of
gases
2. Systemic circulation
a. left ventricle aorta body tissues superior and
inferior venae cavae right atrium
b. takes oxygenated blood to tissues, removes wastes
C. Special circulatory patterns – See lab
1. Hepatic portal circulation (covered with digestive system) Fig. 20.27, p. 771
2. Hypophyseal portal circulation Fig. 17.5, p. 617
3. Coronary circulation Fig. 19.7, p. 690
4. Cerebral circulation Fig. 20.20, p. 755; Fig. 20.25, p. 767
5. Fetal circulation Fig. 29.13, p. 1136
a. by-pass developing lungs
1) ductus arteriosus
2) foramen ovale
b. gas exchange at placenta
1) umbilical arteries
2) umbilical vein
VI. Vascular Disorders
A. Varicosities
B. Phlebitis
C. Atherosclerosis
D. Occlusive coronary atherosclerosis
E. Arteriosclerosis
F. Aneurysm
E. Lathrop-Davis / E. Gorski / S. Kabr hel 41 Circulatory System: Blood Vessels
E. Lathrop-Davis / E. Gorski / S. Kabr hel 42 Circulatory System: Blood Vessels
TOPIC 4
Circulatory System – Blood Flow,
Blood Pressure, and Capillary Dynamics
Ch. 20, pp. 727-747
Objectives
Blood Flow Through Vessels
1. Define blood flow.
2. Discuss the role of valves in maintaining unidirectional flow.
3. Define resistance.
4. List and describe the factors that create resistance to flow through vessels.
5. Describe how blood flow velocity changes through the vascular system.
Blood Pressure
1. Define blood pressure.
2. Define and describe systolic, diastolic, pulse, and mean arterial, capillary and venous
blood pressures.
3. Discuss the clinical importance of systolic, diastolic, and pulse pressures.
4. Describe the ascultatory method of determining blood pressure.
5. Calculate pulse and mean arterial pressures given diastolic and systolic pressure.
6. Define pulse and identify points at which pulse may be felt.
7. Describe how blood pressure changes through the vascular system.
8. Describe the factors that affect venous return.
Controlling Blood Pressure
1. Discuss the effects of cardiac output (CO), peripheral resistance, and blood volume on
pressure.
2. Discuss the role of the elastic arteries in blood pressure during ventricular systole and
diastole.
3. Diagram the factors that contribute to blood pressure.
4. Discuss the role of baroreceptors (pressoreceptors) in the carotid artery, aortic arch,
and right atrium in regulating blood pressure.
5. Discuss the role of chemoreceptors for O 2 , CO2 , pH on systemic and local peripheral
resistance.
6. Discuss the role of the medulla oblongata in regulating blood pressure.
7. Define vasomotor tone and describe how it is controlled.
8. Discuss the role of higher brain centers in controlling blood pressure.
9. Discuss the short-term chemical controls of blood pressure.
10. Discuss the long-term control of blood pressure.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 43 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
11. Diagram the control of blood pressure including the roles of the autonomic nervous
system and endocrine system and the individual factors that they control.
12. Discuss how and why blood pressure varies between genders, and with changes in
posture, weight, stress, mood and activity level.
Blood Distribution and Reservoirs
1. Describe and explain the changes in blood distribution that occurs during exercise
compared to rest.
2. Describe the blood reservoirs and explain their significance.
3. Define and state the functions of tissue perfusion.
4. Diagram the short- and long-term regulation of blood flow to tissues.
Capillary Dynamics
1. Describe the factors that influence movement of fluid between blood and IF.
2. Define and describe diffusion, osmosis and bulk flow.
3. Relate diffusion, osmosis and bulk flow to movement of fluid and solutes across the
capillary wall.
4. Define hydrostatic pressure and osmotic pressure.
5. Relate hydrostatic pressure and osmotic pressure to movement of fluid and solutes
across the capillary wall.
6. Define net hydrostatic pressure and discuss the factors that support and oppose it.
Disorders
1. Define hypotension and describe the various types.
2. Compare and contrast the causes and effects of orthostatic and acute hypotension.
3. Compare the causes and treatment of primary and secondary hypertension.
4. Discuss the causes and types of circulatory shock.
5. Define edema and explain how the following contribute to edema:
a. increased MAP
b. venous obstruction
c. leakage of plasma proteins into interstitial space
d. hypothyroidism (see A&P I Unit 11 – Endocrine System)
e. decreased plasma protein production
f. damage to lymphatic drainage system
See also A.D.A.M. Interactive Physiology – Cardiovascular System
* Measuring Blood Pressure
* Factors That Affect Blood Pressure
* Blood Pressure Regulation
* Autoregulation and Capillary Dynamics
E. Lathrop-Davis / E. Gorski / S. Kabr hel 44 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
Topic 4: Circulatory System –
Blood Flow, Blood Pressure and Capillary Dynamics
I. Blood Flow
A. General
1. “volume of blood flowing through a vessel, an organ, or the
entire circulation in a given period”
2. Measured in ml/min
3. To entire system: blood flow = cardiac output (CO);
relatively constant at rest
4. To specific organ or tissue: flow varies with demand
BF = P / R
a. directly proportional to blood pressure gradient (P)
between two points
b. inversely proportional to peripheral resistance (R)
B. Resistance to Blood Flow
1. “measure of the amount of friction blood encounters as it
passes through vessels”
2. Peripheral resistance (R) – resistance in peripheral vessels
accounts for most resistance in system
3. Sources of resistance:
a. blood viscosity
1) directly proportional
2) affected by number of blood cells (e.g.,
polycythemia)
b. blood volume
1) dehydration
2) water retention
c. total blood vessel length
1) angiogenesis
d. blood vessel diameter
1) inversely proportional to resistance
i. increased diameter decreased resistance
E. Lathrop-Davis / E. Gorski / S. Kabr hel 45 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
ii. varies as inverse of radius to 4th power (1/r4 )
iii. e.g., double radius resistance decreases to
1/16 of original resistance
2) controlled mainly at small arterioles in response to
neural and chemical controls
3) sudden decrease in size of lumen turbulance
increased resistance
II. Blood Pressure
A. General
1. “force per unit area exerted on the wall of a blood vessel
by its contained blood”
2. In common usage, “blood pressure” usually refers to blood
pressure in systemic arteries near heart
3. Pressure gradient keeps blood flowing
4. Measured in mm Hg (millimeters of mercury)
5. Varies through vascular system Fig. 20.5, p. 729
a. highest and most variable in aorta and other elastic
arteries
b. decreases through arterioles and capillaries
c. lowest in venae cavae
B. Arterial Blood Pressure
1. Varies with:
a. age
b. gender
c. weight
d. stress level
e. mood
f. posture
g. physical activity
2. Depends on:
a. compliance (distensibility) of elastic arteries
b. stroke volume
E. Lathrop-Davis / E. Gorski / S. Kabr hel 46 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
3. Rises during ventricular systole, decreases during diastole
a. systolic pressure (PS) ~ 110-120 mm Hg
1) ejection period of cardiac cycle (semilunar valves
open and blood is pumped out)
2) compliance decreases pressure needed to eject
blood into arteries
3) increased stroke volume increased pressure
b. diastolic pressure (PD ) ~ 70-80 mm Hg
1) semilunar valves closed
2) elastic recoil of arteries contributes to continued
pressure movement of blood
C. Pulse Pressure & Mean Arterial Pressure
1. Pulse Pressure (PP)
a. difference between systolic (P S) and diastolic (PD )
pressures: PP = PS – PD
b. increased with increased stroke volume (SV) during
exertion
c. increased by arteriosclerosis
2. Mean Arterial Pressure (MAP)
a. average pressure in main arteries
b. heart spends more time in diastole
c. MAP = diastolic pressure (P D) + (pulse pressure [PP]
divided by 3)
d. MAP = PD + (PP /3)
3. Measuring Pulse and Blood Pressure
a. pulse Fig. 20.11, p. 737
1) palpation of pulse points (pressure points)
2) pulse can be felt at major arteries
3) stronger closer to heart
4) count number of beats in a given time period
b. blood pressure – auscultatory method
1) sphygmomanometer
2) brachial artery
3) Korotkoff sounds
E. Lathrop-Davis / E. Gorski / S. Kabr hel 47 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
D. Capillary and venous blood pressures
1. Capillary pressure
a. pressure drops from ~ 40 mm Hg (at arterial end) to ~
20 mm Hg (at venous end)
b. lower pressure helps prevent breakage of capillary walls
& decreases fluid loss to tissues
2. Venous pressure
a. low, steady pressure
b. venous return aided by:
1) valves
2) respiratory pump
3) muscular pump
i. “milking” promotes return
ii. prolonged inactivity or prolonged contraction
pooled blood
III. Maintaining Blood Pressure
A. Blood pressure (BP) varies directly with: Fig. 20.7, 20.8
1. Cardiac output (CO; see Topic 3)
a. controlled by cardiac centers in medulla oblongata
b. cardioacceleratory center (CAC) sympathetic
outflow
c. cardioinhibitory center (CIC) parasympathetic
outflow
2. Peripheral resistance (PR)
3. Blood volume (BV)
B. Short-term control of resistance Fig. 20.8, p. 733
1. Mechanisms include neural and chemical controls
2. Goals:
a. alter distribution to meet demands of various
organs/tissues
b. maintain overall MAP through vasomotor tone
3. Neural control
a. vasomotor center controls vasomotor tone
1) located in medulla oblongata (cardiovascular center)
2) maintains vasomotor tone in all vessels
3) vasomotor fibers, most of which use norepinephrine
(NE)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 48 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
i. increased sympathetic activity
vasoconstriction increased BP
4) some fibers to vessels of skeletal muscle use ACh
i. increased sympathetic activity vasodilation
increased flow to skeletal muscle (little
importance to overall BP)
b. Factors affecting vasomotor tone
1) reflexes initiated by baroreceptors or
chemoreceptors
2) baroreceptor-initiated reflexes
i. baroreceptors (pressoreceptors) present in
carotid sinus*, aortic arch*, most other elastic
arteries of neck and thorax
ii. increased BP stimulates baroreceptors
(a) sensory impulses inhibit CAC
(b) concurrent sensory impulses stimulate CIC
iii. prolonged hypertension causes baroreceptors to
“reset” to higher pressure
3) chemoreceptor-initiated reflexes
i. chemoreceptors in aortic arch and large arteries
of neck
ii. connected to CAC and vasomotor center
iii. respond to oxygen (O2 ), pH (hydrogen ion),
carbon dioxide (CO2 ) levels
iv. decreased O2 or pH, or increased CO2
impulses to:
(a) CAC
(b) vasomotor center
4) influence of higher brain centers on vasomotor tone
i. cerebral cortex and hypothalamus connected to
cardiac centers (CAC and CIC) and vasomotor
center in medulla oblongata
E. Lathrop-Davis / E. Gorski / S. Kabr hel 49 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
ii. threats initiate “fight-or-flight” response
mediated by hypothalamus activates CAC and
VMC
iii. hypothalamus directs changes in flow during
activity and to control body temperature
4. Short-term chemical controls – chemicals that act on
vessels, heart or blood volume
a. norepinephrine (NE; from adrenal medulla)
vasoconstriction
b. epinephrine (epi; from adrenal medulla):
1) vasoconstriction, except in skeletal and cardiac
muscle
2) increased heart rate and strength of contraction
3) nicotine (in tobacco) – stimulates sympathetic
ganglionic neurons and adrenal medulla
c. antidiuretic hormone (ADH; a.k.a., vasopressin; from
neurohypophysis)
1) stimulates water reabsorption
2) at high levels, causes vasoconstriction
d. angiotensin II (see long-term control below and Topic
10 Urinary System)
1) produced from angiotensinogen in response to renin
from kidney
2) causes intense vasoconstriction
3) stimulates secretion of ADH and aldosterone (long
term control)
e. atrial natriuretic peptide (ANP; atria of heart) –
antagonizes aldosterone and causes general vasodilation
f. alcohol
1) inhibits ADH secretion
2) depresses vasomotor center
g. endothelium-derived factors
1) inflammatory chemicals (see Topic 6 Resistance)
i. histamine, prostacyclins, kinins and others
ii. released during inflammatory response
iii. vasodilation and increased capillary permeability
E. Lathrop-Davis / E. Gorski / S. Kabr hel 50 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
2) nitric oxide (NO) – major vasodilator released in
response to high blood flow; causes systemic and
local vasodilation
C. Long-Term Control: Renal Regulation
1. Regulates blood volume (BV) Fig. 20.9, p. 735
2. Blood volume important to: venous pressure, venous return,
EDV, SV, CO
3. Control:
a. direct renal control – responds to both increased and
decreased blood pressure (important with large
changes; See Topic 10 Urinary System)
1) increased BP increased filtration increased
water loss decreased BV
2) decreased BP decreased filtration decreased
water loss increased BV
b. indirect renal control – responds to decreased blood
pressure
1) renin-angiotensin pathway (See Topic 10 Urinary
System)
i. decreased BP juxtaglomerular cells of kidney
tubules secrete renin enzymatic cascade
converts angiotensinogen to angiotensin I
angiotensin II
ii. kidney also releases renin in response to
sympathetic impulses
2) angiotensin II
i. stimulates aldosterone secretion
ii. stimulates ADH secretion
iii. causes vasoconstriction
D. Blood Pressure Disorders
1. Hypotension – systemic BP < 100 mm Hg
a. orthostatic hypotension
b. chronic hypotension
1) possible causes: poor nutrition, Addison’s disease,
hypothyroidism (See A&P I Unit XI – Endocrine
System)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 51 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
c. acute hypotension
1) most often due to hemorrhage
2) sign of circulatory shock
2. Hypertension
a. long-term elevation of arterial pressure > 140/90
b. results in damage to heart, kidneys, brain (stroke),
blood vessels overall
c. primary hypertension
1) possible causes:
i. diet high in Na+ , saturated fat, cholesterol; low
in K+ , Ca2+ , Mg2+
ii. obesity, heredity, age
iii. stress, smoking
2) treatment:
i. changes in diet, weight loss, exercise, stress
management
ii. antihypertensive drugs: diuretics, beta-blockers,
calcium-channel blockers
d. secondary hypertension (~ 10% of cases)
1) causes:
i. excess renin secretion
ii. arteriosclerosis
iii. hyperthyroidism
iv. Cushing’s disease
2) treatment aimed at cause
IV. Blood Distribution
A. Changes in blood distribution during exercise Fig. 20.12, p. 738
1. Total pumped increases from ~ 5,800 ml/min at rest to ~
17,500 ml/min during exercise
2. Brain – flow remains relatively steady (~750 ml/min)
3. Skeletal muscle, heart – flow increases dramatically to
supply oxygen and nutrients and remove wastes
4. Skin – flow increases for heat loss (thermoregulation)
5. Kidney – flow decreases (decreases urine output)
6. Abdominal organs – flow decreases (redirected elsewhere)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 52 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
7. Other – flow decreases (redirected to skeletal muscle &
heart)
B. Tissue Perfusion
1. Blood flow through tissues
2. Varies with need Fig. 20.12, p. 738
3. Functions:
a. delivery of oxygen & nutrients, removal of wastes
b. gas exchange in lung
c. absorption of nutrients from gut
d. urine production in kidney
C. Velocity of blood flow Fig. 20.13, p. 739
1. Inversely related to total cross-sectional area of blood
vessels to be filled
2. Branching of arteries increases cross-sectional area
3. Lowest in capillaries - allows time for exchange between
blood and tissue
4. Increases as capillaries join to form venules and venules
join to form veins
D. Autoregulation of blood flow
1. Local (intrinsic) regulation of blood flow
a. response of blood vessels serving tissues to needs of
tissue
b. inadequate blood flow decreased tissue metabolism
cell death
2. Long-term autoregulation increase in number and size of
blood vessels = angiogenesis
3. Short-term autoregulation
a. metabolic control of blood flow
1) maintains proper chemical environment for cells
2) causes vasodilation of precapillary sphincter to
increase blood flow
3) important chemicals include:
i. nitric oxide (NO)
(a) attaches to hemoglobin in lungs as O 2 is
loaded
(b) released at capillaries as O2 is released
ii. inflammatory chemicals (histamine, kinins)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 53 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
iii. active hyperemia
(a) decreased oxygen and/or other nutrients
(b) increased K+ , H + (decreased pH), adenosine,
lactic acid
b. myogenic control of blood flow
1) maintains relatively steady flow to tissues in spite
of changes in overall BP
2) response of vascular smooth muscle to stretech
i. increased stretch vasoconstriction
decreased flow
ii. decreased stretch vasodilation increased
flow
3) reactive hyperemia
i. dramatic increase in blood flow following removal
of blockage
ii. results from:
(a) stretching of arteriole upstream from
blockage, and
(b) accumulation of wastes in tissue
V. Capillary Dynamics
A. Movement across capillary is based on gradients
1. Solute gradient (diffusion)
2. Water gradient (osmosis)
3. Pressure gradient (hydrostatic pressure)
B. Diffusion
1. Small water-soluble molecules pass between endothelial
cells through small clefts (desmosomes are loose cell
junctions)
2. Lipids and lipid-soluble (non-polar) materials pass directly
through the lipid bilayer of the endothelial cells
3. Osmosis
a. special form of diffusion in which solvent (water) moves
across membrane (diffusion of water)
b. water moves toward area of higher solute
concentration
E. Lathrop-Davis / E. Gorski / S. Kabr hel 54 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
C. Bulk fluid flow
1. Moves fluids and dissolved substances through capillary
walls together using the following forces
a. hydrostatic pressure: the physical pressure exerted by
a fluid in an enclosed space; fluids and dissolved
substances move from areas of high to areas of low
hydrostatic pressure
b. osmotic pressure: “pull” exerted on solvent by solute in
solution (solution with more solute has greater osmotic
pressure)
2. Forces moving fluid OUT of capillary Fig. 20.15, p. 743
a. moves fluid INTO interstitial space
b. HPc = capillary hydrostatic pressure
1) also called capillary blood pressure (or blood
hydrostatic pressure)
2) pushes fluid out of capillary
3) 35 mm Hg at the arterial end of the capillary
(average)
4) 17 mm Hg at the venous end of the capillary
(average)
c. OPif = interstitial fluid osmotic pressure
1) proteins in the interstitial fluid exert osmotic
pressure on the plasma
2) pulls fluid out of capillary into tissues
3) average value is 1mm Hg
d. total out of capillary at arterial end ~ 36 mm Hg
e. total out of capillary at venous end ~ 18 mm Hg
3. Forces moving fluid INTO capillary
a. moves fluid OUT of interstitial space
b. HPif: interstitial fluid hydrostatic pressure
1) pressure pushing interstitial fluid into the capillary
2) ranges from slightly negative to slightly positive
(effect of lymphatic system)
3) 0 mm Hg generally used in equations
c. OPc = capillary osmotic pressure
1) presence of large, nondiffusible molecules (e.g.,
plasma protein)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 55 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
2) draws fluid into the capillary from the interstitial
fluid
3) average value is 26 mm Hg
d. Total into capillary at arterial end: ~ 26 mm Hg
e. Little change along capillary from arterial to venous end
D. Net Filtration Pressure
1. Sum of all hydrostatic and osmotic forces acting on fluids as they move through
capillary walls
2. Can be seen as difference between forces moving out of capillary versus forces
moving fluid into it
a. NFP = [sum of outward forces] – [sum of inward forces]
= [HPc + OPif] - [OPc + HPif]
b. at arterial end: HPc = 35mm Hg; OPif = 1 mm Hg; OPc = 26 mm Hg; HPif = 0 mm
Hg
= [35mm Hg + 1 mm Hg] – [26 mm Hg + 0 mm Hg]
= 10 mm Hg (flow OUT of capillary at arterial end)
c. at venous end: HPc = 17 mm Hg; OPif = 1 mm Hg; OPC = 26 mm Hg; HPif = 0 mm
Hg
= [17 mm Hg + 1 mm Hg] – [26 mm Hg + 0 mm Hg]
= - 8 mm Hg (net flow INTO capillary at venous end)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 56 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
d. results is net LOSS of fluid from capillary to interstitial fluid
1) 10 mm Hg loss at arterial end; 8 mm Hg gain at venous end
2) net loss of 2 mm Hg overall
3. Can also be seen as difference in hydrostatic pressures + difference in osmotic
pressures
a. = (HPc – HPif) - (OPc – OPif)
b. difference in hydrostatic pressures: Net Hydrostatic Pressure = HPc – HPif
1) at arterial end: 35mm Hg – 0 mm Hg = 35mm Hg
2) at venous end: 17mm Hg – 0mm Hg = 17mm Hg
c. difference in osmotic pressures: Net Osmotic Pressure = OPc – OPif
1) 26 mm Hg – 1 mm Hg = 25 mm Hg
2) normally does not change along length of capillary
d. at the arterial end
NFP = [35mm Hg – 0mm Hg] – [26mm Hg – 1mm Hg]
= 35mm Hg – 25mm Hg
= +10 mm Hg (fluid moves OUT OF the capillary)
e. at the venous end
NFP = [17mm Hg – 0mm Hg] – [26mm Hg – 1mm Hg]
= 17 mm Hg – 25mm Hg
= -8 mm Hg (fluid moves INTO the capillary)
VI. Disorders
A. Edema
1. Abnormal accumulation of fluid in tissues
2. Predict the effect of the following on capillary dynamics:
increased MAP
venous obstruction
allergic reaction
hypothyroidism
decreased plasma protein
filiariasis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 57 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
B. Circulatory shock
1. “any condition in which blood vessels are inadequately filled and blood cannot
circulate normally”
2. Results in decreased flow to tissues leading to cell death (necrosis)
3. Signs:
a. rapid, but weak, heart beat (“thready” pulse)
b. intense vasoconstriction
c. sharp drop in blood pressure
4. Treatment: rapid replacement of fluids
5. Types of circulatory shock
a. cardiogenic shock – often due to myocardial damage (multiple infarcts)
b. hypovolemic shock
1) most common type
2) causes: acute hemorrhage, severe vomiting or diarrhea, extensive burns
c. vascular shock (vasodilation)
1) anaphylaxis (anaphylactic shock)
2) neurogenic shock
3) septicemia
4) prolonged exposure to heat (e.g., sunbathing)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 58 Circulatory System: Blood Flow,
Blood Pressure & Capillary Dynamics
TOPIC 5
Lymphatic System
Ch. 21, pp. 778-787
Objectives
Introduction
1. List the components and functions of the lymphatic system.
2. Compare and contrast lymph and blood.
Structure and Functions of the Lymphatic Vessels
1. Describe the structure of lymphatic vessels.
2. Contrast and contrast of the various types of lymphatic vessels.
3. Compare and contrast of veins and lymphatic vessels.
4. Compare and contrast lymphatic capillaries and blood capillaries.
Lymph Flow Through Vessels
1. Describe the production and general circulation of lymph.
2. List and describe the forces responsible for the circulation of lymph.
Lymphoid Tissues and Organs
1. Describe the structure and functions of mucosa-associated lymphatic tissue (MALT),
tonsils, spleen, and thymus gland.
2. Describe the structure and function of the lymph nodes.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 59 Lymphatic System
E. Lathrop-Davis / E. Gorski / S. Kabr hel 60
Topic 5: Lymphatic System
I. Functions of the Lymphatic System
A. Return fluid back to blood
B. Return proteins back to blood
C. Transport fats and fat soluble vitamins (D,A,K,E) from GI
tract to blood
D. Protect and defend body against disease (house agranular
leukocytes)
II. Lymph
A. Filtered interstitial fluid
B. Enters lymphatic capillaries under low pressure
C. Similar to blood but with:
1. No erythrocytes
2. More leukocytes
3. Less protein
4. More fat
III. Lymphatic Vessels Fig. 21.1, p. 779
A. Lymphatic capillaries
1. Cells overlap to form valves within lumen
2. Cells connected by fibers to structures within tissue
3. Collect excess tissue fluid
4. Lacteals
B. Lymphatic vessels (lymphatics)
1. Similar to veins, but with thinner walls, less muscle, less
connective tissue, more valves
2. Carry lymph to lymphatic trunks
C. Lymphatic trunks Fig. 21.2, p. 780
1. Formed by union of lymphatic vessels
2. Carry lymph to lymphatic ducts
D. Lymphatic ducts Fig. 21.2, p. 780
1. Formed by union of lymphatic trunks
2. Empty into subclavian veins on right and left
3. Right lymphatic duct
a. formed from jugular, subclavian, and
bronchomediastinal trunks on right
E. Lathrop-Davis / E. Gorski / S. Kabr hel 61 Lymphatic System
b. drains upper right quadrant of body
4. Thoracic duct
a. cysterna chyli
1) intestinal trunk
2) right and left lumbar trunks
b. left jugular, subclavian, and bronchomediastinal trunks
c. drains upper left quadrant, abdominopelvic regions, and
legs
E. Lymph Circulation
1. Moves along pressure gradient
2. Presence of valves keeps flow moving in one direction
3. Mechanisms believed to contribute to pressure:
a. “milking” by skeletal muscle
b. pressure changes during breathing
c. pulsating of neighboring elastic arteries
d. contraction of smooth muscle in walls of larger
lymphatic vessels and ducts
IV. Lymphoid Tissues
A. Lymphatic nodules (follicles)
1. Germinal center
2. Common in mucosae of respiratory, urinary and digestive
systems
B. Tonsils Fig. 23.3, p. 838
1. Lingual and palatine tonsils
2. Adenoid (pharyngeal tonsil)
C. Mucosa-associated lymphatic tissue = MALT
1. Aggregates of lymphatic nodules (follicles) found in
mucosae of respiratory and digestive systems
2. Peyer’s patches
V. Lymphoid Organs Fig. 21.5, p. 783
A. Larger, more organized, encapsulated structures consisting
largely of lymphocytes
B. Lymph nodes Fig. 21.4, p. 782
1. Function: filter debris, pathogens and other antigens from
circulating lymph
E. Lathrop-Davis / E. Gorski / S. Kabr hel 62 Lymphatic System
2. Structure:
a. small, ovoid, covered with connective tissue capsule
b. hilus
c. outer cortex
1) trabeculae
2) stroma
3) follicles with germinal centers
d. inner medulla
3. Circulation through a node:
a. afferent lymphatics
b. subcapsular sinus
c. lymph sinuses
d. efferent lymphatics
C. Spleen Fig. 21.6, p. 784
1. Functions
a. RBC production in fetus
b. stores platelets and iron
c. macrophages
d. helps initiate immune response to circulating antigens
2. Location: left upper quadrant of abdominal cavity, lateral
to stomach
3. Structure
a. hilus
b. red pulp
c. white pulp
D. Thymus Fig. 21.7, p. 785
1. Functions
a. secretes hormones (thymosin and thymopoietin) that
stimulate T cell lymphocytes to become
immunocompetent (enables them to respond
appropriately to pathogens)
b. most active in childhood (atrophies after adolescence)
2. Location: in lower neck region
E. Lathrop-Davis / E. Gorski / S. Kabr hel 63 Lymphatic System
3. Structure:
a. 2 lobes divided into lobules by extensions (septae) of
the fibrous tissue capsule
b. each lobule consists of
1) outer cortex of closely packed cells including
dividing lymphocytes
2) reticuloendothelial cells
i. blood-thymus barrier
ii. thymic hormones
3) inner medulla
i. contains mature T cell lymphocytes
ii. T cells able to leave and enter blood or lymph
iii. reticuloendothelial cells form Hassall’s (thymic)
corpuscles (function unknown)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 64 Lymphatic System
TOPIC 6
Immune System – Resistance to Disease
Ch. 21, pp. 778-787
Objectives
Introduction
1. Define immunity.
2. Describe the functions of the immune system.
3. Describe and differentiate between nonspecific and specific resistance.
4. Define pathogen.
5. Differentiate between microbes and macroscopic parasites.
Nonspecific Resistance
1. Describe the physical barriers that provide resistance.
2. List the various leukocytes and describe the roles in nonspecific cellular responses to
disease.
3. Describe the general mechanism of phagocytosis.
4. Describe the role of the various leukocytes in phagocytosis and actions of phagocytes
in resistance.
5. Describe natural killer (NK) cells and explain their role in resistance.
6. Distinguish among microphages, macrophages, T cells, B cells, NK cells and eosinophils
in terms of structure and function.
7. Describe the functions, signs, causes and process of inflammation.
8. Diagram the steps of inflammation.
9. Diagram the steps of phagocytosis.
10. Define fever and describe its role in resistance.
11. List and describe the functions of the antimicrobial proteins.
12. Compare the functions of the various proteins involved in specific and nonspecific
resistance.
13. Describe the two pathways of complement activation.
Specific Resistance
1. Describe the main characteristics of specific resistance.
2. Define: antigen, complete antigen, hapten, antigenic determinant, epitope, self-antigen,
major histocompatibility protein, agglutination, agglutinogen, agglutinen, precipitation,
neutralization
3. Differentiate between cellular and humeral immunity.
4. List and describe the lymphocytes involved in specific resistance.
5. Define immunocompetent and explain how and where B cells and T cells become
immunocompetent.
6. Describe and explain the role of antigen-processing cells (APCs) in immunity.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 65 Immune Syst em: Resistance to Disease
7. Describe the role of the thymus gland in antibody production.
Humoral Immunity
1. Describe how B cells become activated.
2. Differentiate between the primary response and secondary response to an antigen.
3. Compare and contrast naturally acquired active immunity, naturally acquired passive
immunity, artificially acquired active immunity, and artificially acquired active
immunity, and give an example of each.
4. Describe the general structure of immunoglobulins and explain the roles of the variable
and constant regions.
5. List the five classes of immunoglobulins and describe their functions.
6. Describe the mechanisms of antibody action.
Cell-Mediated Immunity
1. Define cell-mediated immunity.
2. List and describe the major types of T cells involved in cell-mediated immunity.
3. Describe and differentiate among the roles and actions of cytotoxic T cells, helper T
cells, suppressor and delayed-hypersensitivity T cells.
4. Describe the steps of T cell activation.
Organ Transplants
1. Describe and differentiate among the types of organ transplants; give examples of
each.
2. Identify treatments to suppress the immune system used to prevent transplant
rejection.
Disorders
1. Differentiate between genetic and acquired immunodeficiencies.
2. Describe the following immunodeficiencies:
a. Severe combined immunodeficiency syndrome (SCID)
b. Acquired immunodeficiencies
i. Acquired immune deficiency syndrome (AIDS)
ii. Hodgkin’s disease
3. Discuss the causes and symptoms of the following autoimmune disorders:
a. Multiple sclerosis (MS)
b. Myasthenia gravis
c. Grave’s disease
d. Type I diabetes mellitus (IDDM)
e. Systemic lupus erythematosis (SLE)
f. Rheumatoid arthritis (RA)
4. Differentiate between acute and delayed hypersensitivity disorders.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 66 Immune Syst em: Resistance to Disease
5. Discuss the causes and symptoms of the following hypersensitivity disorders:
a. Acute hypersensitivities
b. Anaphylaxis
c. Delayed hypersensitivity
6. Differentiate between local and systemic anaphylaxis.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 67 Immune Syst em: Resistance to Disease
E. Lathrop-Davis / E. Gorski / S. Kabr hel 68 Immune Syst em: Resistance to Disease
Topic 6: Immune System – Resistance to Disease
I. Overview
A. Functional rather than anatomical system
1. Protects against pathogens
a. microbes
b. parasites
2. Eliminates tissues and cells that have been damaged,
infected or killed
3. Distinguishes between self and non-self
B. Two types of resistance work together against disease
1. Innate = nonspecific
a. general defense against wide range of pathogens
b. rapid response
c. in place at birth
d. mechanisms: intact membranes, phagocytes,
antimicrobial chemicals, inflammation
2. Adaptive = specific
a. specific response to pathogens
b. slower than innate system
c. acquired as person is exposed
d. mechanisms: T cell lymphocytes, antibodies
II. Nonspecific (Innate) Resistance Table 22.2, p. 801
A. Physical Barriers
1. Intact Skin Fig. 5.3, p. 152
a. consists of keratinized stratified squamous epithelium
b. relatively dry (inhibits growth of some pathogens)
c. sebaceous gland secretions include antibacterial
chemicals (lysozyme, certain fatty acids)
d. normal bacterial flora compete with pathogens
e. slightly acidic
f. slightly salty (sweat)
2. Intact mucous membranes
a. line body cavities open to outside (digestive, urinary,
reproductive, respiratory tracts)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 69 Immune Syst em: Resistance to Disease
b. intact barrier – nonkeratinized stratified squamous
epithelium lines openings (mouth, pharynx, esophagus,
vagina, parts of rectum and urethra)
c. slightly acidic (mouth, vagina, urethra) to highly acidic
(stomach)
d. antimicrobial proteins (lysozyme in saliva and lacrimal
fluid)
e. normal bacterial flora compete with pathogens
3. Mucus
a. hairs help trap particles
b. cilia move particles
ciliary escalator
B. Cellular Responses
1. Inflammation
a. functions:
1) prevents spread of pathogens or damaging chemicals
to other tissues
2) removes dead cells and pathogens
3) prepares tissue for repair
b. signs of inflammation
1) redness
2) heat
3) swelling
4) pain
c. inflammatory chemicals
1) histamine
i. secreted by basophils and mast cells
ii. vasodilation and increased capillary permeability
iii. antihistamines
2) kinins (proteins; e.g., bradykinin)
i. vasodilation, increased permeability
ii. induce chemotaxis
iii. stimulate pain receptors
3) prostaglandins (derived from fatty acids)
i. sensitize blood vessels to other inflammatory
chemicals
E. Lathrop-Davis / E. Gorski / S. Kabr hel 70 Immune Syst em: Resistance to Disease
ii. stimulate pain receptors
4) complement (see below)
5) cytokines
i. number of proteins released by various cells
ii. many enhance various aspects of inflammation
d. process of inflammation Fig. 22.2, p. 797
1) release of inflammatory chemicals
2) vascular changes: vasodilation and increased
capillary permeability, resulting in:
i. hyperemia and exudate formation
ii. increased temperature
iii. increased oxygen and nutrients to tissue and
cellular defenders
iv. leakage of clotting proteins
3) phagocyte mobilization Fig. 22.3, p. 798
i. chemotaxis and leukocytosis
(a) increased number of leukocytes
(b) chemotaxis
(c) margination (“pavementing”)
(d) diapedesis
(e) phagocytosis of pathogens and debris
pus formation
ii. neutrophils respond most quickly
iii. monocytes respond more slowly
(a) enter tissue and become macrophages with
more lysosomes
(b) associated with chronic infection
2. Phagocytes
a. macrophages
1) reside in tissues
2) derived from monocytes
3) free (wandering) macrophages
E. Lathrop-Davis / E. Gorski / S. Kabr hel 71 Immune Syst em: Resistance to Disease
4) fixed macrophages
Kuppfer cells (liver), microglia (brain)
b. neutrophils = microphages
1) respond quickly to localized infections
2) degranulation
c. eosinophils - respond most to parasitic worms
d. mast cells
1) reside in tissues
2) release histamine during inflammation
3) less common
4) respond to variety of bacteria
e. mechanism of phagocytosis Fig. 22.1, p. 795
1) microbial adherence
i. recognition of bacteria as non-self
ii. more difficult with encapsulated bacteria
iii. opsonization
2) formation of pseudopodia and engulfment of
particle
3) union of phagocytic vesicle with lysosome
4) digestion of particle
5) exocytosis of indigestible material
6) respiratory burst
i. used against pathogens that resist lysosomal
enzymes (e.g., tuberculosis bacteria)
ii. stimulated by chemicals released by adaptive
immune system
iii. produces free radicals (e.g., NO)
7) defensins
3. Natural Killer (NK) Cells
a. large, granular lymphocytes
b. immunological surveillance
c. kill cancer cells and virally infected cells
d. release perforins
1) produce channels in target cell membrane
2) cause nucleus to degrade
e. produce other chemicals that enhance inflammation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 72 Immune Syst em: Resistance to Disease
4. Antimicrobial Proteins
a. complement
1) group of 20+ plasma proteins (circulate in inactive
form)
2) two pathways of activation: Fig. 22.5, p. 800
i. classical pathway
(a) linked to immune system
(b) activation results from interaction of
antigen-antibody complex with key
complement proteins
ii. alternative pathway – interactions of other
complement proteins with polysaccharides on
surface of certain microorganisms
3) both pathways start cascade resulting in
i. enhances actions of nonspecific and specific
resistance mechanisms, including inflammation
and opsonization
ii. causes lysis of bacterial cells
b. interferons (IFNs)
1) group related proteins secreted by body cells
infected with virus
2) stimulate synthesis of PKR in nearby uninfected
cells
i. blocks protein synthesis at ribosomes
3) also stimulate macrophages and NK cells
4) produced artificially and used clinically to treat
genital herpes (caused by herpes virus), also used in
treatment of hepatitis C, and viral infections in
organ transplant patients
c. lysozyme
C. Fever
1. Increased body temperature in response to pathogens
2. Involves resetting of “thermostat” in hypothalamus
a. response to pyrogens secreted by leukocytes and
macrophages in response to bacteria and other foreign
particles
E. Lathrop-Davis / E. Gorski / S. Kabr hel 73 Immune Syst em: Resistance to Disease
3. Mild fever
a. enhances activity of phagocytes and tissue repair
b. causes liver and spleen to sequester iron and zinc
4. High fever (> 104 oF or 40 oC)
III. Specific (Adaptive) Resistance = Acquired Resistance
A. Characteristics
1. Antigen specific
2. Systemic
3. Differentiates between normal (self) and foreign (non-self)
antigens
4. Memory
B. Types
1. Humoral = antibody-mediated immunity
result of specific antibodies (proteins) present in blood
2. Cellular = cell-mediated immunity
result of specific group of cells = T cell lymphocytes
C. Antigens (Ags)
1. Substances that activate immune system and elicit
response
a. immunogenicity
b. reactivity
2. Antigenic determinants = epitope Fig. 22.6, p. 803
3. Complete antigen has both characteristics
a. large molecules typically with more than one antigenic
determinant
b. most foreign proteins, nucleic acids, some lipids, some
large polysaccharides
4. Haptens = incomplete antigens – reactive but not
immunogenic
a. generally small molecules
b. hapten can combine with other molecules to become
complete antigen (e.g., penicillin)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 74 Immune Syst em: Resistance to Disease
5. Self-antigens – major histocompatibility complex (MHC)
proteins
a. glycoproteins found on individual’s own cells
b. two types:
1) class I MHC proteins – found on all cells of body
2) class II MHC proteins – found only on cells involved
in immune response
6. Terms
a. agglutination – antibody binds to antigenic determinants
of cells and cross-links several together resulting in
clumping
b. precipitation – antibody binds to antigenic determinants
of soluble antigen (e.g., toxin) and causes clumping
c. neutralization – antibody covers active site(s) on
antigen
D. Cells of the Immune System
1. Lymphocytes
a. become immunocompetent in primary lymphoid organs
(bone marrow or thymus) where they learn self-
tolerance
b. move to secondary lymphoid tissue to become exposed
to antigens then return to blood and lymph circulation
c. types: Fig. 22.8, p. 805
1) B cells = B lymphocytes
i. become immunocompetent in bone marrow
ii. develop into plasma cells after exposure to
antigen and produce specific antibodies
2) T cells = T lymphocytes
i. become immunocompetent in thymus
ii. active in cellular immunity
2. Antigen-presenting cells (APCs)
a. types:
1) dendritic cells
2) Langerhan’s cells
3) macrophages
4) activated B cell lymphocytes
E. Lathrop-Davis / E. Gorski / S. Kabr hel 75 Immune Syst em: Resistance to Disease
b. engulf foreign particles and present fragments on own
surface to T cells
E. Humoral Immunity Fig. 22.9, p. 807
1. Relies on B cells
2. Activated (stimulated to complete differentiation) by
exposure to antigens
a. primary response – 1st exposure
1) antigen binds to specific receptor on specific B cell
2) B cell engulfs antigen (receptor-mediated
endocytosis)
3) daughter cells differentiate into plasma cells that
secrete antibodies and memory B cells
(immunological memory)
b. secondary response – subsequent exposures
1) memory B cells give rise to plasma cells that
produce antibodies
2) much faster than primary response
3. Passive versus active humoral immunity
Active Passive
Naturally Infection Antibodies passed from
Acquired mother to fetus or infant
Artificially Vaccine (dead or Injection of gamma
Acquired attenuated pathogens) globulin
4. Antibody structure and types
a. immunoglobulins (Igs) or gamma globulins
b. general structure: Fig. 22.12, p. 810
1) consist of 4 polypeptide chains: 2 light chains, 2
heavy chains held together by disulfide bonds =
antibody monomer
2) variable region
i. give specificity to antibody
ii. includes antigen-binding sites
E. Lathrop-Davis / E. Gorski / S. Kabr hel 76 Immune Syst em: Resistance to Disease
3) constant region
i. includes stem region of heavy chains and
proximal parts of both heavy and light chains
ii. stem region determines actions and classes of
antibodies
c. antibody classes Table 22.3, p. 811
1) differ in basic structure
2) IgG
i. most abundant and diverse plasma antibody in
both primary and secondary responses
ii. protects against circulating bacteria, viruses,
toxins
iii. activates complement
iv. crosses placenta to protect fetus
3) IgM
i. acts as antigen receptor on B cell membrane
ii. 1st antibody released during primary response
iii. causes agglutination and activates complement
4) IgA
i. found primarily in mucus and other secretions
(e.g, saliva, sweat, intestinal juice, milk)
ii. prevents attachment of antigens to epithelium
5) IgD - acts as antigen receptor
6) IgE
i. present in skin, gastrointestinal and respiratory
tract mucosae, tonsils
ii. binds to mast cells and basophils
iii. normally in low amounts in plasma; increases
during allergy and chronic parasitic infection of
GI tract
5. Mechanisms of Antibody Action Fig. 22.13, p. 812
a. enhance phagocytosis
1) neutralization
2) agglutination
3) precipitation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 77 Immune Syst em: Resistance to Disease
b. activation of complement
1) enhances phagocytosis
2) enhances inflammation
3) causes cell lysis
F. Cell-Mediated Immunity
1. Involves T cells
2. Types of T cells Table 22.4, p. 818
a. cytotoxic T cells (TC) Fig. 22.17, p. 820
1) destroy body cells that are infected by antigen
(viruses, bacteria, internal parasites) or have non-
self antigens (e.g., cancer cells)
2) mechanism seems to involve release of perforin onto
membrane of affected cell
3) other mechanisms
i. lymphotoxin – causes fragmentation of target
cell DNA
ii. tumor necrosis factor (TNF) triggers cell death
(= apoptosis)
iii. gamma interferon – stimulates macrophages
b. helper T cells (TH) - stimulates production of B cells
and cytotoxic T cells Fig. 22.16, p. 817
c. suppressor T cells (TS) – limits activity of T and B cells
after infection has been beaten
d. delayed hypersensitivity T cells (TDH) –
1) involved in delayed allergic reactions by secreting
interferon and other cytokines
2) enhance nonspecific phagocytosis by macrophages
3. T Cell Activation
a. Step 1 – Antigen binding
1) T cell antigen receptor (TCR) binds to antigen-MHC
protein complex on cell
b. Step 2 – Costimulation – recognition of costimulatory
signals stimulates clonal division of T cells into various
types
E. Lathrop-Davis / E. Gorski / S. Kabr hel 78 Immune Syst em: Resistance to Disease
4. Cytokines
a. released by macrophages and T cells
b. some act as costimulators
IV. Organ Transplants
A. Types:
1. Autograft – from one site to another in same person
2. Isograft – between identical twins or members of same
clone
3. Allograft – between nonidentical individuals of same
species
4. Xenograft – between different species
B. Rejection
1. Occurs when antigens on donor tissue are attacked by
recipient’s immune system
2. Immunosuppressive therapy
a. corticosteroids
b. cytotoxic drugs
c. radiation (X ray) therapy
d. antilymphocyte globulins
e. immunosuppressant drugs (e.g., cyclosporine)
V. Disorders
A. Immunodeficiencies
1. Severe combined immunodeficiency syndromes (SCID) –
genetic deficiencies of immune system
2. Acquired immunodeficiencies
a. may result from anticancer drugs
b. Hodgkin’s disease
c. acquired immune deficiency syndrome (AIDS)
1) caused by HIV virus transmitted in secretions
(especially blood, semen, vaginal secretions)
2) changes ratio of helper to suppressor T cells
(decreases number of TH)
3) allows opportunistic infections to proliferate
E. Lathrop-Davis / E. Gorski / S. Kabr hel 79 Immune Syst em: Resistance to Disease
B. Autoimmune diseases
1. Multiple sclerosis (MS) (See A&P I Unit IV Nervous Tissue)
2. Myasthenia gravis (See A&P I Unit V Electrophysiology)
3. Type I diabetes mellitus (IDDM) (See A&P I Unit XI Endocrine System)
4. Grave’s disease (See A&P I Unit XI Endocrine System)
5. Systemic lupus erythematosis (SLE)
6. Rheumatoid arthritis (RA)
C. Hypersensitivities = allergies Fig. 22.19, p. 826
1. Immediate hypersensitivities = acute hypersensitivities = type I
hypersensitivities
a. occurs in person after initial exposure (response to 1 st exposure normally not
seen)
b. begin within seconds of subsequent contact with antigen
c. anaphylaxis – most common; local or systemic; mediated by interleukin 4 (IL-
4), which stimulates B cells to mature into IgE-secreting plasma cells, which
stimulate release of histamine from basophils and mast cells
1) local – e.g., hives in skin; hay fever; asthma; GI reactions
2) systemic
i. caused by introduction of allergen into blood (e.g., venom in bee sting;
penicillin injection)
ii. causes widespread release of histamine widespread vasodilation
widespread loss of fluid to tissues radical drop in BP
anaphylactic shock (See Topic 4 Blood Pressure – Shock)
iii. also causes bronchoconstriction
iv. treated with epinephrine
2. Delayed hypersensitivity (type IV) reactions
a. cell-mediated response
b. involves cytotoxic and delayed hypersensitivity T cells
c. most familiar are contact dermatitis, responses to some heavy metals,
cosmetics and deodorants
E. Lathrop-Davis / E. Gorski / S. Kabr hel 80 Immune Syst em: Resistance to Disease
TOPIC 7
Respiratory System
Ch. 23, pp. 835-879
Objectives
Introduction
1. List the components and functions of the respiratory system.
Upper Respiratory Structures and Respiratory Tree
1. List and distinguish between the conducting and respiratory passageways.
2. Describe the structure and functions of the nose, nasal cavity and paranasal sinuses.
3. Describe the structure and respiratory functions of the regions of the pharynx.
4. Describe the structure and respiratory functions of the larynx.
5. Describe the role of the larynx in sound production.
6. Describe the structure and respiratory functions of the trachea.
7. Describe the structure and respiratory functions of the bronchial tree.
8. Trace the pathway of air flow entering through the nares to the alveoli.
9. Describe the structural and histological changes that occur from the mouth/nose to
the alveoli.
10. Discuss the significance of histological modifications seen in the walls of the
respiratory passageways as one travels from the nares to the alveoli.
11. Discuss the mechanisms of nonspecific resistance that help to protect the respiratory
system.
Lung Structure
1. Identify and describe the respiratory passageways.
2. Describe the gross anatomical features and serous membranes associated with the
lungs.
3. Describe the structure of the alveolar wall.
4. Describe the blood and nerve supply to the lungs and associated structures.
Ventilation
1. Describe the relevant pressures involved in ventilation.
2. Discuss the pressure changes necessary for inspiration and expiration.
3. Compare and contrast how inspiration and expiration are achieved at rest with how
they can be increased during exertion.
4. Describe the nervous system control of ventilation.
5. Explain the roles of the Hering-Breuer reflex and the pneumotaxic center in
controlling respiration.
6. Describe the factors that affect ventilation rates.
7. Compare the measurable volumes and capacities of air exchanged during ventilation.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 81 Respiratory System
8. Define and explain the importance of Boyle’s law to respiratory physiology.
9. Explain how and why humidification of air as it enters the nasal cavity decreases the
partial pressure of oxygen.
10. Define eupnea, apnea, hyperpnea, dyspnea and tachypnea.
Gas Exchange and Transport
1. Define external and internal respiration.
2. Describe the mechanisms of gas exchange between alveolar air and blood.
3. Describe the factors that determine the rate of gas exchange between air and blood.
4. Define and explain the importance of Dalton’s law and Henry’s law to respiratory
physiology.
5. Calculate the partial pressure of oxygen near the summit of Mount Everest where
atmospheric pressure is only about 260 mm Hg given that the percentage of oxygen in
the air (~21%) does not change.
6. Assess the significance of the decrease in O 2 availability with increased altitude.
7. Relate changes in O2 availability to RBC production.
8. Explain the importance of O2 and CO2 partial pressure differences to external and
internal respiration.
9. Describe the mechanisms by which O 2 and CO2 are transported in the blood.
10. Explain the relationship between transport of oxygen and carbon dioxide.
11. Describe the role of gas transport and ventilation in control of pH.
12. Trace the pulmonary circulation from its beginning at the ventricle to its completion at
the atrium; indicate which vessels carry oxygenated blood and which carry
deoxygenated blood.
Disorders/Diseases
1. Differentiate between restrictive and obstructive pulmonary diseases
2. Describe the following disorders and diseases of the respiratory system:
a. Chronic obstructive pulmonary diseases
i. Emphysema
ii. Chronic bronchitis
b. Pleurisy
c. Infant respiratory distress syndrome (RDS)
d. Asthma
e. Cystic fibrosis
f. Pneumothorax
g. Lung cancer
h. Infectious diseases
i. Pneumonia
ii. Tuberculosis
iii. Bronchitis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 82 Respiratory System
See self quiz: http://vilenski.com/science/humanbody/hb_html/selftest/resp/index.html
See also A.D.A.M. Interactive Physiology – Cardiovascular System
* Anatomy Review: Respiratory Structures
* Pulmonary Ventilation
* Gas Exchange
* Gas Transport
* Control of Respiration
E. Lathrop-Davis / E. Gorski / S. Kabr hel 83 Respiratory System
E. Lathrop-Davis / E. Gorski / S. Kabr hel 84 Respiratory System
Topic 7: Respiratory System
I. Functions
A. Main function: exchange gases (CO2 and O2)
B. Other functions:
1. Aid acid-base balance (pH balance)
2. Produces sounds (vocalizations)
3. Remove neurotransmitters
4. Produce angiotensin II
5. Trap and dissolve small clots
II. Basic Processes Fig. 23.17, p. 860
A. Ventilation
B. External respiration
C. Blood gas transport
D. Internal respiration
III. Basic Organization
A. Conducting passageways Fig. 23.1, p. 836
1. Move air into and out of body but are not involved in actual
gas exchange
2. Include nose, pharynx, trachea, larynx, bronchi,
bronchioles, terminal bronchioles
B. Respiratory passageways
1. Involved in exchange of gases between air and blood
2. Include respiratory bronchioles, alveolar ducts, alveoli
C. Lung Anatomy Fig. 23.10, p. 848
1. Located in thoracic cavity lateral to mediastinum
2. Lungs consist of lobes (3 right; 2 left)
a. bronchopulmonary segments – sections of lobes
separated by connective tissue, supplied by artery, vein,
lymphatics, and tertiary (segmental) bronchi
b. lobule – smallest visible subdivision, served by large
bronchioles
3. Lung tissue
4. Hilus
E. Lathrop-Davis / E. Gorski / S. Kabr hel 85 Respiratory System
5. Serous membranes (See A&P I Unit II Tissues – Epithelial
Membranes)
a. visceral (= pulmonary) pleura
b. parietal pleura
c. pleura cavity
IV. Conducting Passageways
A. Nose and nasal cavity Fig. 23.2, p. 837; Fig. 23.3, p. 837
1. Functions:
a. serve as airway for ventilation
b. moisten, warm, filter air
c. resonate sounds produced for speech
d. house olfactory receptors
2. Special structures:
a. paranasal sinuses (See A&P I Lab Axial Skeleton)
b. nasal conchae
c. nasal septum
d. palate
1) hard (See A&P I Lab Axial Skeleton)
2) soft
B. Pharynx Fig. 23.3, pp. 837-838
1. Connects nose and mouth to larynx
2. Three “parts” distinguished by landmarks
a. nasopharynx
1) air passageway only
2) located posterior to nasal cavity, superior to soft
palate
3) contains openings to auditory (eustachian or
pharyngotympanic) tubes
4) contains pharyngeal tonsils (adenoids) (See Topic 5
Lymphatic System)
b. oropharynx
1) air and food
2) posterior to oral cavity, inferior to soft palate
3) lined with stratified squamous epithelium
4) contains lingual and palatine tonsils (See Topic 5
Lymphatic System)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 86 Respiratory System
c. laryngopharynx
1) air and food
2) inferior to oropharynx
3) lined with stratified squamous epithelium
C. Larynx Fig. 23.3, pp. 837-838; Fig. 23.4, p. 840
1. Opening into larynx is glottis (covered by epiglottis [elastic
cartilage] during swallowing)
2. Wall consists of pieces of hyaline cartilage including
thyroid cartilage, cricoid cartilage, arytenoid cartilages
3. True vocal cords
a. folds of mucosa containing elastic vocal ligaments that
vibrate to produce sound (tension controlled by
arytenoid cartilages)
b. sound production
1) vocal cords tightened during exhalation
2) air movement causes vibration of cords
3) pitch (frequency)
4) loudness
4. Vestibular folds
D. Trachea Fig. 23.5, p. 843
1. Patent (open) airway from larynx to level of T5 in chest
2. Contains 16-20 hyaline cartilage rings incomplete
posteriorly
3. Layers of trachea wall:
a. mucosa
b. submucosa
c. seromucous glands
d. adventitia
E. Bronchial Tree Fig. 23.7, p. 844
1. General trends
a. decrease and eventual loss of cartilage
b. gradual addition of smooth muscle to control diameter
c. epithelium becomes flatter
2. Primary bronchi
a. one to each lung
b. wall has cartilage with some smooth muscle
E. Lathrop-Davis / E. Gorski / S. Kabr hel 87 Respiratory System
c. lined with pseudostratified ciliated epithelium with
numerous goblet cells
3. Secondary bronchi
a. branches of primary bronchi serving lobes of lungs
b. walls with less cartilage and more smooth muscle
c. lined with pseudostratified ciliated epithelium in which
cell height is smaller
4. Tertiary bronchi
a. branches of secondary bronchi serving
bronchopulmonary segments
b. walls with irregular rings of cartilage and much more
smooth muscle
c. cells of pseudostratified ciliated epithelium lining very
short
5. Bronchioles
a. small branches of tertiary bronchi
b. walls primarily of smooth muscle with little or no
cartilage
c. lining of cuboidal epithelium
6. Terminal bronchioles
a. branches of bronchioles
b. lack cartilage, smooth muscle is scattered
c. lined with simple cuboidal epithelium
V. Respiratory Passageways (Respiratory Zone) Fig. 23.8, p. 845
A. Respiratory bronchioles
1. Smallest and thinnest of air passageways leading to
respiratory surfaces of lung
2. Lined with low simple cuboidal epithelium
B. Alveolar ducts
C. Alveolar sacs
D. Alveoli
1. Walls = “Respiratory Membrane”
2. Walls act as barrier to diffusion of respiratory gases (CO 2
and O2)
3. Adjacent alveoli joined by alveolar pores
E. Lathrop-Davis / E. Gorski / S. Kabr hel 88 Respiratory System
4. Walls consist of:
a. alveolar endothelium
1) type I cells
2) type II cells
b. basal lamina
c. capillary endothelium
VI. Blood and Nerve Supply to Lungs
A. Vessels and Nerves enter and leave through hilus
B. Nerve supply
1. Pulmonary plexuses – provide ANS innervation to smooth
muscle of bronchi
a. sympathetic innervation Fig. 14.5, p. 519
b. parasympathetic innervation Fig. 14.4, p. 517
C. Blood supply
1. Pulmonary circulation
a. carries blood to respiratory surfaces of lung for gas
exchange with air in alveoli
b. pulmonary arteries capillaries pulmonary veins
2. Bronchial circulation
a. carries blood to all lung tissues except alveoli
b. aorta bronchial arteries capillaries bronchial
veins
c. bronchial veins form so many anastomoses that most
blood returns through pulmonary veins
VII. Ventilation Fig. 23.13, p. 852
A. Movement of air into/out of lungs
1. Inspiration
2. Expiration
B. Air flow = pressure difference / resistance
a. air moves from higher pressure to lower pressure
b. pressure gradient moves gases between nose/mouth
and terminal bronchioles
c. between terminal bronchioles and alveoli, gas movement
is driven by diffusion
E. Lathrop-Davis / E. Gorski / S. Kabr hel 89 Respiratory System
C. Pressure
1. Important pressures
a. atmospheric pressure (P A)
b. intrapleural (intrathoracic) pressure
1) always less than intrapulmonary pressure by about 4
mm Hg
2) if intrapleural pressure > atmospheric pressure,
lungs collapse
c. intrapulmonary (intra-alveolar) pressure (PL)
2. Boyle’s Law
a. volume and pressure are inversely related
1) decreased volume (V) increased pressure
2) increased volume (V) decreased pressure
b. based on Boyle’s law:
1) for inspiration: PL < PA
2) for expiration, PL > PA
3. Processes of pressure changes for ventilation Fig. 23.13, p. 852
Inspiration Expiration
Diaphragm and/or external intercostal Diaphragm and external intercostal
muscles contract (innervated by muscles relax (passive process) and
phrenic and intercostal nerves, lungs recoil
respectively)
Thoracic volume increases Thoracic volume decreases
Intrapleural pressure decreases Intrapleural pressure increases
Lungs expand into lower pressure Lungs compressed by increased
thoracic (pleural) cavity pressure in thoracic (pleural cavity)
Intrapulmonary pressure decreases Intrapulmonary pressure increases
Air moves in Air moves out
a. expiration is normally passive
b. “forced” air movements
1) forced expiration
i. increased intrapleural pressure beyond normal
breathing
ii. muscles
(a) abdominal muscles* – external and internal
obliques, transverses abdominus
E. Lathrop-Davis / E. Gorski / S. Kabr hel 90 Respiratory System
(b) thoracic muscles – internal intercostals,
latissimus dorsi, quadratus lumborum
2) forced inspiration
i. decreased intrapleural pressure beyond normal
breathing
ii. pectoralis minor, scalenes, sternocleidomastoid
muscles
c. factors promoting lung expansion for inspiration
1) compliance
2) surface tension caused by pleural fluid (creates
negative intrapleural pressure)
i. excess fluid removed by lymphatic system
ii. failure to remove fluid increases intrapleural
pressure
d. factors promoting lung compression for expiration
1) alveolar fluid surface tension
i. surfactant
ii. respiratory distress syndrome (hyaline
membrane disease of the newborn)
2) elasticity
emphysema
D. Resistance to Airflow Fig. 23.15, p. 854
1. Opposes movement of flow into/out of lungs
2. Related to size (diameter and length) of passageway and viscosity of “fluid”
a. resistance (length of tube x viscosity of fluid) / radius4
b. greatest in medium-sized bronchioles
3. Factors increasing resistance:
a. bronchoconstriction
1) parasympathetic response to inhaled irritants
2) acetylcholine administration
3) decreased PCO2
b. other factors:
1) solid obstructing tumors
2) mucus accumulation
3) inflammation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 91 Respiratory System
4. Factors decreasing resistance:
a. bronchodilation
1) sympathetic innervation
2) epinephrine administration
3) increased PCO2
E. Regulation of ventilation
1. Brain centers
a. respiratory center
1) located in medulla oblongata
2) consists of:
i. inspiratory center (dorsal respiratory group or
DRG)
ii. expiratory center (ventral respiratory group or
VRG)
3) mechanism of control: Fig. 23.24, p. 868
i. active DRG sends impulses to diaphragm via
phrenic nerve (cervical plexus) and/or external
intercostals muscles via intercostals nerves to
stimulate contraction (also sends inhibitory
impulses to VRG)
ii. after about 2 seconds, DRG becomes inactive,
expiration occurs as inspiratory muscles relax
iii. after about 3 more seconds, DRG becomes
active again
b. pneumotaxic center located in pons inhibits DRG leading
to shortened breaths increases breathing rate (e.g.,
panting)
c. apneustic center – hypothetical center in pons that may
prolong inspiration by stimulating DRG
2. Factors affecting ventilation rates Fig. 23.25, p. 869
a. pulmonary irritants – chemoreceptors in lungs detect
air-borne chemicals and send impulses via Vagus nerve
efferent parasympathetic impulses cause
vasoconstriction, efferent somatic impulses result in
coughing or sneezing
b. Hering-Breuer (inflation) reflex – stretch receptors in
visceral pleura and conducting portions of airways
E. Lathrop-Davis / E. Gorski / S. Kabr hel 92 Respiratory System
respond to inflation of lungs and send afferent impulses
via Vagus nerve inhibit DRG
c. cortical controls – conscious control over skeletal
muscles involved in inspiration and expiration
d. hypothalamus – influences medullary centers in
response to emotions (e.g., pain, fear, anger) or
increased body temperature
e. chemical controls Fig. 23.25, p. 869
1) sensed by peripheral chemoreceptors in aorta and
carotid arteries and by central chemoreceptors in
medulla
2) PCO2 – normal arterial blood ~ 40 mm Hg + 3 mm Hg
i. peripheral chemoreceptors not very sensitive to
arterial PCO2
ii. central chemoreceptors respond to changes in
PCO2 (pH changes)
(a) CO2 diffuses readily across membranes
(enters CSF)
(b) increased PCO2 increased H + stimulates
receptors increase depth (and rate) of
breathing = hyperventilation
(c) effect of PCO2 works even when arterial blood
pH and PO2 are normal
(d) low PCO2 decreased H+ slower breathing
(hypoventilation)
3) PO2
i. normal arterial blood ~ 105 mm Hg
ii. respiratory center less sensitive to P O2
iii. peripheral chemoreceptors sensitive to P O2
stimulated when PO2 falls below 60 mm Hg
4) pH
i. normal arterial pH ~ 7.4
ii. decreased arterial pH stimulates peripheral
receptors resulting in increased ventilation even
if PCO2 and PO2 are normal
E. Lathrop-Davis / E. Gorski / S. Kabr hel 93 Respiratory System
F. Other Terms
1. Eupnea
2. Dyspnea
3. Apnea (e.g., sleep apnea)
4. Hypopnea
5. Hyperpnea
6. Tachypnea
VIII. External and Internal Respiration and Gas Transport Fig. 23.17, p. 860
A. Overview
1. External Respiration
2. Gas Transport
3. Internal Respiration
B. External/internal respiration – basic principles
1. Dalton’s law of partial pressures
a. pressure exerted by a gas in a mixture is directly
proportional to the percentage of that gas in the
mixture
1) e.g., if O2 = 20.9% of air at sea level where total gas
pressure = 760 mm Hg, PO2 = 20.9% x 760 mm Hg =
159 mm Hg
b. approximate percentages of gases from sea level to
about 300,000 ft.
Gas Contribution
N2 79.6%
O2 20.9%
CO2 0.04%
H2O 0.46%
c. total pressure decreases with altitude, therefore, P O2
decreases
See
http://www.udel.edu/Biology/dion/SicknessComments.h
tml for the table that includes alveolar oxygen levels at
different altitudes
E. Lathrop-Davis / E. Gorski / S. Kabr hel 94 Respiratory System
2. Henry’s law
a. when a mixture of gases comes into contact with a
liquid, individual gases will diffuse into the liquid in
proportion to their partial pressures
3. Factors governing diffusion rate
gas solubility X membrane surface area X gradient X temperature
membrane thickness X square root of molecular wt.
a. gas solubility in liquid
b. molecular weight
c. temperature of the liquid
d. membrane thickness
1) capillary and alveolar walls
2) emphysema
e. membrane surface area
1) lung cancer
2) emphysema
f. partial pressure gradient*
C. External Respiration:
1. Partial pressures in alveoli different from atmospheric
2. Reasons for difference
a. humidification of inhaled air
b. gas movements
1) increases alveolar PCO2
2) decreases alveolar PO2
c. mixing of old and new air
3. Gas Movements
a. O2 loading (into blood)CO2 unloading (out of blood)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 95 Respiratory System
4. Ventilation-Perfusion Couplingcirculatory system works in
coordination with respiratory system to maximize
effectiveness of exchange
b. PO2 – affects arteriolar diameter
1) low airflow decreased PO2 in airway
vasoconstriction of pulmonary arterioles
2) high airflow increased PO2 in airway
vasodilation of pulmonary arterioles
c. PCO2 – affects bronchiolar diameter
1) low airflow increased PCO2 in airway
bronchodilation
2) high airflow decreased PCO2 in airway
bronchoconstriction
D. Blood gas transport
1. Oxygen transport
a. ~98.5 % carried attached to iron of hemoglobin (See
Topic 1 Blood)
1) deoxyhemoglobin (HHb) + 4 O 2 Hb(O2 )4
b. ~ 1.5% carried as dissolved oxygen in plasma (exerts
partial pressure)
c. oxygen saturation curve Fig. 23.20, p. 863; Fig. 23.21, p. 864
1) demonstrates effect of P O2 and cooperative binding
2) systemic venous blood still > 70% saturated
3) saturation depends on:
i. PO2
ii. PCO2
iii. temperature
iv. blood bis-phosphoglycerate (BPG) levels
E. Lathrop-Davis / E. Gorski / S. Kabr hel 96 Respiratory System
v. pH
(a) Bohr effect
(b) carbonic (H 2CO3) and lactic acids contribute
to lowering pH
4) NO (nitric oxide)
i. secreted by endothelial cells of blood vessels
and lungs
ii. causes vasodilation of pulmonary and tissue
capillaries and enhanced gas exchange
5) dissociation tied to needs of hard working cells
Factors Affecting Favoring Hb-O2 Favoring Hb-O2
Association Association Dissociation
Temperature
PO2
PCO2
pH
BPG
2. Carbon dioxide transport Fig. 23.22, p. 866
a. 7-10% carried as dissolved carbon dioxide
b. 20-30% carried attached to globin part of hemoglobin
(carbaminohemoglobin)
c. ~ 70% converted to bicarbonate ions (HCO3 -) for
transport in plasma
1) CO2 + H 2 O H 2 CO3 H+ + HCO3 -
2) reaction is spontaneous, but slow in plasma
3) rapid in RBCs due to presence of carbonic anhydrase
4) chloride shift – exchange of ions (Cl- and HCO3 -)
between plasma and RBCs
d. Haldane effect – reduced Hb bonds to CO2 more
efficiently than oxyhemoglobin
1) more CO2 carried when O2 is low
2) as CO2 increases, O2 dissociation increases Fig. 23.23, p. 867
E. Internal Respiration
1. Gas Movements
E. Lathrop-Davis / E. Gorski / S. Kabr hel 97 Respiratory System
a. O2 enters tissues from blood
b. CO2 leaves tissues to enter blood
2. Factors affecting movements
a. surface area for exchange
1) size of capillary bed[s]
2) varies
b. partial pressure gradient
c. rate of blood flow
IX. Respiratory Disorders
A. Restrictive Pulmonary Disease
1. Diseases in which lung volume is reduced
2. Results in reduced total lung capacity, vital capacity or
resting lung volume
3. Causes include:
a. changes to lung tissue that reduce volume
b. changes to pleurae, chest wall or respiratory
musculature or nerves that reduce compliance
B. Chronic obstructive pulmonary disease (COPD)
1. Chronic diseases in which breathing is difficult and gets
progressively worse, coughing and pulmonary infection are
common
2. Ventilation is impaired and ability to exhale rapidly and
forcefully is diminished
3. Patient eventually develops respiratory failure
4. May be caused by long-term smoke inhalation
5. COPDs include:
E. Lathrop-Davis / E. Gorski / S. Kabr hel 98 Respiratory System
a. Cystic fibrosis (CF) – congenital defect of Cl- transport
protein in plasma membrane; results in overproduction
of thick mucus reducing usable diameter of airways
b. Emphysema – breakdown of intra-alveolar walls
resulting in permanent enlargement of alveoli
(decreased surface area); lungs become fibrous and
inelastic
c. Chronic bronchitis – chronic irritation and infection of
bronchi
C. Inflammatory Respiratory Disorders
1. Pleurisy – inflammation of pleural membranes results either
in decreased fluid (increases friction) or fluid build up
(increased intrathoracic = intrapleural pressure)
2. Asthma inflammation of airways usually as an allergic
reaction to airborne particles; may be made worse by
autonomic factors, infection (inflammation), exercise, cold;
results in coughing, sneezing, dyspnea, wheezing, tightness
in chest
D. Infant Respiratory Distress Syndrome (RDS)
1. a.k.a., hyaline membrane disease or HMD
2. collapse of alveoli on exhalation caused by lack of
sufficient surfactants
E. Infectious diseases
1. Pneumonia – viral or bacterial infection of lungs
2. Bronchitis – viral or bacterial infection of bronchi
3. Tuberculosis – – bacterial infection caused by
Mycobacterium tuberculosis
F. Pneumothorax – presence of air in intrapleural space, as from a
puncture wound
G. Lung cancer – cancerous tumor growth; often related to
inhaled carcinogens (as are found in tobacco smoke)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 99 Respiratory System
TOPIC 8
Digestive System
Chapter 24, pp. 888-939
Objectives
Introduction
1. List the components and functions of the digestive system.
2. Differentiate between the organs of the alimentary canal and accessory digestive
organs.
3. List and briefly describe the major processes that occur during digestion.
4. Describe the location and function of the peritoneum and the peritoneal cavity.
5. Define retroperitoneal and name the retroperitoneal digestive organs.
6. Describe the histology and general function of each of the four layers of the
alimentary canal.
7. Diagram the flow of blood supply to the digestive system including the hepatic portal
system.
8. Describe the innervation of the digestive system.
Anatomy of the Digestive System
1. Trace the flow of food through the alimentary canal from the oral oriface to the anus.
2. Describe the gross anatomy, histology, special features, and basic function of each
organ of the alimentary canal.
3. Trace the histological changes (including epithelial and muscular modifications) in the
wall of the alimentary canal from the oral cavity to the anus.
4. Describe the gross anatomy, histology, special features, and basic function of each
accessory organ.
5. Indicate on your flow chart where the products of the accessory organs enter the
alimentary canal.
6. Describe the composition and functions of saliva.
Physiology of Digestion
1. Describe and explain the significance of the various movement processes within the
digestive tract.
2. List and describe the digestive processes that occur in the mouth, pharynx and
esophagus.
3. Define deglutition and describe its control.
4. Describe the composition, secretion, and functions of the components of gastric juice.
5. Diagram the control of gastric activity.
6. List and describe the digestive processes that occur in the stomach.
7. List and describe the digestive processes that occur in the small intestine.
8. Diagram the control of intestinal activity.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 100 Digestive System
9. Describe the composition, secretion, and functions of the components of intestinal
juice.
10. Describe the composition, secretion, and functions of the components of pancreatic
juice.
11. Diagram the control of pancreatic juice secretion.
12. Describe the endocrine role of the pancreas.
13. Describe the composition and functions of the components of bile.
14. Diagram the control of bile formation, secretion and release.
15. Describe the digestive processes that occur in the large intestine.
16. Explain the significance of the resident intestinal flora.
17. Describe the control of defecation.
18. List enzymes involved in chemical digestion of proteins, carbohydrates, lipids and
nucleic acids.
19. Analyze and discuss the causes and effects of pH changes on the activity of the
various digestive enzymes.
20. Diagram the chemical digestion of carbohydrates, proteins, lipids and nucleic acids
including the enzymes used to digest each.
21. Describe the process of absorption of nutrients throughout the alimentary canal.
22. Indicate on your flow chart (# 1 under Anatomy above) where chemical digestion and
absorption of carbohydrates, proteins, lipids and nucleic acids takes place.
Disorders
Describe the following disorders of the digestive system.
1. Mumps
2. Heart burn
3. Hiatus hernia
4. Esophageal ulcer
5. Gastritis
6. Gastric (peptic) ulcers
7. Emesis
8. Hepatitis
9. Cirrhosis
10. Jaundice
11. Obstructive jaundice
12. Gall stones
13. Pancreatitis
14. Appendicitis
15. Diarrhea
16. Constipation
17. Hemorrhoids
18. Colitis
19. Diverticulosis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 101 Digestive System
20. Diverticulitis
21. Crohn’s disease
E. Lathrop-Davis / E. Gorski / S. Kabr hel 102 Digestive System
E. Lathrop-Davis / E. Gorski / S. Kabr hel 103 Digestive System
Topic 8: Digestive System
I. Digestive System Overview
A. Functions
1. Provide nutrients in a usable form
2. Eliminate unusable wastes
B. Two main groups of organs: Fig. 24.1, p. 888
1. Alimentary canal (a.k.a. Gastrointestinal tract)
a. tube through which food passes
b. responsible for digestion and absorption of food
c. mouth, pharynx, esophagus, stomach, small intestines,
large intestines
2. Accessory organs
a. organs, glands and structures which aid digestion but
are not part of GI tract itself
b. teeth, tongue, salivary glands, pancreas, liver, gall
bladder
C. Processes of Digestion Fig. 24.2, p. 889
1. Ingestion
2. Mechanical digestion
3. Chemical digestion
4. Propulsion
5. Absorption
6. Defecation
D. Peritoneum Fig. 24.5, p. 891
1. Serous membrane Fig. 24.30, p. 929
a. parietal peritoneum
1) retroperitoneal organs
b. visceral peritoneum
1) mesenteries
2) intraperitoneal organs
2. Peritoneal cavity
3. Peritonitis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 104 Digestive System
E. Blood Supply
1. Splanchnic circulation
a. Celiac trunk Fig. 20.22, p. 761
1) common hepatic artery (liver; gall bladder; stomach;
duodenum)
2) left gastric artery (stomach; inferior esophagus)
3) splenic artery (spleen; stomach; pancreas)
b. Superior mesenteric artery (almost entire small
intestine; pancreas; most of large intestine)
c. Inferior mesenteric artery (large intestine)
2. Hepatic circulation Fig. 20.22, p. 761
a. hepatic portal system
1) gastric vein
2) superior mesenteric vein
3) splenic vein
4) inferior mesenteric vein
b. venous blood from hepatic portal system mixes with
arterial blood (hepatic artery) in liver
c. hepatic veins
F. Alimentary Canal Histology Fig. 24.6, p 93
1. Mucosa – mucous membrane lining gut
a. epithelium
1) type varies depending on location
i. stratified squamous epithelium found in mouth,
esophagus and anal canal
ii. simple columnar epithelium found in stomach and
intestines
2) secretes mucus, digestive enzymes, hormones
3) provides intact barrier to protect against entry of
bacteria
b. lamina propria
1) areolar connective tissue
2) blood capillaries nourish epithelium, absorb and
transport digested nutrients
E. Lathrop-Davis / E. Gorski / S. Kabr hel 105 Digestive System
3) lymphatic capillaries provide drainage for
interstitial fluid and transport fats to venous
circulation
c. muscularis mucosae
1) smooth muscle
2) local movement
3) holds mucosa in folds (small intestine)
2. Submucosa
a. dense connective tissue superficial to mucosa
b. highly vascularized
c. many lymphatic vessels
d. lymph nodules
e. mucosa-associated lymphatic tissue (MALT) present,
especially in small (Peyer’s patches) and large intestines
3. Muscularis externa (muscularis) Fig. 24.3, p. 890
a. two layers in most organs (3 in stomach)
1) circular layer
2) longitudinal layer
b. peristalsis
c. segmentation
4. Serosa
a. visceral peritoneum
b. adventitia
G. Nerve supply
1. Enteric nervous system – intrinsic nerve plexuses
a. enteric neurons – neurons able to act independently of
the central or peripheral nervous system; communicate
with each other to control GI activity
b. two main enteric plexuses:
1) submucosal nerve plexus – regulates glands in
submucosa and smooth muscle of muscularis
mucosae
2) myenteric nerve plexus – regulates activity of
muscularis externa (with aide of submucosal nerve
plexus)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 106 Digestive System
2. Central nervous system control
a. enteric nerve plexuses linked to CNS by visceral
afferent (sensory) fibers
b. autonomic nervous system
1) parasympathetic outflow generally increases
activity
2) sympathetic outflow generally decreases activity
II. Mouth, Pharynx, Esophagus and Associated Structures
A. Mouth = oral cavity
1. Gross anatomy
a. oral oriface
b. continuous with oropharynx
c. lips and cheeks keep food in oral cavity
2. Histology
a. mucosa
b. submucosa
c. muscularis externa
3. Palate
a. hard palate (See A&P I Lab Axial Skeleton)
1) palatine process of maxilla
2) palatine bones
b. soft palate
1) muscle only (no bone)
2) prevents food from entering nasopharynx during
swallowing
c. Arches
1) palatoglossal arch
2) palatopharyngeal arch
i. fauces
ii. palatine tonsils (See Topic 5 Lymphatic System)
4. Tongue
a. lingual tonsil (See Topic 5 Lymphatic System)
b. taste buds
c. bolus
E. Lathrop-Davis / E. Gorski / S. Kabr hel 107 Digestive System
d. tongue muscles (See A&P I Unit VI “Brain and Cranial
Nerves” for innervation
1) intrinsic muscles
2) extrinsic muscles
5. Salivary glands and saliva
a. two groups of salivary glands
1) intrinsic glands = buccal glands
2) extrinsic glands – 3 pairs
i. parotid glands (glossopharyngeal [IX])
ii. sublingual glands (facial [VII])
iii. submandibular glands (facial [VII])
b. saliva
1) mucous cells produce mucus (less common)
2) serous cells produce watery saliva; composition:
i. 97-99.5% water
ii. slightly acidic (pH ~ 6.8)
iii. electrolytes (ions such as NA+ , K+ , CL-, PO4=,
HCO3-)
iv. metabolic wastes (urea, uric acid)
v. proteins, including:
(a) mucin - lubricant
(b) lysozyme – antibacterial
(c) IgA – prevents antigens from attaching to
epithelium
(d) defensins - antibiotic and chemotactic
(e) salivary amylase – starch digestion
c. control of salivation (See A&P I Unit IX Autonomic
Nervous System)
1) sympathetic division
i. mucin-rich saliva
ii. inhibition of salivation
2) parasympathetic division
i. receptors:
(a) chemoreceptors
(b) baroreceptors
E. Lathrop-Davis / E. Gorski / S. Kabr hel 108 Digestive System
(c) send messages to salivatory nuclei in pons
and medulla
ii. psychological control
iii. irritation to lower GI tract
iv. nerves
(a) Facial (VII; to submandibular, sublingual
salivary glands)
(b) Glossopharyngeal (IX; to parotids)
6. Teeth
a. lie in alveoli of mandible and maxilla (See A&P I Lab
Axial Skeleton)
b. primary dentition = deciduous teeth (20 milk or baby
teeth)
c. permanent dentition = adult teeth (32)
1) incisors (central and lateral)
2) canines
3) bicuspids = premolars
4) molars
i. first molars
ii. second molars
iii. third molars
(a) “wisdom teeth”
(b) may become impacted as grow in
d. tooth structure
1) crown - covered by enamel (hardest substance in
body); underlain with dentin
2) neck
3) root
i. cementum
ii. dentin
iii. pulp cavity / root canal
B. Pharynx (See Topic 7 Respiratory System)
1. Only oropharynx and laryngopharynx are involved in
digestion (nasopharynx is only respiratory)
2. Lined with stratified squamous epithelium
E. Lathrop-Davis / E. Gorski / S. Kabr hel 109 Digestive System
3. mucus-producing glands - mucus lubricates food
4. Skeletal muscle in wall - somatic reflexes move food
quickly past laryngopharynx
5. No serosa or adventitia
C. Esophagus
1. Runs from laryngopharynx through mediastinum to stomach
2. All 4 layers present in wall
a. mucosa – consists of stratified squamous epithelium
with mucus producing glands (produce mucus)
b. submucosa – mucus-secreting esophageal glands
c. muscularis – changes type from skeletal muscle to
smooth muscle
d. adventitia – dense connective tissue covering
3. Special structures
a. upper esophageal sphincter – controls movement into
esophagus
b. esophageal hiatus – opening in diaphragm
c. gastroesophageal (cardiac) sphincter
1) thickening of smooth muscle of inferior esophagus
2) aided by diaphragm
3) helps prevent reflux of acidic gastric juice
4. Esophageal disorders
a. heartburn
b. hiatus hernia
c. esophageal ulcer
D. Digestive processes in mouth, pharynx and esophagus
1. Ingestion
2. Mechanical digestion
a. mastication by teeth
b. formation of bolus
3. Chemical digestion by salivary amylase
a. produced by salivary glands
b. breaks starch and glycogen into smaller fragments
(including maltose if left long enough)
c. activity continues until reaches acid in stomach
E. Lathrop-Davis / E. Gorski / S. Kabr hel 110 Digestive System
4. Absorption – essentially none (except some drugs, e.g.,
nitroglycerine)
5. Movement
a. formation of bolus
b. deglutition (swallowing) Fig. 24.13, p. 904
1) voluntary in oral cavity (buccal phase)
2) reflexive in pharynx
3) involuntary peristalsis where smooth muscle is found
III. Stomach Fig. 24.14, p. 905
A. Gross anatomy
1. Cardiac region
2. Fundus
3. Body
a. greater curvature
b. lesser curvature
4. Pyloric region
a. pyloric sphincter
B. Histology
1. Mucosa
a. simple columnar epithelium
b. rugae
2. Submucosa
3. Muscularis – 3 layers create mixing waves in addition to
peristalsis
a. longitudinal layer
b. circular layer
c. oblique layer
4. Serosa
C. Microscopic anatomy
1. goblet cells
2. Gastric pits
a. tight junctions between epithelial cells
b. gastric glands secrete gastric juice
E. Lathrop-Davis / E. Gorski / S. Kabr hel 111 Digestive System
1) mucous neck cells secrete bicarbonate-rich mucus
2) parietal (oxyntic) cells secrete:
i. HCl
ii. intrinsic factor
3) chief (zymogenic) cells secrete:
i. pepsinogen pepsin
ii. minor amounts of lipases
4) enteroendocrine cells – release hormones and
hormone-like products into the lamina propria where
they are picked up by blood and carried to other
digestive organs
i. gastrin – generally stimulatory
(a) stimulates gastric cell activity, especially H+
secretion
(b) stimulates gastric emptying
(c) stimulates contraction of small intestine
(d) relaxes ileocecal valve
(e) stimulates mass movement (large intestine)
ii. histamine – stimulates H + secretion
iii. somatostatin (also secreted by small intestine in
larger amounts) – generally inhibitory
(a) inhibits gastric secretion, motility and
emptying
(b) inhibits pancreatic secretion
(c) inhibits activity in small intestine
(d) inhibits contraction of gall bladder
D. Digestive Processes in Stomach
1. Mechanical digestion - mixing waves help break food into
smaller particles
2. Chemical digestion – produces chyme (pH ~ 2)
a. HCl secreted by parietal cells breaks some bonds and
activates pepsin
b. pepsin
1) from pepsinogen secreted by chief cells
2) protease
c. rennin – acts on milk proteins (casein)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 112 Digestive System
3. Movements:
a. mixing waves
b. peristalsis
4. Absorption – limited to lipid soluble substances
a. alcohol
b. aspirin
c. some other drugs
E. Regulation of Gastric Secretion Fig. 24.16, p. 910
1. Hormonal control
a. gastrin stimulates secretion
b. somatostatin, gastric inhibitory peptide (GIP) and
cholecystokinin (CCK) inhibit secretion
2. Neural control:
a. autonomic control (CNS: ANS)
1) parasympathetic impulses via Vagus (X) nerve
increase activity
2) sympathetic impulses decrease activity
b. local enteric nerve reflexes
1) distension of stomach activates stretch receptors
resulting in stimulation of stomach activity
2) distension of duodenum results in reflexive
inhibition of stomach activity
3. Stimulation of gastric activity
a. cephalic phase –Vagus (X) nerve increases activity
1) sight, smell and/or thought of food
2) stimulation of taste buds and smell receptors
b. gastric phase
1) stomach distension activates stretch receptors that
involve CNS (vagus nerve) and local enteric reflexes
2) food chemicals (especially peptides and caffeine),
and rising pH activate chemoreceptors involving
CNS
c. intestinal phase – presence of low pH and partially
digested foods in duodenum when stomach begins to
empty causes release of intestinal gastrin, which
stimulates gastric secretion and motility
E. Lathrop-Davis / E. Gorski / S. Kabr hel 113 Digestive System
4. Inhibition of gastric activity
a. cerebral
1) lack of appetite or depression decrease
parasympathetic output
2) emotional upset increases sympathetic output
b. stomach
1) excessive acidity (<pH2)
2) somatostatin
c. duodenum – distension; presence of fatty, acidic,
hypertonic chyme; presence of irritants or partially
digested food – inhibit gastric activity through:
1) enterogastric reflexes
2) inhibitory intestinal hormones (enterogastrones)
including somatostatin, GIP and CCK
F. Gastric disorders
1. Gastritis – inflammation of the gastric mucosa
2. Gastric ulcers
a. Helicobacter pylori infections associated with ~90% of
all ulcers (uncertain as to whether it is causitive agent)
b. non-infectious ulcers associated with persistent
inflammation
3. Emesis = vomiting
a. usually caused by:
1) extreme stretching of stomach or small intestine,
or
2) presence of irritants in stomach (e.g., bacterial
toxins, alcohol)
b. emetic center initiates impulses to:
1) contract abdominal muscles
2) relax cardiac sphincter
3) raise soft palate
c. excessive vomiting results in dehydration and metabolic
alkalosis (See Topic 11 Fluid, Electrolyte and Acid/Base
Balance)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 114 Digestive System
IV. Small Intestine
A. Gross structure
1. Diameter ~ 2.5 cm (~ 1 inch)
2. Length ~ 2-4 m (8-13 ft) in a living adult human (6-7 m [20-
21feet] in a cadaver because muscle is relaxed)
3. Small intestine designed for secretion (especially proximal
end) and absorption
a. site of most chemical digestion
b. site of most absorption
4. pH between 7 and 8
B. Three areas: Fig. 24.21, p. 916
1. Duodenum Fig. 24.20, p. 915
st
a. 1 25 cm
b. receives chyme from stomach
c. hepatopancreatic ampulla
1) union of common bile duct and pancreatic duct
2) opens via major duodenal papilla
3) hepatopancreatic sphincter (sphincter of Oddi)
controls entry of fluid from ampulla
d. duodenal (Brunner’s) glands
2. Jejunum extends from duodenum to ileum
3. Ileum
a. extends from jejunum to large intestine
b. ileocecal valve
C. Innervation Fig. 14.4, p. 517; Fig. 14.5, p. 519
1. Parasympathetic impulses supplied by Vagus (X) nerve
stimulate activity
2. Sympathetic impulses supplied by thoracic splanchnic
nerves inhibit activity
3. Enteric nerves
D. Blood supply Fig. 20.22, p. 761; Fig. 20.27, p. 771
1. Arteries:
a. common hepatic artery - serves duodenum
b. superior mesenteric artery - serves almost all of small
intestine
E. Lathrop-Davis / E. Gorski / S. Kabr hel 115 Digestive System
2. Veins - superior mesenteric vein
E. Special anatomical features Fig. 24.21, p. 916; Fig. 24.22, p. 917
1. Plicae circularis
a. circular folds
b. deep, permanent folds of mucosa and submucosa
c. force chyme to spiral through lumen
1) mixes chyme with intestinal juice
2) slows movement
2. Villi
a. finger-like projections of mucosa (over 1 mm tall)
b. contain:
1) blood capillary bed
2) lacteal
3) smooth muscle allows villus to shorten and lengthen
(alternating contraction and relaxation)
i. increases contact between villus and “soup” in
lumen
ii. “milks” lacteal
3. Microvilli
a. extensions of cell membrane
b. called brush border
c. functions:
1) secrete brush border enzymes
2) increase surface area for absorption
F. Histology – 4 layers:
1. Mucosa
a. renewed every 3-6 days
b. simple columnar epithelium
1) goblet cells
2) absorptive cells
i. tight junctions
ii. microvilli
c. lamina propria
E. Lathrop-Davis / E. Gorski / S. Kabr hel 116 Digestive System
d. intestinal crypts (crypts of Lieberkuhn)
1) most cells secrete intestinal juice
2) Paneth cells secrete lysozyme (antibacterial)
2. Submucosa
a. Peyer’s patches (See Topic 5 Lymphatic System)
b. duodenal (Brunner’s) glands - secrete alkaline mucus
rich in bicarbonate
3. Muscularis
a. two layers of smooth muscle create two kinds of
movement
1) peristalsis moves chyme through intestine
2) segmentation mixes chyme with intestinal juice -
chyme moves between segments a few cm at a time
b. intrinsic control in longitudinal muscle (intrinsic
pacemaker cells)
c. intensity altered by nervous system and hormones
4. Serosa (visceral peritoneum)
a. mesenteries
b. intraperitoneal organs
G. Digestive processes
1. Mechanical digestion – bile salts secreted by liver (stored
in and released from gall bladder) emulsify fat globules
2. Chemical digestion Fig. 24.33, p. 933
a. lipid digestion Fig. 2.14, p. 48
1) pancreatic lipase
2) most common lipids are neutral fats (triglycerides)
i. glycerol + 1 fatty acid = monoglyceride
ii. glycerol + 2 fatty acids = diglyceride
iii. glycerol + 3 fatty acids = triglyceride
3) triglycerides cleaved into glycerol and fatty acids or
monoglycerides and fatty acids
E. Lathrop-Davis / E. Gorski / S. Kabr hel 117 Digestive System
b. protein digestion Fig. 2.17, p. 52
1) pancreatic proteases: trypsin, chymotrypsin and
carboxypolypeptidase
i. secreted as inactive precursors (trypsinogen,
chymotrypsinogen, and procarboxypolypeptidase,
respectively)
ii. cleave large proteins into small peptides
2) intestinal proteases
i. include aminopeptidase, carboxypeptidase,
dipeptidase
ii. cleave small peptides into amino acids
c. carbohydrate digestion Fig. 2.13, p. 46
1) starches - cleaved into short chains
(oligosaccharides) and disaccharides by pancreatic
amylase secreted by pancreas
2) disaccharides hydrolyzed by intestinal enzymes:
i. maltase – cleaves maltose
ii. lactase – cleaves lactose
iii. sucrase – cleaves sucrose
d. nucleic acid digestion Fig. 2.22, p. 58
1) pancreatic nucleases – cleave nucleic acids into
nucleotides
2) nucleosidases and phosphatases – cut nucleotides
into sugars, phosphates and bases
3. Absorption
a. moves nutrients from lumen into cells, thence into
interstitial fluid to blood or lymph
b. carbohydrates – absorbed as monosaccharides
1) cotransport with Na+ (glucose and galactose)
2) facilitated transport (fructose)
c. proteins – absorbed as amino acids
1) cotransport with Na+
2) proteins rarely taken up intact (absorbed peptides
may cause food allergies)
d. nucleic acids - actively absorbed as components: ribose,
phosphate, nitrogen bases
E. Lathrop-Davis / E. Gorski / S. Kabr hel 118 Digestive System
e. lipids Fig. 24.36, p. 937
1) combine with bile salts to form micelles
2) absorbed passively through lipid bilayer as
monoglycerides, fatty acids and glycerol
3) combine with proteins within cell to form
chylomicrons, which are then released into
interstitial fluid
4) chylomicrons enter lymph through lacteals
(lymphatic capillaries) in villi and are transported to
subclavian veins
f. Vitamins
1) fat-soluble vitamins (DAKE) incorporated into
micelles and absorbed in same manner as fats
(passively through lipid bilayer)
2) water-soluble vitamins (C, B complex)
i. mostly absorbed by diffusion
ii. exception is B1 2 , which must bind to intrinsic
factor produced in stomach to be actively
absorbed in ileum (recognition of B12 -intrinsic
factor complex by receptors in plasma
membrane of cells triggers active receptor-
mediated endocytosis)
g. electrolytes
1) most actively absorbed throughout small intestine
i. absorption based on how much is in food
ii. Na+/K+ pump plays role
iii. K+ passively absorbed based on gradient
2) iron (Fe) and calcium (Ca) only absorbed in duodenum
i. depends on needs of body
ii. iron actively transported into cells where it
becomes bound to ferritin
iii. calcium absorption regulated by vitamin D which
serves as cofactor in Ca 2+ transport
H. Movement
1. segmentation
2. peristalsis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 119 Digestive System
I. Control of small intestine activity
1. Hormonal control
a. gastrin – secreted by stomach
1) stimulates contraction of intestinal smooth muscle
2) stimulates relaxation of ileocecal valve
b. vasoactive intestinal peptide (VIP)
1) secreted by duodenum
2) stimulates secretion of bicarbonate-rich intestinal
juice
c. somatostatin inhibits activity
2. Nervous system control
a. sympathetic impulses decrease activity
b. gastroileal reflex
1) response to gastric activity
2) long reflex involving brain and parasympathetic
innervation (increases activity)
V. Liver Fig. 24.1, p. 888; Fig. 24.23, p. 919
A. Gross anatomy
1. Largest gland/organ in body, approximately 1.4 kg
2. Upper right hypochondriac and epigastric regions
3. 4 primary lobes: right, left, caudate, quadrate
4. Covered by serosa except for uppermost region just under
diaphragm
B. Hepatic ducts Fig. 24.20, p. 915
1. Right hepatic duct
2. Left hepatic duct
3. Common hepatic duct
a. joins with cystic duct of gall bladder to form common
bile duct
common bile duct joins with pancreatic duct to form
hepatopancreatic ampulla
C. Ligaments Fig. 24.23, p. 919
1. Falciform ligament
a. formed from mesentary
E. Lathrop-Davis / E. Gorski / S. Kabr hel 120 Digestive System
b. separates right and left lobes
c. suspends liver from diaphragm and anterior abdominal
wall
2. Round ligament (ligamentum teres)
3. Ligamentum venosum
D. Blood supply Fig. 20.27, p. 771
1. Hepatic artery
2. Hepatic portal vein
3. Hepatic vein
E. Microscopic Anatomy Fig. 24.24, p. 921
1. Designed to filter and process nutrient-rich blood
2. Composed of lobules
a. portal triad
1) branch of hepatic artery
2) branch of hepatic portal vein
3) bile duct
b. sinusoids
1) hepatocytes (liver cells)
2) Kupffer cells (macrophages)
c. central vein drains lobule join to form hepatic veins
d. bile canaliculi
1) join to form bile ducts
2) flow counter to blood
F. Functions
1. Process blood-borne nutrients
2. Store glucose (as glycogen) and fat-soluble vitamins
3. Stores iron (Fe)
4. Detoxify poisons
5. Produce plasma proteins (See Topic 1 Blood)
6. Cleanse blood of debris, including bacteria and worn out
RBCs
7. Produce bile
a. consists of bile salts, bile pigments, cholesterol, neutral
fats, phospholipids, electrolytes in water
E. Lathrop-Davis / E. Gorski / S. Kabr hel 121 Digestive System
b. aid digestion of fat
1) emulsify fat globules into droplets
2) form micelles
c. bile salts conserved by enterohepatic circulation
d. main bile pigment is bilirubin
1) formed from breakdown of hemoglobin (See Topic 1
Blood)
2) metabolized by bacteria in large intestine )
e. control of bile production Fig. 24.25, p. 933
1) stimulated by bile salts returning via hepatic portal
blood
2) stimulated by secretin (hormone secreted by small
intestine in response to fats in chyme)
G. Liver disorders/diseases
1. Hepatitis – inflammation of liver, often caused by viral
infection
a. transmitted enterically (HVA) or through blood (HVB,
HVC, HVD)
b. blood-borne viruses are linked to chronic hepatitis and
cirrhosis
2. Cirrhosis – chronic disease characterized by growth of
scar tissue
3. Jaundice – yellowing of skin due to build up of bilirubin
from liver disease or excessive destruction of RBCs
VI. Gall Bladder
A. Gross structure
1. Lies in depression on ventral surface of liver
2. Thin-walled, muscular sac (holds about 50 ml)
3. Stores and concentrates bile
4. Releases bile via cystic duct
B. Histology
1. Mucosa
microvilli
2. Submucosa
3. Muscularis
4. Serosa
E. Lathrop-Davis / E. Gorski / S. Kabr hel 122 Digestive System
C. Control of bile release Fig. 24.25, p. 933
1. Bile produced by liver backs up into gall bladder when
hepatopancreatic sphincter is closed
2. Gall bladder releases bile into cystic duct when stimulated
by cholecystokinin (secreted by duodenum) and
parasympathetic impulses
3. Release inhibited by somatostatin produced by stomach
and duodenum
D. Gall bladder disorders
1. Gallstones (biliary calculi) – result from crystallization of
cholesterol due to excess of cholesterol or too little bile
salts
2. Obstructive jaundice – yellowish coloration of skin due to
build up of bile pigments caused by blockage of bile ducts
VII.Pancreas
A. Structural features Fig. 24.20, p. 915; Fig. 24.27, p. 924
1. Mostly retroperitoneal, head encircled by duodenum, tail
abuts spleen
2. Acinar cells (acini)
a. secrete pancreatic juice rich in enzymes, which are
stored in zymogen granules until release
b. pancreatic juice excreted through pancreatic duct
3. Islets of Langerhans
B. Composition of pancreatic juice
1. Watery, rich in bicarbonate (HCO3 -)
a. bicarbonate makes it alkaline and neutralizes acidity of
chyme
2. Digestive enzymes
a. proteases
1) released as zymogens
2) trypsin – released as trypsinogen (activated by
enterokinase enzyme in brush border cells)
3) carboxypeptidase & chymotrypsin – activated from
precursors (by procarboxypeptidase &
chymotrypsinogen, respectively) trypsin
b. pancreatic amylase
E. Lathrop-Davis / E. Gorski / S. Kabr hel 123 Digestive System
c. lipases
d. nucleases
e. nucleosidases
C. Control of pancreatic secretion Fig. 24.28, p. 925
1. Secretin
a. produced by small intestine in response to acid chyme
entering duodenum
b. stimulates secretion of bicarbonate-rich pancreatic
juice
2. Cholecystokinin
a. produced by small intestine in response to fatty,
protein-rich chyme entering duodenum
b. stimulates secretion of enzyme-rich pancreatic juice
3. Vagus (X) nerve – parasympathetic impulses stimulate
secretion during cephalic and gastric phases of digestion
D. Pancreas’ endocrine role (See A&P I Unit XI Endocrine
System)
1. Insulin
a. secreted when blood glucose increases
b. lowers blood sugar by:
1) stimulating uptake by body cells (except liver,
kidney and brain)
2) stimulating glycogen formation in liver and skeletal
msucle
3) inhibiting gluconeogenesis
4) stimulating glucose catabolism in most cells
2. Glucagon
a. secreted in response to low blood glucose
b. increases blood sugar by:
1) stimulating glycogenolysis
2) stimulating gluconeogenesis
3) stimulating release of glucose into blood by liver
4) inhibiting uptake
E. Lathrop-Davis / E. Gorski / S. Kabr hel 124 Digestive System
E. Disorders of the pancreas – Pancreatitis
1. may be caused by excessive fat in blood
2. activation of enzymes within pancreas (pancreas digests
itself)
VIII. Large Intestine
A. Location and structure Fig. 24.29, p. 928
1. Located primarily in abdominal cavity, distal end is in pelvic
cavity
2. Larger in diameter, but shorter (~1.5 m) than small
intestine
3. Modifications:
a. teniae coli
b. haustra (singular = haustrum)
c. epiploic appendages
4. Subdivisions
a. cecum
vermiform appendix
b. colon
1) ascending
2) transverse
3) descending
4) sigmoid
c. rectum
d. anal canal
1) internal anal sphincter
2) external anal sphincter
B. Microscopic anatomy Fig. 24.29, p. 928
1. Mucosa
a. crypts
b. goblet cells
2. Anal canal arranged as anal columns
a. composed of stratified squamous epithelium
b. anal sinuses
E. Lathrop-Davis / E. Gorski / S. Kabr hel 125 Digestive System
C. Histology Fig. 24.31, p. 930
1. Mucosa
a. simple columnar epithelium with lots of goblet cells
b. stratified squamous epithelium in anal canal
2. Submucosa has less lymphatic tissue
3. Muscularis – teniae coli
4. Serosa
D. Intestinal flora
1. resident bacteria dominated by Escherichia coli ( E. coli)
2. ferment some indigestible carbohydrates resulting in
mixture of irritating acids and gases
3. synthesize B vitamins and vit. K
E. Digestion
1. Chemical digestion - no additional breakdown of molecules
except by bacteria
2. Absorption
a. reabsorption of water and electrolytes
b. absorption of vitamins produced by bacteria
3. Movements in large intestine
a. formation of feces
b. haustral churning
1) slow process in which distention of haustrum
stimulates contraction which moves food into next
haustrum
2) mixes food residue and aids water reabsorption
c. mass peristalsis
1) long, slow movements along length of large intestine
force food toward rectum
2) stimulated by gastrocolic reflexes
d. defecation
1) parasympathetic reflex relaxation of smooth muscle
sphincter
2) voluntary relaxation of external sphincter (skeletal
muscle)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 126 Digestive System
F. Disorders of the large intestine
1. Appendicitis – inflammation of the appendix, usually caused by bacterial
infection
2. Diarrhea
a. watery stools due to shortened residence time
b. irritants, bacterial or viral disease
c. loss of water and electrolytes can lead to dehydration and electrolyte
imbalances
3. Constipation
a. hard stools due to increased time for water reabsorption
b. can also lead to electrolyte and pH imbalances
4. Hemorrhoids – inflammation of the superficial anal veins
5. Colitis – inflammation of the colon
6. Diverticulosis
a. formation of small herniations in mucosa of large intestine
b. common in elderly, especially those whose diets are low in bulk (fiber from
fruits and vegetables provides bulk)
7. Diverticulitis - inflammation of diverticula
8. Crohn’s disease – chronic inflammation; usually in ileum or large intestine
E. Lathrop-Davis / E. Gorski / S. Kabr hel 127 Digestive System
TOPIC 9
Nutrition, Metabolism & Thermoregulation
Ch. 25, pp. 949-997
Objectives
Nutrition
1. Define nutrient, major and minor nutrients, essential amino acid, essential fatty acid,
and calorie.
2. Distinguish between major and minor nutrients.
3. Classify proteins, lipids, carbohydrates, water, minerals, and vitamins as major or minor
nutrients.
4. List the six major food groups and relate them to the food pyramid.
5. Discuss the sources and uses of carbohydrates, proteins and lipids.
6. Distinguish between essential and nonessential amino acids.
7. Distinguish between nutritionally complete and incomplete proteins.
8. Explain what a vegetarian needs to do to gain all amino acids
9. Distinguish between essential and nonessential fatty acids.
10. List and give examples of the six functional types of proteins.
11. List the water-soluble and fat-soluble vitamins.
12. List the minerals important to good health.
13. Describe the important functions of calcium (Ca), iron (Fe), potassium (K), sodium (Na),
phosphorus (P), iodine (I)
Metabolism
1. Define metabolism, catabolism and anabolism.
2. Differentiate between substrate-level and oxidative phosphorylation.
3. Summarize the oxidation of glucose by describing the major steps (glycolysis, Kreb’s
cycle, electron transport chain) and their products.
4. Describe how the liver functions in metabolism.
5. Define glycogenesis, glycogenolysis, gluconeogenesis.
6. Define transamination and deamination and explain their roles in amino acid metabolism.
7. Relate the function of the liver to the functions and composition of blood.
8. Relate the function of the liver to blood pressure and capillary dynamics.
Thermoregulation
1. Define basal metabolic rate.
2. Describe the factors that contribute to body heat.
3. Describe the mechanisms of heat exchange.
4. Describe the role of the hypothalamus in regulating body temperature.
5. Describe what the body does to maintain body temperature in response to cold
environment and hot environments
E. Lathrop-Davis / E. Gorski / S. Kabr hel 128 Nutrition, Metabolism and Ther moregulation
Disorders
1. Describe the following disorders of metabolism or thermoregulation.
a. Hyperthermia
i. Heat stroke
ii. Heat exhaustion
iii. Fever
b. Hypothermia
2. Differentiate among heat exhaustion, heat stroke and fever.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 129 Nutrition, Metabolism and Ther moregulation
Topic 9: Nutrition, Metabolism & Thermoregulation
I. Definitions:
A. Calorie
B. Nutrient
1. Major nutrients
a. carbohydrates, proteins, lipids
b. water
1) ingested water
2) metabolic water
2. Minor nutrients
a. vitamins
b. minerals
C. Major food groups
1. Grains (bread, cereal, rice, pasta)
2. Fruits
3. Vegetables
4. Protein (meat, poultry, fish, beans, eggs, nuts)
5. Dairy (milk, yogurt, cheese)
6. Fats, oils, sweets
II. Carbohydrates
A. Dietary sources – mostly from plants (lactose comes from milk)
B. Uses in the body
1. energy source
a. glucose
b. fructose and galactose - converted to glucose
2. structure
3. cell recognition
E. Lathrop-Davis / E. Gorski / S. Kabr hel 130 Nutrition, Metabolism and Ther moregulation
C. Storage
1. medium-term storage - glycogen in liver, and skeletal and
cardiac muscle
2. long-term storage of excess - triglycerides (fat) in adipose
D. Cellulose
E. Hormonal control of blood glucose (see A&P I Unit XI
Endocrine System)
1. hypoglycemic hormones - insulin
2. hyperglycemic hormones
a. glucagon
b. glucocorticoids (cortisol)
c. epinephrine
d. growth hormones
III. Lipids
A. Dietary sources
1. Neutral fats (triglycerides)
a. saturated fats
b. unsaturated fats
1) monounsaturated fats
2) polyunsaturated fats
2. Cholesterol
B. Essential fatty acids
1. Linoleic acid
2. Linolenic acid
C. Uses in the body
1. Component of adipose
a. long-term energy storage
b. cushions organs
c. insulates
2. Component of plasma membranes (phospholipids;
cholesterol)
3. Regulatory molecules
E. Lathrop-Davis / E. Gorski / S. Kabr hel 131 Nutrition, Metabolism and Ther moregulation
IV. Proteins
A. Dietary sources Fig. 25.2, p. 952
1. “All-or-none rule”
2. Complete proteins
a. contain all essential amino acids
b. from animal products
3. Incomplete proteins
a. low amounts of or lacking certain amino acids
b. plant proteins
1) most are incomplete
2) need to be mixed to get all essential amino acids
(mix grains, like rice or corn, with legumes, like peas
or beans)
B. Essential amino acids
1. Cannot be made by the body (liver lacks the proper
enzymes)
2. Vegetarians can get all by combining grains (e.g., corn, rice)
with legumes (beans, peas)
C. Uses in the body
1. Structure
2. Catalysts
3. Transport & storage
a. intracellular transport
b. membrane channels and facilitated transport carriers
c. hemoglobin, myoglobin, ferretin, transferring,
hemosiderin (see Topic 1 Blood)
4. Contraction
5. Regulation
a. hormones (See A&P I Unit XI Endocrine System)
b. calmodulin (See A&P I Unit XI Endocrine System; A&P
I Unit XIII Muscular System)
6. Defense – immunoglobulins (See Topic 6 Resistance)
D. Miscellaneous
1. adequacy of caloric intake
2. nitrogen balance
E. Lathrop-Davis / E. Gorski / S. Kabr hel 132 Nutrition, Metabolism and Ther moregulation
a. intake (amino acids) = loss (urea)
b. transamination
c. deamination
E. Hormonal control (See A&P I Unit XI Endocrine System)
1. anabolic hormones – testosterone, growth hormone
2. catabolic hormones - glucocorticoids
V. Vitamins Table 25.2, p. 955-958
A. Two major groups
1. Water-soluble vitamins
a. Vit. C, B-complex vit.
b. absorption of Vit. B1 2 requires presence of intrinsic
factor
pernicious anemia
c. some made by gut bacteria
d. excess usually eliminated in urine
2. Fat-soluble vitamins
a. Vit. A, D, E and K
1) Vit. K produced by gut bacteria
2) Vit. D made by body (See A&P I Unit III
Integumentary System)
b. absorption aided by micelles in small intestine
c. excess Vit. A, D, and E stored in fat (megadoses may
cause problems)
B. Uses in body
1. Coenzymes
a. aid enzyme actions
b. riboflavin and niacin form part of electron carriers
(FAD and NAD+ , respectively) that carry electrons
during catabolism of glucose
2. Antioxidants (Vit. A, C and E)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 133 Nutrition, Metabolism and Ther moregulation
VI. Minerals Table 25.3, p. 958-961
A. Dietary sources – vegetables, legumes, milk, some meats
B. Intake requirements
1. Some minerals required in large amounts (calcium,
potassium, phosphorus, sulfur, sodium, chloride, magnesium)
C. Others required in small amounts (trace minerals, including
iron, zinc and iodine)
D. Uses in body
1. Structure (especially calcium and magnesium salts in bones
and teeth; phosphate – PO4 2-)
2. Enzyme cofactors (e.g., Mg2+)
3. Oxygen transport by hemoglobin and storage by myoglobin
(iron is central part of heme)
4. Ionic and osmotic balances (especially Na+ , K+ , Cl-)
5. Action potentials and impulses (Na+ , K+ , Ca2+ )
6. Muscle contraction (Na + , K+ , Ca2+ )
7. Thyroid hormones (I-)
8. Clotting (Ca 2+ ; See Topic 1 Blood)
9. Energy (phosphate – PO4 2-)
VII. Metabolism – Definitions
A. Metabolism
B. Anabolism
1. require energy (ATP) input
2. e.g., protein synthesis
C. Catabolism
1. cellular respiration releases energy, some of which is used
to make ATP
2. e.g., oxidation of glucose, fats, amino acids
D. Substrate-level phosphorylation Fig. 25.4, p. 964
=
1. transfer of PO4 from one molecule to ADP
2. glycolysis, Kreb’s cycle
3. phosphocreatine (skeletal muscle)
E. Oxidative phosphorylation
1. aerobic
2. mitochondria
E. Lathrop-Davis / E. Gorski / S. Kabr hel 134 Nutrition, Metabolism and Ther moregulation
VIII. ATP production Fig. 25.5, p. 965; Fig. 25.10, p. 972
A. Glycolysis Fig. 25.6, p. 966
1. Produces pyruvate
2. Net of 2 ATP per glucose by substrate-level
phosphorylation
3. Occurs in cytoplasm
4. Anaerobic
B. Kreb’s cycle Fig 25.7, p. 968
1. Net of 2 ATP per glucose (1 per pyruvate) by substrate-
level phosphorylation
2. Occurs in mitochondria
3. Aerobic
4. Requires intermediate step using acetyl-CoA
5. Produces CO2 and reduced energy carriers (FADH 2 and
NADH + H +)
C. Electron transport and oxidative phosphorylation Fig. 25.8, p. 969; Fig. 25.9, p. 971
1. 32 (in most cells) or 34 (in liver) ATP
2. Occurs in mitochondrion
3. Uses energy of electrons in FADH 2 and NADH(+H)
generated by glycolysis or Kreb’s cycle
a. creates H+ gradients
b. gradient provides energy for synthesis of ATP by ATP
synthase in inner mitochondrial membrane
4. Aerobic (O2 acts as final electron acceptor)
5. Produces “metabolic” water
D. Total ATP produced per glucose molecule broken down = 36 in
most cells, 38 in liver
IX. Role of the Liver in Metabolism
A. Fat metabolism
1. Packages fatty acids into forms that can be stored or
transported
2. Stores fat
3. Synthesizes cholesterol (from which it can synthesize bile
salts)
4. Forms lipoproteins for transport of fats, fatty acids and
cholesterol to and from other tissues
E. Lathrop-Davis / E. Gorski / S. Kabr hel 135 Nutrition, Metabolism and Ther moregulation
a. VLDLs – carry triglycerides from liver to peripheral
tissues (mostly adipose)
b. LDLs cholesterol-rich lipoproteins transporting
cholesterol from adipose to peripheral tissues for
incorporation into plasma membrane
c. HDLs
1) transport cholesterol from peripheral tissues to
liver for removal
2) pick up cholesterol from tissues and from arterial
walls
3) transport cholesterol to gonads and adrenal cortex
B. Protein metabolism
1. Synthesizes plasma proteins
2. Synthesizes nonessential amino acids by transamination
3. Converts ammonia formed from deamination of amino acids
into urea
C. Carbohydrate metabolism
1. Stores glycogen when glucose is abundant (stimulated by
insulin)
2. Releases glucose when blood glucose is low (stimulated by
glucagon) or during times of stress (epinephrine,
glucocorticoids)
a. gluconeogenesis
b. glycogenolysis
D. Miscellaneous
1. Stores vitamins (A, D, B1 2 )
2. Stores iron from worn-out red blood cells (See Topic 1
Blood)
3. Degrades hormones
4. Detoxifies toxic substances (e.g., drugs, alcohol)
X. Thermoregulation: Body Temperature and Regulation
A. Miscellaneous
1. Normal body temperature = 96-100 oF (35.6-37.8 oC)
a. varies with activity and time of day
b. represents a balance between heat production and heat
loss
E. Lathrop-Davis / E. Gorski / S. Kabr hel 136 Nutrition, Metabolism and Ther moregulation
2. Core temperature
a. temperature of organs within skull, thoracic and
abdominal cavities
b. more critical than shell temp.
3. Shell temperature = temperature of skin
4. Increased temperature increases chemical reaction rates
B. Heat exchange mechanisms
1. Radiation
2. Conduction
C. Heat lost mechanisms
1. Convection
2. Evaporation
D. Heat producing mechanisms
1. Basal metabolism (amount of energy needed to maintain
body at rest without activity from digestion)
a. most heat is generated by activity in the brain, liver,
endocrine organs, and heart
b. inactive skeletal muscle accounts for 20-30%
2. Muscular activity
a. uses more ATP
b. shivering
3. Thyroxine and epinephrine stimulate metabolic rates in
cells (See A&P I Unit XI Endocrine System)
E. Role of the hypothalamus
1. Thermoreceptors respond to changes in temperature
2. Thermoregulatory centers
a. heat-loss center
1) activated when core temperature rises above normal
2) promotes heat loss
b. heat-promoting center
1) activated when core temperature falls below normal
2) promotes production of heat
E. Lathrop-Davis / E. Gorski / S. Kabr hel 137 Nutrition, Metabolism and Ther moregulation
F. Keeping the body warm in response to cold environment
1. Fast-acting mechanisms
a. vasocontriction of cutaneous blood vessels keeps warm
blood closer to core
b. increased metabolic rate
1) non-shivering thermogenesis = increased metabolic
rate in response to norepinephrin secreted by
sympathetic nervous system
2) shivering (brain alternately stimulates small
contractions in antagonistic muscles)
c. behavioral modifications
2. Slow-acting mechanism: enhanced thyroxine release in
response to seasonal cooling (See A&P I Unit XI Endocrine
System)
G. Cooling the body when core becomes too hot
1. Vasodilation of cutaneous blood vessels
2. Enhanced sweating
3. Behavioral changes
XI. Imbalances of Thermoregulation
A. Hyperthermia
1. Heat exhaustion – elevated body temperature and mental
confusion or fainting due to dehydration
2. Heat stroke – loss of ability to regulate body heat due to
increased body temperature (a rather nasty form of
positive feedback)
3. Fever
a. controlled hyperthermia in response to infection
b. may also be caused by cancer, allergic reactions, CNS
injuries
c. increased temperature promotes function of white
blood cells
B. Hypothermia - core temperature may drop so low that CNS
function stops
E. Lathrop-Davis / E. Gorski / S. Kabr hel 138 Nutrition, Metabolism and Ther moregulation
E. Lathrop-Davis / E. Gorski / S. Kabr hel 139 Nutrition, Metabolism and Ther moregulation
TOPIC 10
Urinary System
Ch. 26, pp. 1004-1036
Objectives
Introduction
1. Describe the functions of the urinary system.
2. Describe the locations of the urinary system structures.
Kidney Anatomy
1. Describe the gross anatomy of the kidney and its coverings.
2. Describe the internal anatomy of the kidney.
3. Describe the innervation of the kidney.
4. Describe the blood supply of the kidney.
5. Describe the anatomy and function of a nephron.
Kidney Physiology
1. List the kidney functions that help maintain body homeostasis.
2. List and explain the processes involved in urine formation.
3. Identify the parts of the nephron responsible for filtration, reabsorption, and
secretion.
4. Describe the mechanisms of filtration, reabsorption, and secretion.
5. List and describe the forces that support and oppose filtration.
6. Compare the reabsorption processes occuring in the PCT, descending and ascending
limbs of the loop of Henle', and the DCT.
7. Describe the intrinsic and extrinsic controls of filtration.
8. Describe the control of reabsorption.
9. Define concentration and explain how it may be changed.
10. Explain the role of aldosterone, antidiuretic hormone, and atrial natriuretic peptide in
sodium and/or water balance.
11. Explain the role of parathyroid hormone (PTH) in calcium reabsorption.
12. Describe how the medullary osmotic gradient is established and maintained.
13. Explain how the kidney forms dilute urine and concentrated urine
14. Describe the normal physical and chemical properties of urine.
15. List abnormal urine components, and name the condition(s) when each is present in
detectable amounts.
16. Integrate the function of the liver in protein metabolism with urinary function.
17. Integrate the control of blood pressure and urine output (e.g., explain how the urinary
system regulates blood pressure and how blood pressure affects urine production).
18. Diagram the effects of dehydration on urinary output, blood pressure and electrolyte
balance including the body's hormonal and renal responses.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 140 Urinary System
19. Diagram the effects of overhydration on urinary output, blood pressure and electrolyte
balance including the body's hormonal and renal responses.
Ureters, Urinary Bladder, and Urethra
1. Describe the general structure and function of the ureters.
2. Describe the general structure and function of the urinary bladder.
3. Describe the general structure and function of the urethra.
4. Compare the course, length, and functions of the male urethra with those of the
female.
5. Trace the flow of filtrate, urine and blood through the appropriate structures and
blood vessels of the kidney and urinary system.
Micturition
1. Define micturition and describe the micturition reflex.
Disorders
1. Describe the following urinary system disorders.
a. Incontinence
b. Cystitis
c. Bladder infection
d. Renal calculi
e. Nephritis
f. Pyelonephritis
g. Anuria
h. Diabetes:
i. insipidus
ii. mellitus
iii. steroid diabetes (persistent hyperglycermia)
2. Compare and contrast the three types of diabetes.
See also A.D.A.M. Interactive Physiology Urinary System
* Anatomy Review
* Glomerular Filtration
* Early Filtrate Processing
* Late Filtrate Processing
E. Lathrop-Davis / E. Gorski / S. Kabr hel 141 Urinary System
Topic 10: Urinary System
I. Functions of the Urinary System
A. Main function: regulate the composition and volume of blood
by:
1. Maintaining water content
2. Maintaining ionic balance
3. Maintaining pH balance
4. Removal of metabolic wastes (especially nitrogenous
wastes)
B. Other functions:
1. Regulate blood pressure (See Topic 4 Blood Pressure)
2. Regulate red blood cell (erythrocyte) formation (See Topic
1 Blood)
3. Gluconeogenesis during prolonged fasting
II. Overview of Components Fig. 26.1, p. 1004; Fig. 26.2, p. 1005
A. Kidneys
1. Retroperitoneal in upper lumbar region
2. Perform functions of urinary system
B. Ureters
1. Extend from kidney into pelvic cavity
2. Transport urine from renal pelvis to urinary bladder
C. Urinary bladder
1. In pelvic cavity
2. Temporary storage of urine before micturition
D. Urethra
1. Extends from bladder to surface
2. Transports urine to outside
III. Gross Anatomy
A. Kidneys Fig. 26.3, p. 1006
1. Coverings
a. renal fascia
b. adipose capsule
c. renal capsule
E. Lathrop-Davis / E. Gorski / S. Kabr hel 142 Urinary System
2. Regions
a. cortex
b. medulla
c. renal sinus
B. Ureters
1. mucosa – transitional epithelium
2. muscularis – smooth muscle
3. adventitia – fibrous connective tissue
C. Urinary Bladder Fig. 26.18, p. 1031
1. Mucosa
a. designed to withstand stretching
b. transitional epithelium
2. Muscularis
a. smooth muscle
b. contracts to expel urine
D. Urethra
1. Lining varies from transitional to pseudostratified
columnar to stratified squamous epithelium
2. Internal sphincter of smooth muscle
3. External sphincter of skeletal muscle
* Details of structure will be covered in lab
IV. Internal Anatomy of the Kidney Fig. 26.3, p. 1006
A. Renal cortex
Renal columns
B. Renal Medulla
1. Medullary (renal) pyramids
2. Papilla
C. Renal pelvis
1. Major calyces (singular = calyx)
2. Minor calyces
E. Lathrop-Davis / E. Gorski / S. Kabr hel 143 Urinary System
V. Kidney Blood and Nerve Supply
A. Nerve supply Fig. 14.5, p. 519
1. Renal plexus – autonomic
a. sympathetic nerve fibers
b. control vasomotor tone of renal arterioles
B. Blood Supply Fig. 26.3, p. 1006; Fig. 20.22, p. 761; Fig. 20.27, p. 771
1. Renal artery & renal vein (branches covered in lab)
2. Capillary Beds (Microvasculature) Fig. 26.5, p. 1010
a. glomerulus Fig. 26.7, p. 1011
1) fed by afferent arteriole
i. arise from interlobular arteries
ii. larger than efferent arteriole
2) capillary bed itself
i. fenestrated capillaries
ii. surrounded by glomerular (Bowman’s) capsule of
nephron
iii. filtration membrane
3) drained by efferent capillary – which also gives rise
to peritubular capillaries and vasa recta
b. peritubular capillaries
1) arise from efferent capillary
2) follow renal tubules
3) low pressure
4) porous
c. vasa recta
1) arise from efferent capillary
2) follow loop of Henle’ of juxtamedullary nephrons
toward medulla
VI. Nephrons, the Functional Unit of the Kidney Fig. 26.4, p. 1008
A. Regions
1. Glomerular (Bowman’s) capsule
a. found in cortex
b. cup-shaped, blind sac
c. surrounds glomerulus
1) glomerular capsule + glomerulus = renal corpuscle
E. Lathrop-Davis / E. Gorski / S. Kabr hel 144 Urinary System
i. parietal layer
(a) outer wall of renal corpuscle
(b) simple squamous epithelium
ii. visceral layer
(a) inner layer in contact with glomerulus
(b) similar to simple squamous epithelium
(i) podocytes
(ii) filtration slits
2) capsular space
2. Proximal convoluted tubule (PCT) Fig. 26.4, p. 1008
a. found in cortex
b. designed for absorption and secretion
c. consists of:
1) simple cuboidal epithelium
2) microvilli (brush border)
3. Loop of Henle’ Fig. 26.5, p. 1010
a. important to concentrating urine
b. location
1) most found entirely in cortex
2) juxtamedullary nephrons extend into medulla
c. descending limb ~ thin segment
d. ascending limb ~ thick segment
4. Distal convoluted tubule (DCT) Fig. 26.4, p. 1008
a. found in cortex
b. designed for secretion and absorption
c. simple cuboidal epithelium
B. Types of Nephrons Fig. 26.5, p. 1010
1. Cortical nephrons – located entirely in cortex (or almost
entirely, loops may dip into upper medulla)
2. Juxtamedullary nephrons
a. renal corpuscle located in cortex close to border with
medulla
b. loops of Henle’ extend into medulla
c. especially important to forming concentrated urine
3. Juxtaglomerular Apparatus Fig. 26.7, p. 1011
E. Lathrop-Davis / E. Gorski / S. Kabr hel 145 Urinary System
a. juxtaglomerular (JG) cells – parts of afferent and
efferent arterioles
1) modified smooth muscle
2) respond to decreased blood pressure (BP)
3) secrete renin when BP drops
b. macula densa (MD) cells – part of distal convoluted
tubule
1) contains osmoreceptors
2) respond to changes in solute concentration of
filtrate in lumen of tubule
3) secrete local vasoconstrictor to control flow into
glomerulus
VII. Mechanisms of Urine Formation Fig. 26.9, p. 1013
A. Approx. 1-1.2 l of blood passes through kidney per minute
B. Approx. 99% of filtrate is reabsorbed
C. Glomerular Filtration Fig. 26.10, p. 1015
1. Occurs at the glomerulus
2. Approximately 120-125 ml filtered into glomerular space
per minute (about 180 L per day)
3. Filtrate resembles blood
a. normally lacks proteins and formed elements
b. ions and other solutes are in proportion to
concentration in blood
4. Net filtration pressure -- Review capillary dynamics (See
Topic 4 Blood Pressure)
a. NFP = forces into nephron – forces out of nephron
b. NFP = (HPg + OPc) – (OPg + HPc)
c. forces supporting filtration
1) glomerular hydrostatic pressure (HP g)
i. blood pressure within glomerulus
ii. normally approx. 55 mm Hg (varies somewhat
with systemic blood pressure)
iii. higher than most capillaries because efferent
arteriole is narrower than afferent arteriole
2) capsular osmotic pressure (OPc) - normally near 0
mm Hg because no proteins are filtered
E. Lathrop-Davis / E. Gorski / S. Kabr hel 146 Urinary System
d. forces opposing filtration
1) glomerular blood colloid osmotic pressure (OP g)
i. osmotic pressure created primarily by proteins
(albumins) in blood
ii. normally 28-30 mm Hg
2) capsular hydrostatic pressure (HP c)
i. pressure of fluids in glomerular space
ii. normally approx. 15 mm Hg
5. Glomerular Filtration Rate (GFR)
a. total amount of filtrate formed per minute (120-125
ml/min)
b. based on:
1) total surface area available for filtration*
2) permeability of filtration membrane *
3) net filtration pressure
i. varies somewhat with systemic blood pressure
ii. controlled
*normally, do not change; can be changed by disease
6. Regulation of Glomerular Filtration Fig. 26.11, p. 1016
a. intrinsic control (renal autoregulation)
1) kidney adjusts resistance to blood flow by
regulating diameter of afferent (and efferent)
arterioles
2) myogenic mechanism
i. attempt to maintain steady GFR
ii. responds to changes in pressure within renal
blood vessels
iii. increase in systemic BP stretches smooth
muscles, causes constriction of afferent
arterioles, decreases filtration pressure
iv. decrease in systemic BP causes dilation of
afferent arterioles, allows more blood to pass
through glomerulus, increases filtration pressure
to maintain removal of wastes
E. Lathrop-Davis / E. Gorski / S. Kabr hel 147 Urinary System
3) tubuloglomerular feedback mechanism
i. involves macula densa (MD) cells of distal
convoluted tubules (DCT)
ii. MD cells secrete a potent vasoconstrictor when:
(a) lots of filtrate is present and flow is high
(b) osmolarity (especially sodium and chloride
content) of filtrate is high because not as
much is being reabsorbed
iii. vasoconstrictor constricts afferent arterioles
(a) decreases flow
(b) allows increased reabsorption
iv. when flow or osmolarity is low, vasoconstrictor is
not secreted
afferent arteriole remains at normal size
allows maintenance of normal filtration
b. extrinsic control
1) autonomic nervous system
i. sympathetic stimulation results in
vasoconstriction of afferent arterioles (and to a
lesser extent, efferent arterioles) decreases
filtration less filtrate produced maintains
blood pressure by decreasing fluid volume lost
2) renin-angiotensin pathway (See Topic 4 Blood
Pressure)
i. renin secreted by juxtaglomerular cells when:
(a) BP in arterioles drops and they are no longer
stretched as much
(b) reduced filtrate flow stimulates macula
densa cells
(c) sympathetic nervous system or angiotentin
II stimulate JG cells
ii. renin hydrolyses angiotensinogen to angiotensin
I which is then converted to angiotensin II
(a) angiotensin II is a potent vasoconstrictor
(i) directly raises BP by increasing
peripheral resistance
(ii) causes greater constriction of efferent
than afferent arterioles
E. Lathrop-Davis / E. Gorski / S. Kabr hel 148 Urinary System
(b) angiotensin II also stimulates release of
aldosterone from adrenal cortex
(c) aldosterone acts on DCT to increase Na+
reabsorption increases obligatory water
reabsorption
D. Tubular Reabsorption Fig. 26.12, p. 1018
1. Absorption of solutes from filtrate and subsequent return
to blood
2. Reabsorbed substances:
a. most organic nutrients (e.g., glucose, amino acids)
b. most ions
1) Na+ , K+ and Ca2+ highly regulated
2) H + regulated to maintain pH balance
c. water – highly regulated
3. Substances that are generally not reabsorbed or
reabsorbed only in small amounts:
a. lack carriers, limited lipid solubility, large
b. nitrogenous wastes (urea, creatinine, uric acid)
1) 50% to 60% of urea is reabsorbed because it is
small
2) creatinine (derived from phosphorylated nitrogen
compound in skeletal muscle) – large, not lipid
soluble
3) uric acid is reabsorbed by PCT, but most is secreted
again later
4. Reabsorption pathways
a. transcellular
1) through tubule cells
2) materials must cross apical and basolateral
membranes
3) some materials require protein channels or carriers
for movement through membrane
b. paracellular
1) through tight junctions between cells
2) very limited
E. Lathrop-Davis / E. Gorski / S. Kabr hel 149 Urinary System
5. Mechanisms of reabsorption Fig. 26.12, p. 1018
a. passive transport – uses energy of concentration
gradient
1) diffusion
i. lipid-soluble substances
ii. urea substances
2) facilitated diffusion
i. requires membrane proteins
ii. some ions (e.g., Cl-, HCO3 -)
3) osmosis
i. obligatory water reabsorption
4) solvent drag
b. active transport – requires ATP at basolateral
membrane
1) primary active transport
i. sodium-potassium pump
ii. direct use of ATP
iii. creates Na+ gradients - Na+ moves into cells
because of gradient created by active transport
of Na+ into interstitial fluid at basolateral
membrane
iv. K+ returns to interstitial fluid through K+
channels in basolateral membrane due to
gradient created by pumping it into cell
2) secondary active transport
i. cotransportation of substance by same protein
that carries Na + from lumen of tubule into cells
of tubule wall
ii. substances: simple sugars (glucose, galactose,
fructose), amino acids
iii. transport maximum (Tm)
(a) maximum amount of substance that can be
reabsorbed per minute
(b) depends on number of carrier proteins in
membrane
E. Lathrop-Davis / E. Gorski / S. Kabr hel 150 Urinary System
6. Sites of reabsorption
a. proximal convoluted tubule (PCT)
1) 65% to 99% of solutes reabsorbed
2) about 65% of filtrate fluid reabsorbed (~35%
remains after PCT)
b. loop of Henle’ – water and NaCl
c. distal convoluted tubule (DCT) – reabsorption of water,
NaCl
d. collecting duct (CD) – NaCl, water, urea
7. Control of reabsorption reabsorption tied to hormonal
influences (See A&P I Unit XI Endocrine System)
a. aldosterone
1) from adrenal cortex
2) secreted in response to:
i. high extracellular K+
ii. low extracellular Na+
iii. low BP or blood volume (renin-angiotensin
pathway)
iv. ACTH
3) targets collecting ducts
4) obligatory water reabsorption
b. antidiuretic hormone (ADH)
1) produced by hypothalamus
2) secreted from posterior pituitary in response to
increased blood osmolarity
3) increases water permeability of DCTs and CDs
4) facultative water reabsorption
c. atrial natriuretic peptide (ANP)
1) inhibits reabsorption of Na +
2) secreted by atria of heart when BP rises
d. parathyroid hormone (PTH)
1) secreted by parathyroid glands when blood Ca2+
drops
2) increases Ca2+ reabsorption in DCT
e. diuretics
1) any solute that exceeds its transport maximum –
osmotic diuretic
E. Lathrop-Davis / E. Gorski / S. Kabr hel 151 Urinary System
2) chemicals that
i. inhibit ADH secretion (e.g., alcohol)
ii. inhibit sodium reabsorption (e.g., caffeine)
E. Tubular Secretion
1. Movement of solutes from blood (via interstitial fluid)
INTO filtrate
2. Solutes secreted include: H + , K+ , NH 4+ (ammonium ions),
organic acids, organic bases, urea, uric acid, certain drugs
(especially those similar to normal organic acids and bases)
3. Important to:
a. disposal of solutes not normally filtered (e.g., penicillin,
phenobarbitol)
b. eliminating undesirable solutes (e.g., urea, uric acid)
c. ridding body of excess K+
d. maintaining blood pH
VIII. Conserving Water While Removing Wastes Fig. 26.14, p. 1025
A. Purpose: concentrate undesirable substances while retaining
desirable NaCl and water
B. Concentration
1. Amount of solute in a given volume of solvent or solution
2. Changed by:
a. Changing amount of solute
1) adding solute increases concentration
2) removing solute decreases concentration
b. Changing amount of solvent (water)
1) adding solvent decreases concentration
2) removing solvent increases concentration
C. Mechanism – countercurrent multiplier in loop of Henle’ and
vasa recta
1. Direction of flow in ascending limb of loop is opposite flow
in descending limb
2. Filtrate entering loop is approximately isotonic with plasma
a. BUT, urea is concentrated somewhat relative to plasma
because water, NaCl and nutrients have been removed
E. Lathrop-Davis / E. Gorski / S. Kabr hel 152 Urinary System
3. Osmotic gradient exists between cortex and medulla
a. osmolality in cortex ~ 300 milliosmols (mosm)
b. osmolality in inner (deep) medulla ~ 1200 mosm
4. Descending limb of loop is relatively impermeable to
solutes, but freely permeable to water
5. Ascending limb is impermeable to water but NaCl is actively
reabsorbed from filtrate
6. Vasa recta removes excess water and solute
7. Lower portion of collecting ducts is permeable to urea,
which adds to high medullary osmolality
D. How it works
1. NaCl actively reabsorbed from filtrate in ascending limb
NaCl enters interstitial fluid (IF)
2. Entrance of NaCl into IF increases osmolality of IF
a. exerts osmotic pressure draws water out of loop,
b. BUT…ascending limb is impermeable to water
(descending limb is permeable)
3. Water flows out of descending limb into IF (i.e., water
leaves filtrate)
a. loss of water from filtrate increases concentration of
remaining solutes in filtrate
b. water is removed from IF around descending limb by
vasa recta solute concentration in IF stays high
4. Active transport of NaCl out of ascending limb lowers
osmolality of remaining filtrate
5. Remaining solutes more concentrated than at start due to
removal of water (and NaCl)
6. Role of vasa recta – countercurrent exchange (same
osmolality leaving as entering medulla)
a. run parallel to loop of Henle’ of juxtamedullary
nephrons and so descend into medulla
b. freely permeable to both water and NaCl preserves
osmotic gradient
1) water leaves as vasa recta descends into medulla,
reenters as vasa recta ascends back into cortex
2) salt enters as vasa recta descends into medulla,
leaves as vasa recta ascends back into cortex
E. Lathrop-Davis / E. Gorski / S. Kabr hel 153 Urinary System
E. Formation of Dilute Urine
1. Due to excess fluid intake, or decreased ADH or
aldosterone secretion
2. Normally, collecting ducts (CDs) not very permeable to
water, therefore, lots of water leaves with filtrate
dilute urine
3. Reabsorption of solutes from DCT and CDs further dilutes
urine
F. Formation of Highly Concentrated Urine (Water Conservation) Fig. 26.15, p. 1026
1. Due to dehydration or increased ADH or aldosterone
secretion
2. Urine concentrated by reabsorption of water
3. Water reabsorption increased when water permeability of
CDs increases
a. water permeability increases when ADH is present
b. ADH secreted by posterior pituitary in response to
stimulation of hypothalamus
c. hypothalamus stimulated by
1) increased plasma electrolytes (especially NaCl) or
2) aldosterone
IX. Characteristics and Composition of Urine (See Lab)
A. Normal constituents
1. Substances that are only partially reabsorbed (e.g., NaCl,
water, urea)
2. Substances that are normally secreted (e.g., K+ , H + , organic
acids, organic bases, certain drugs)
B. Abnormal constituents
1. Blood cells
2. Organic nutrients (e.g., simple sugars, amino acids)
3. Hemoglobin
4. Bile pigments
5. Proteins
E. Lathrop-Davis / E. Gorski / S. Kabr hel 154 Urinary System
X. Micturition (Urination) Fig. 26.20, p. 1033
A. Distension of urinary bladder stimulates stretch receptors visceral reflex arc
1. Sensory impulses sacral spinal cord segments parasympathetic impulses to
smooth muscle of bladder and internal urethral sphincter (smooth muscle)
bladder contracts, sphincter relaxes
2. Sensory impulses to brain allow conscious recognition of need to urinate
conscious control of external urethral sphincter of skeletal muscle
3. Reflexive bladder contractions subside after about 1 minute if chose not to
void; start again when ~ 200-300 ml more of fluid has accumulated
XI. Disorders
A. Incontinence
B. Bladder infection
C. Cystitis
D. Renal calculi
E. Nephritis
F. Pyelonephritis
G. Anuria
H. Diabetes
1. insipidus
2. mellitus
3. steroid diabetes
E. Lathrop-Davis / E. Gorski / S. Kabr hel 155 Urinary System
TOPIC 11
Fluid, Electrolyte & Acid-Base Balance
Ch. 27, pp. 1041-1063
Objectives
Body Fluids
1. Describe the body’s fluid compartments.
2. Differentiate between electrolytes and nonelectrolytes.
3. List the important electrolytes and nonelectrolytes.
4. Discuss the difference between the intracellular fluid and extracellular fluid in terms
of amounts of selected electrolytes
Water Balance
1. List the ways the body gains or loses water.
2. Diagram the feedback mechanisms that regulate water intake and hormonal controls of
water output in urine.
3. Explain the importance and routes of obligatory water losses.
Electrolyte Balance
1. Indicate the routes of entry and loss of selected electrolytes.
2. Describe the importance of ionic sodium in fluid and electrolyte balance of the body.
3. Explain the significance of electrolyte control to normal neural and muscular function.
4. Explain the importance of calcium, magnesium and chloride ions.
5. Briefly describe the regulation of sodium, calcium, potassium, magnesium, and anion
concentrations in the body.
6. Integrate the control of sodium and potassium balance with blood pressure and fluid
balance through the hormones ADH, ANP and aldosterone.
Acid-Base Balance
1. Define pH, acid and base.
2. Explain what strength, concentration and buffer mean.
3. List important sources of acids in the body.
4. Name the three major chemical buffer systems of the body and describe how each
operates to resist pH changes.
5. Describe how the respiratory system is involved in acid-base balance.
6. Describe how the kidneys regulate H + and HCO3 - concentrations in the blood.
7. Integrate the control of pH through the urinary and respiratory systems.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 156 Fluid, Electrolyte & Acid-Base Balance
Disorders
1. Describe the following disorders of water balance.
a. Dehydration
b. Hypotonic hydration (overhydration)
c. Edema
2. Define and describe the effects of the following electrolyte disorders:
a. Hyponatremia
b. Hypernatremia
c. Hypokalemia
d. Hyperkalemia
e. Hypocalcemia
f. Hypercalcemia
3. Define the following acid-base disorders
a. Acidosis
i. Metabolic acidosis
ii. Respiratory acidosis
b. Alkalosis
i. Metabolic alkalosis
ii. Respiratory alkalosis
4. Distinguish between acidosis and acidemia.
5. Describe the effects of acidemia.
6. Distinguish between alkalosis and alkalemia.
7. Describe the effects of alkalemia.
See also A.D.A.M. Interactive Physiology – Fluid, Electrolyte and Acid/Base Balance
* Introduction to Body Fluids
* Water Homeostasis
* Electrolyte Homeostasis
* Acid/Base Homeostatis
E. Lathrop-Davis / E. Gorski / S. Kabr hel 157 Fluid, Electrolyte & Acid-Base Balance
Topic 11: Fluid, Electrolyte and Acid-Base Balance
I. Fluid Compartments of the Body (See A&P I Unit I Introduction) Fig. 27.1, p. 1041
A. Intracellular Fluid (ICF)
B. Extracellular Fluid (ECF)
1. Plasma
2. Interstitial Fluid
II. Composition of Body Fluids
A. Water = universal solvent
B. Solutes
1. Nonelectrolytes
a. no electrical charge
b. polar (hydrophilic) compounds: carbohydrates, some
proteins
c. nonpolar (hydrophobic) compounds: lipids, other non-
lipid hydrophobic compounds (e.g., O 2 , CO2 )
2. Electrolytes
a. particles that ionize in water to form anions (negatively
charged) and cations (positively charged)
b. types of electrolytes
1) inorganic salts (e.g., NaCl, NaHCO3 , MgCl2 , KCl,
CaCO3) – do not form H+ or OH - when they
dissociate
i. e.g., NaHCO3 Na+ + HCO3-
ii. e.g., CaCO3 Ca2+ + CO3 =
2) acids
i. dissociate to form H + and an anion
ii. lower pH
iii. types
(a) inorganic acids
(i) e.g., HCl
(ii) HCl H+ + Cl-
(b) organic acids
(i) e.g., H 2 CO3 , amino acids
(ii) H 2 CO3 H+ + HCO3 -
E. Lathrop-Davis / E. Gorski / S. Kabr hel 158 Fluid, Electrolyte & Acid-Base Balance
3) Bases
i. dissociate to form OH - (e.g., NaOH) or accept H+
(NH 3)
ii. raise pH
iii. types
(a) inorganic bases
(i) e.g., NaOH: NaOH Na+ + OH -
(ii) e.g., NH 3 : NH 3 + H+ NH 4 +
(iii) e.g., NaHCO3
(b) organic bases -- e.g., nitrogen bases of DNA
and RNA
c. important electrolytes Fig. 27.2, p. 1043
+ - -
1) ECF: Na , Cl , HCO 3
2) ICF: K+ , HPO42-, Mg2+ , protein
III. Water Balance
A. Sources:
1. Ingested water
2. Metabolic water
B. Losses:
1. Urine (60%)*
2. Sweat
3. Lungs
4. Feces
5. Skin
C. Regulating intake – thirst response Fig. 27.5, p. 1045
1. Intake controlled by hypothalamus
2. Thirst stimulated by:
a. dry mouth (sensation carried to hypothalamus)
b. increased osmolality of ECF in hypothalamus
3. Results in urge to drink liquids
E. Lathrop-Davis / E. Gorski / S. Kabr hel 159 Fluid, Electrolyte & Acid-Base Balance
D. Regulating output
1. Obligatory water loss
a. loss through lungs (See Topic 7 Respiratory System)
b. loss through feces (See Topic 8 Digestive System)
c. loss across skin (See A&P I Unit III Integumentary
System)
2. Controlled water loss
a. sweat – controlled for body temperature regulation, not
fluid balance (See A&P I Unit III Integumentary
System)
b. urine – point of fluid loss control (See Topic 10)
1) ADH (See A&P I Unit XI Endocrine System; Topic 4
Blood Pressure; Topic 10 Urinary System)
i. protein hormone secreted by posterior pituitary
in response to impulses from hypothalamus
ii. released in response to
(a) increased osmolality of ECF (which increases
osmolality of IF in hypothalamic cells), and
(b) presence of aldosterone in plasma
iii. results in:
(a) increase water permeability of collecting
ducts
(b) water follows osmotic gradient back into
plasma facultative water reabsorption
2) aldosterone (See A&P I Unit XI Endocrine System;
Topic 4 Blood Pressure; Topic 10 Urinary System)
i. steroid hormone secreted by zona glomerulosa
of adrenal cortex
ii. increases Na+ reabsorption in CDs and DCTs
iii. reabsorption of Na+ adds to osmotic gradient in
IF water follows by osmosis obligatory
water reabsorption
3) diuretics
i. enhance urinary output (decrease reabsorption)
ii. alcohol – inhibits ADH secretion
iii. caffeine and most diuretic drugs – inhibit Na +
reabsorption
E. Lathrop-Davis / E. Gorski / S. Kabr hel 160 Fluid, Electrolyte & Acid-Base Balance
IV. Disorders of Fluid Balance (See Topic 4 Blood Pressure)
A. Dehydration
B. Hypotonic hydration Fig. 27.6, p. 1046
C. Edema
V. Electrolyte Balance
A. Electrolytes = charged particles
1. dissociate to form cations (+ charge) and anions (- charge)
2. include salts, acids, bases
B. Salts:
1. ionic compounds that form cations and anions other than H +
and OH - (hydroxide)
2. sources: foods, fluids (e.g., sodas), small amounts from
metabolism
3. losses:
a. perspiration in hot environment
b. feces
c. abnormal GI function leads to electrolyte imbalances
1) diarrhea
2) vomiting
d. urine*
C. Important salt-related electrolytes (See A&P I
Electrophysiology; Unit XIII Muscular System; Topic 2 Heart)
1. Na+
a. main extacellular cation, accounts for 90-95% of all
solutes in ECF
b. most important electrolyte in creating significant
osmotic pressure
c. important to neuron and muscle function
2. K+
a. important to neuron and muscle function due to its
influence on membrane potential (repolarization,
hyperpolarization)
b. also influences acid-base balance (to be discussed
shortly)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 161 Fluid, Electrolyte & Acid-Base Balance
3. Ca2+
a. important to neural and muscular function
1) maintaining correct Na + permeability of neuronal
membranes
2) exocytosis of neurotransmitter
3) muscle contraction
4) action potential in autorhythmic cardiac cells
b. other important functions:
1) clotting (= clotting factor IV)
2) important constituent of bone (calcium salts)
2+
4. Mg
a. important to enzymes involved in protein and
carbohydrate metabolism
b. important component of bone
5. Cl- (chloride): main anion; follows Na+
D. Control of Selected Electrolytes(See A&P I Unit XI Endocrine
System; Topic 4 Blood Pressure; Topic 10 Urinary System) Table 27.1, p. 1048
1. Sodium (Na+):
a. aldosterone Fig. 27.8, p. 1050
1) steroid hormone secreted by zona glomerulosa of
adrenal cortex
2) secreted in response to low Na + and angiotensin II
(renin-angiotensin pathway); also in response to high
K+
3) increases active reabsorption of Na+ from DCT and
CD (without aldosterone, little Na+ is reabsorbed
from DCT or CD)
b. antidiuretic hormone (ADH ) Fig. 27.7, p. 1049
1) produced by hypothalamus, secreted by posterior
pituitary
2) released in response to increased Na + increases
water reabsorption to decrease plasma osmolality
c. atrial natriuretic peptide (ANP; aka. atrial natriuretic
factor) Fig. 27.10, p. 1052
1) released in response to elevated BP
2) blocks reabsorption of Na +
3) blocks ADH and aldosterone secretion
E. Lathrop-Davis / E. Gorski / S. Kabr hel 162 Fluid, Electrolyte & Acid-Base Balance
d. estrogens
1) steroids produced by ovaries and zona reticularis of
adrenal cortex
2) enhance Na+ reabsorption
e. glucocorticoids
1) steroids produced by zona fasciculata of adrenal
cortex
2) enhance Na+ reabsorption
f. disorders
1) hyponatremia – decreased blood Na +
i. neurological dysfunction (brain swelling; mental
confusion, irritability, convulsions, progresses to
coma; muscular twitching)
ii. systemic edema (less osmotic pressure in
plasma)
2) hypernatremia – increased Na+
i. thirst
ii. CNS dehydration leading to confusion, lethargy,
progressing to coma
iii. increased neuromuscular irritability leading to
twitching and convulsions
2. Potassium (K+ )
a. regulated at CDs in cortex of kidney – K+ secretion tied
to Na+ reabsorption
b. most important factor in regulation = K+ concentration
in plasma
1) increased K+ directly stimulates cells of CDs
2) excess of K+ causes K+ to move into CD cells
secretion into filtrate
c. aldosterone – stimulates active secretion of K+
d. disorders
1) hypokalemia = decreased blood K+
i. cardiac arrhythmias
ii. muscular weakness
iii. alkalosis (due to action of kidney)
iv. hypoventilation (to compensate for alkalosis)
v. mental confusion
E. Lathrop-Davis / E. Gorski / S. Kabr hel 163 Fluid, Electrolyte & Acid-Base Balance
2) hyperkalemia= increased blood K+
i. nausea, vomiting, diarrhea
ii. bradycardia, cardiac arrhythmias, depression
and arrest
iii. skeletal muscle weakness and flaccid paralysis
3. Calcium (Ca 2+ )
a. parathyroid hormone (PTH)
1) secreted by parathyroid glands in response to
decreased plasma Ca 2+
i. acts on gut to increase Ca 2+ in plasma
ii. stimulates osteoclasts, inhibits osteoblasts
iii. in kidney, acts on DCT to increase active
reabsorption of Ca2+ (also inhibits PO4 2-
reabsorption to maintain balance between Ca2+
and PO4 2-)
b. calcitonin
1) secreted by thyroid in response to increased plasma
Ca2+
2) thought to only be really important during youth
when bones are being remodeled
3) stimulates ostoblasts in bones to deposit matrix
thus decreasing plasma Ca2+
c. disorders
1) hypocalcemia – decreased blood calcium
i. tingling in fingers, tremors, convulsions, tetany
ii. depressed cardiac function
iii. bleeder’s disease
2) hypercalcemia – increased blood calcium
i. bone wasting
ii. kidney stones
iii. nausea, vomiting
iv. cardiac arrhythmias and arrest
v. depressed respiration
vi. coma
4. Magnesium - reabsorption inhibited by PTH
E. Lathrop-Davis / E. Gorski / S. Kabr hel 164 Fluid, Electrolyte & Acid-Base Balance
5. Anions
a. Cl- is major anion - allows Na+ actively or passively in
PCT, DCT and CD
b. most others passively reabsorbed
1) involves membrane proteins for transport
2) transport maxima
3) any concentration in excess of transport maximum
is excreted in urine
VI. Acid-Base Balance
A. pH - measure of H + concentration in a liquid
1. pH of distilled water (i.e., neutral) = 7.0
2. Normal pH values
a. arterial blood = pH 7.4
b. venous blood and interstitial fluid = pH 7.35
c. intracellular fluid (ICF) = pH 7.0
3. protein function depends on H + concentration
B. Acids
1. Addition of H+ lowers pH
2. Metabolic sources of acids: (See Topic 9 Metabolism)
a. anaerobic respiration
b. protein catabolism
c. fat metabolism
C. Bases removal of H + or addition of OH - raises pH
D. Strength of acids/bases Fig. 27.11, p. 1046
1. Refers to ability to ionize
2. Strong acids/bases
a. dissociate readily and completely
b. are usually inorganic (e.g., HCl, KOH, NaOH, NH 3)
c. lead to large changes in pH when added to unbuffered
solutions
3. Weak acids/bases
a. do not completely ionize (i.e., some of the molecular
form remains)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 165 Fluid, Electrolyte & Acid-Base Balance
b. are usually organic (e.g., H 2 CO3 , NaHCO3 , amino acids,
fatty acids)
c. only change pH slightly when added to unbuffered
solutions
E. Regulation of Acid-Base Balance
1. Chemical buffer systems
a. act quickly
b. involve exchange of strong acid-base for weak one
c. three major chemical buffer systems
1) bicarbonate buffer system
i. only chemical buffer present in ECF
ii. carbonic acid (H 2 CO3) levels maintained by
breathing
iii. bicarbonate (NaHCO3) levels maintained by
kidney
2) phosphate buffer system - very important in ICF
and urine
3) protein buffer system
i. very important in ICF
ii. based on amino acid side chains
iii. reduced hemoglobin - takes on H + (increases pH)
2. Respiratory System
a. respiratory compensation – changes in ventilation to
compensate for metabolic changes to acid-base balance
1) decreased pH stimulates medulla to increase
ventilation increases loss of CO2
2) increased pH decreases stimulation of medulla
decreased ventilation decreases loss of CO2
3. Renal compensation of acid-base balance – makes up for
changes due to problems with respiration
a. kidney excretes or conserves HCO3 -, depending on
needs of body
1) excretes HCO3 - if pH increases
2) conserves HCO3 - if pH decreases
E. Lathrop-Davis / E. Gorski / S. Kabr hel 166 Fluid, Electrolyte & Acid-Base Balance
b. kidney excretes H +
1) excretes H + if pH decreases
2) conserves H + if pH increases
3) only kidney rids body of metabolic acids other than
H 2 CO3
4) H + competes with K+ for removal by kidney
(hyperkalemia can lead to decreased pH)
VII.Disorders of Acid-Base Balance
A. Changes in pH
1. Result from respiratory or metabolic causes
2. Increased pH = alkalosis; decreased pH = acidosis
Cause Increased pH Decreased pH
Respiratory disorder Respiratory alkalosis Respiratory acidosis
Metabolic disorder Metabolic alkalosis Metabolic acidosis
B. Alkalosis – any condition that may lead to alkalemia (pH of
arterial blood > 7.45)
1. respiratory alkalosis - increased ventilation
(hyperventilation) increased loss of CO2 less carbonic
acid
2. metabolic alkalosis
a. loss of H + through vomiting
b. constipation (retention of HCO3 -)
c. K+ depletion (competes with H+ for removal at kidney)
d. excess aldosterone secretion
C. Effects of Alkalemia
1. increased cardiac irritability and arrhythmias
2. compensatory hypoventilation (if cause is metabolic
alkalosis)
3. vascular changes (e.g., vasodilation, spasm of coronary
arteries, decreased cerebral blood flow)
4. seizures
5. increased blood lactate
6. hypokalemia and hypocalcemia
E. Lathrop-Davis / E. Gorski / S. Kabr hel 167 Fluid, Electrolyte & Acid-Base Balance
D. Acidosis (physiological acidosis) – any condition that may lead
to physiological acidemia (pH of arterial blood < 7.35 [which is
pH of venous blood and above neutral])
1. respiratory acidosis - build up of CO2 more carbonic acid
a. hypoventilation
b. impairment of lung function
2. metabolic acidosis
a. loss of HCO3 - in diarrhea (decreased reabsorption time)
b. renal disease (failure of kidney to excrete sufficient
H +)
c. excess alcohol intake (ethanol --> acetic acid)
d. high K+ in ECF (competes with H + for excretion)
e. lactoacidosis - build-up of lactic acid due to heavy
exercise or prolonged hypoxia (See A&P I Unit XIII
Muscular System)
f. ketoacidosis – generation of ketone bodies due to
improper glucose metabolism (starvation or diabetes
mellitus; See A&P I Unit XI Endocrine System)
E. Effects of Acidemia
1. increased pulmonary resistance leading to pulmonary edema
2. decreased cardiac function (e.g, bradycardia during severe
acidemia, ventricular fibrillation)
3. vascular changes (e.g, venoconstriction, arterial dilation
4. hyperkalemia
5. insulin resistance
6. coma
F. Respiratory compensation
1. for metabolic disorders
2. metabolic alkalosis – results in hypoventilation
3. metabolic acidosis – results in hyperventilation
G. Renal compensation
1. for respiratory acid/base disorders
2. respiratory alkalosis – excretion of HCO3 - +/or retention of
H+
E. Lathrop-Davis / E. Gorski / S. Kabr hel 168 Fluid, Electrolyte & Acid-Base Balance
3. respiratory acidosis
a. excretion of H+ +/or retention of HCO3 -
b. excretion of H+ may result in hyperkalemia (H+ and K+
complete for secretion)
E. Lathrop-Davis / E. Gorski / S. Kabr hel 169 Fluid, Electrolyte & Acid-Base Balance
TOPIC 12
Reproductive System
Ch. 28, pp. 1071-1107
Objectives
Anatomy of the Male Reproductive System
1. Describe the structure and function of the testes, and explain the importance of their
location in the scrotum.
2. Describe the location, structure, and function of the accessory organs of the male
reproductive system.
3. Describe the structure of the penis, and note its role in the reproductive system.
4. Discuss the sources and functions of semen.
5. Trace the flow of sperm from their site of origin to the point at which they would may
encounter an ovulated oocyte. Indicate where the products of the male accessory gland
enter the system.
Physiology of the Male Reproductive System
1. Define meiosis. Compare and contrast it to mitosis.
2. Diagram the process of spermatogenesis.
3. Discuss the hormonal regulation of testicular function and the physiological effects of
testosterone on male reproductive anatomy.
4. Explain the significance of the blood-testis barrier
Anatomy of the Female Reproductive System
1. Describe the location, structure, and function each of the organs of the female
reproductive duct system.
2. Describe the structure and function of the mammary glands.
Physiology of the Female Reproductive System
1. Diagram the process of oogenesis.
2. Describe the phases of the ovarian cycle, and relate them to the events of oogenesis.
3. Diagram the regulation of the ovarian and menstrual cycles.
4. Discuss the physiological effects of estrogens and progesterone.
5. Discuss the causes and consequences of menopause
6. Compare and contrast gamete production in males and females.
7. Compare the "goals" of the male and female reproductive systems.
8. Compare and contrast the hormonal regulation of testosterone and estrogens.
Developmental Milestones
1. List the important developmental milestones.
E. Lathrop-Davis / E. Gorski / S. Kabr hel 170 Reproductive System
Disorders
Describe the following disorders of the reproductive system.
1. Sexually transmitted diseases (STDs)
a. Gonorrhea
b. Syphilis
c. Chlamydia
d. Genital warts
e. Genital herpes
2. Ectopic pregnancy
3. Hypertrophy of prostate
4. Breast cancer
female cycle: animation - http://www.lmu.livjm.ac.uk/cytofocus/d3.html
E. Lathrop-Davis / E. Gorski / S. Kabr hel 171 Reproductive System
Topic 9: Reproductive System
I. Testes, Male Duct System and Penis Fig. 28.1, p. 1071
A. Testes Fig. 28.2, p. 1072
1. Located in scrotum - for temperature regulation (keeps
them at about 33 oC [91 oF])
2. Structure
a. seminiferous tubules
1) produce sperm
2) sustentacular (Sertoli) cells support
spermatogenesis
b. interstitial cells (cells of Leydig) produce testosterone
c. Rete testis
1) network of tubules on posterior side
2) lead to epididymus
d. coverings
1) tunica albuginea
2) tunica vaginalis
B. Ducts
1. Epididymus – site of sperm maturation
2. Ductus (vas) deferens – carries sperm away from testis to
ejaculatory duct
3. Ejaculatory duct –from where ducts from seminal vescicles
join ductus deferens to urethra
C. Urethra
1. Prostatic urethra – runs through prostate gland
2. Membranous urethra – runs from prostate to penis
3. Penile urethra – runs through penis
D. Penis – designed to deliver sperm into vagina of female
E. Male Accessory Glands and Semen
1. Seminal Vesicles
a. produce about 60% of all semen
b. alkaline fluid – neutralizes acidity of vagina
c. fructose* – nourishes sperm
E. Lathrop-Davis / E. Gorski / S. Kabr hel 172 Reproductive System
2. Prostate Gland
a. encircles urethra below bladder;
b. produces about 30% of semen
c. plays a role in activating sperm
d. citrate – nourishes sperm
3. Bulbourethral Glands
a. near base of penis
b. produce mucus that neutralizes acidity of traces of
urine in urethra
II. Spermatogenesis
A. Sperm (and ova) produced by meiotic cell division (meiosis +
karyokinesis)
B. Meiosis vs mitosis Fig. 28.6, p. 1078
C. Spermatogenesis Fig. 28.8, p. 1081
1. Spermatogonia divide by mitosis to produce
a. type A daughter cells that produce more spermatogonia
b. type B daughter cells that give rise to spermatocytes
2. Spermatocytes divide by meiosis to produce spermatids
a. primary spermatocyte is diploid, goes through meiosis I
to form 2 haploid secondary spermatocyte
b. 2 secondary spermatocytes undergo meiosis II to form
4 spermatids
c. spermatids undergo spermiogenesis to form viable
sperm
D. Spermiogenesis Fig. 28.9, p. 1082
1. spermatids develop into functional sperm
2. development of:
a. flagellum
b. acrosome
c. midpiece
E. Lathrop-Davis / E. Gorski / S. Kabr hel 173 Reproductive System
E. Sustentacular cells
1. Surround and support developing spermatocytes and
spermatids
2. Extend from basal lamina to lumen of tubule
3. Form blood-testis barrier
a. separate developing spermatocytes/spermatids from
blood
b. important because sperm are first produced after
immune system has developed sense of “self” sperm
would be recognized as foreign if contact blood
III. Hormonal Regulation of Male Function
Hypothalamus secretes GnRH (Gonadotropin-releasing hormone)
Stimulates anterior pituitary to release
follicle stimulating hormone (FSH) lutenizing hormone (LH)
indirectly stimulates testosterone secretion stimulates testosterone secretion
stimulates inhibin release (inhibits FSH and LH release)
stimulates spermatogenesis
testosterone:
stimulates spermatogenesis
stimulates development and maintenance of
male secondary sex characteristics
development of male sex drive
protein synthesis in bone and muscle
IV. Ovaries and Female Duct System
A. Ovaries
1. Located lateral to uterus
2. Ligaments anchor ovary to other structures
a. ovarian ligament – anchor ovary to uterus
b. broad ligament
1) suspensory ligament – anchors ovary to lateral pelvic
wall
2) mesovarium – hold ovary between ovarian and
suspensory ligaments
E. Lathrop-Davis / E. Gorski / S. Kabr hel 174 Reproductive System
3. Contain oocytes surrounded by follicles
4. Release secondary oocytes into pelvic cavity
B. Uterine (fallopian) tubes
1. Carry oocyte toward uterus
2. Fimbriae immediately pick up secondary oocyte released
from ovary and transfer it into UT
3. Smooth muscle and cilia of simple columnar epithelium help
move oocyte toward uterus
C. Uterus
1. normal site of implantation of fertilized ovum and
development of fetus
2. Layers
a. endometrium
1) inner-most layer
2) forms maternal part of placenta
3) two sublayers
i. stratum functionalis
ii. stratum basalis
b. myometrium – muscle layer
c. perimetrium – serosa
3. Cervix
D. Vagina
1. Birth canal
2. Lined with stratified squamous epithelium
E. Mammary glands
1. Modified sweat glands
2. Only functional in females
3. Produce milk to nourish newborn
4. Hormonal control (See A&P I Unit XI Endocrine System)
a. prolactin
b. oxytocin
E. Lathrop-Davis / E. Gorski / S. Kabr hel 175 Reproductive System
V. Oogenesis and the Ovarian Cycle Fig. 28.19, p. 1095
A. Oogonia develop into primary oocytes before birth Fig. 28.20, p. 1097
st th
B. Follicular phase – 1 to 14 day
1. Several primordial follicles becomes primary follicle
2. Single primary follicle becomes secondary follicle, normally
(sometimes more than one develop)
a. zona pellucida forms around oocyte
b. follicle begins to produce estrogens
c. antrum begins to form
3. Secondary follicle becomes Vesicular follicle (Graafian
follicle)
a. corona radiata forms
b. antrum enlarges
c. primary oocyte divides to form secondary oocyte and 1
polar body
C. Ovulation and Luteal phase – 14th to 28th day
1. Ovulation – release of secondary oocyte
2. Cells of ruptured follicle become corpus luteum which
continues to secrete progesterone and some estrogen
3. Corpus luteum degenerates in about 10 days if pregnancy
does not occur becomes corpus albicans
D. Hormonal control of ovarian cycle (See A&P I Unit XI
Endocrine System) Fig. 28.21, p. 1098; Fig. 28.22, p. 1100
1. Hypothalamus secretes GnRH
2. GnRH stimulates release of FSH and LH from anterior
pituitary
a. FSH (and LH) stimulate follicle growth
3. Enlarged follicles begin to secrete estrogens
a. rising estrogen levels initially inhibit release of FSH &
LH, but also stimulate it to produce and accumulate
these hormones
4. Once estrogen levels reach critical level, exert positive
feedback on hypothalamus & pituitary
a. result is sudden surge of LH
1) surge of LH results in completion of meiosis I and
release of secondary oocyte from vesicular
(Graafian) follicle
E. Lathrop-Davis / E. Gorski / S. Kabr hel 176 Reproductive System
2) surge of LH causes ruptured follicle to become
corpus luteum and stimulates production of
estrogens & progesterone
5. Increased progesterone and estrogen cause decline in LH;
corpus luteum is less stimulated and eventually becomes
corpus albicans
VI. Uterine (Menstrual) Cycle Fig. 28.22, p. 1100
A. Cyclical changes in the endometrium that prepare it for
implantation of a fertilized ovum.
B. Menstrual Phase (days 1-5)
1. Stratum functionalis shed
2. Response to reduced estrogen levels
C. Proliferative Phase (days 6-14)
1. Stratum functionalis rebuilt in response to stimulation
from ovarian estrogens
2. Endometrial glands begin to enlarge
3. Estrogen induces additional progesterone receptors
4. Blood supply increases
D. Secretory Phase (days 15-28)
1. Endometrium continues to develop in response to ovarian
progesterone
2. Endometrial gland cells secrete nutrients
3. Toward end, decline in progesterone results in declining
condition of blood vessels in stratum functionalis,
eventually resulting in its loss (start of next menstrual
phase)
VII. Disorders
A. Sexually transmitted diseases (STD)
1. Gonorrhea – infection by Neisseria gonnorrhoeae bacteria; causes inflammation
of the urethra and can lead to pelvic inflammatory disease in females
2. Syphilis – infection by Treponema pallidum bacteria
3. Chlamydia – infection by Chlamydia bacteria; causes pelvic inflammatory disease,
urethritis, among other things
4. Genital warts – infection by human papillovirus (HPV) ; causes warts in genital
area; can lead to cervical cancer
5. Genital herpes – infection by herpes simplex virus; causes lesions on genital area
E. Lathrop-Davis / E. Gorski / S. Kabr hel 177 Reproductive System
B. Pelvic inflammatory disease – inflammation of pelvic organs, usually caused by STD
C. Ectopic pregnancy – implantation of embryo outside uterus (e.g., in oviduct or pelvic
cavity)
D. Hypertrophy of prostate – enlargement of prostate, decreases size of prostate
urethra
E. Breast cancer – cancer of the mammary gland; strikes 1:8 women
E. Lathrop-Davis / E. Gorski / S. Kabr hel 178 Reproductive System
VIII. Important Developmental Milestones
A. 8 weeks
1. ossification begins
2. blood cells begin to be formed by liver
3. all systems present (at least as basic plan)
B. 9-12 weeks
1. bone marrow begins to form blood cells
C. 26 weeks
1. surfactant production begins in lung
D. 38-42 weeks
1. birth
a. if less than 38 weeks, systems not as developed
b. if more than 42 weeks, placenta starts to degrade
E. Lathrop-Davis / E. Gorski / S. Kabr hel 179 Reproductive System
TOPIC 13
Survey of Development
Ch. 29, pp. 1119-1145
Objectives
Pregnancy and Development
1. Define fertilization and explain how it occurs.
2. Describe cleavage, blastocyst formation, implantation.
3. Explain how the placenta arises.
4. List and describe the function of the four embryonic membranes.
5. List the three primary germ layers and give examples of structures that arise from
each.
6. Define organogenesis.
7. List the places where blood cell formation takes place in chronological order.
8. List the major milestones in fetal development and state the approximate time during
which they occur.
9. List the stages of parturition and tell what occurs during each.
Development of Selected Systems
1. Describe the important aspects of development for each of the body’s systems and
state the approximate time during which they occur.
Disorders
Describe the following disorders of development.
1. Anencephaly
2. Spina bifida
3. Infant Respiratory Distress Syndrome (RDS)
E. Lathrop-Davis / E. Go rski / S. Kabrhel 180 Survey of Develop ment
181
Topic 13: Survey of Development
I. Pregnancy
A. Events from fertilization to birth
B. Results from union of sperm & egg (fertilization)
C. Barriers to fertiliztion
1. acidity of male urethra
2. acidity of vagina
3. mucus plug
4. uterine contractions during orgasm
D. Fertilization – union of haploid gametes (egg & sperm)
produces diploid zygote
1. Penetration of egg – requires acrosomal enzymes of many
sperm to digest zona pellucida of egg Fig. 29.2, p. 1121
2. Union of sperm & egg membranes and nuclei – egg only
completes meiosis II if fertilized Fig. 29.3, p. 1122
E. Characteristics of living things – review from A&P I (Unit I
Introduction)
II. Pre-embryonic development – 1st through 2n d weeks
A. Cleavage – rapid replication of DNA and mitotic cell divisions
produce ever smaller cells Fig. 29.4, p. 1123
B. Blastocyst formation
1. Inner cell mass becomes future embryo
2. Trophoblast cells form part of placenta
C. Implantation – blastocyst implants itself into endometrium of
uterine wall
1. Ectopic pregnancy – implantation in another location Fig. 29.5, p. 1124
2. Trophoblast cells (blastocyst) secretes human chorionic
gonadotropin (hCG) that maintains corpus luteum through
1st four months Fig. 29.6, p. 1125
D. Placentation (development of placenta )
1. Formed by chorion of embryo and endometrium
2. Placenta begins to secrete estrogens and progestins
E. Lathrop-Davis / E. Gorski / S. Kabr hel 182 Survey of Development
III. Embryonic development – weeks 3-8
A. Development of embryonic membranes
1. Chorion
2. Amnion
a. produces amniotic fluid
b. amniotic fluid:
1) cushions embryo
2) maintains temperature
3) allows freedom of movement
3. Yolk sac
a. forms part of primitive gut
b. 1st site of blood cell formation
4. Allantois – forms part of umbilical cord and urinary bladder
B. Gastrulation - development of primary germ layers
1. Ectoderm – outmost – forms epidermis and nervous system
2. Endoderm – inner layer – forms epithelial linings of
digestive tract, respiratory tract, urogenital system and
associated glands
3. Mesoderm – middle layer – forms connective tissues and
muscle and limb buds
C. Organogenesis – development of organ systems
1. Heart beats by week 4
2. All systems present in some form by week 8
3. All major regions of brain present by week 8
4. Liver produces blood cells
IV. Fetal Development – Major Milestones See Table 29.2, p. 1138
rd
A. By 12 weeks (3 month)
1. Blood cell formation in bone marrow
2. Ossification begins (See A&P I)
a. endochondral ossification – in hyaline cartilage models
of most bones other than cranial bones and clavicles
b. intramembranous ossification – in flat bones of cranium
and clavicles
B. By 16 weeks
1. Kidneys have typical shape
2. Joint cavities present
E. Lathrop-Davis / E. Gorski / S. Kabr hel 183 Survey of Development
3. Cerebellum becomes large
4. Sensory organs differentiated
C. By 20 weeks
1. Skin covered by lanugo (silky hair)
2. Activity can be felt by mother (“quickening”)
D. By 30 weeks
1. Myelination of spinal cord begins
2. Finger and toe nails present
3. Bone marrow becomes only site of blood cell formation
4. Testes descend (7th month) in males
5. Surfactant production begins ~ 24 weeks
E. 8th to 9 th months
1. Continued development of organ systems
2. Significant weight gains
F. Weeks 38-42 – birth
1. Before 38 weeks, less fat, organ systems not as well
developed
2. After 42 weeks, placenta begins to degenerate
V. Development of Selected Systems
A. Integumentary system pp. 165-168
th
1. Epidermis and dermis developed by 4 month
2. Epidermal derivatives grow down into dermis
a. lanugo present from 20 weeks
b. vellus hairs present by 7th month
B. Skeletal system (See A&P I Unit XII Skeletal System) p. 181
th
1. Ossification begins by 8 week
a. primary ossification completed by birth; secondary
ossification continues to early adulthood
b. endochondral ossification occurs in hyaline cartilage;
intramembranous ossification occurs in flat bones
2. Fontanels – unossified membranes in skull at birth; allow
head to change shape slightly for easier birth
E. Lathrop-Davis / E. Gorski / S. Kabr hel 184 Survey of Development
3. Curvatures
a. primary curvatures – thoracic and sacral – present at
birth
b. secondary curvatures – cervical and lumbar – develop as
infant lifts head and stands, respectively
C. Nervous System (See A&P I Unit VI Brain and Cranial Nerves)
pp. 429-430, 463-464
1. Develops from “neural ectoderm”
a. neural crest cells (adjacent to tube) give rise to
sensory neurons
b. neural tube cells give rise to interneurons and motor
neurons
2. Eyes develop as outgrowth of diencephalon
3. Brain and spinal cord develop from neural tube
a. brain regions represent enlargements of anterior tube
anencephaly – failure of cerebrum and part of brain
stem to develop
b. ventricles develop from openings in neural tube
c. spinal cord develops from middle and posterior portions
of tube
spina bifida
1) incomplete fusion of vertebral arches, usually in
lumbrosacral region
2) up to 70% of cases associated with inadequate
folate levels in mother
3) some cases associated with UV radiation exposure
[DISCOVER Vol. 22 No. 2 (February 2001)]
D. Endocrine system
1. Complex development including all three germ layers
2. Two glands in particular develop from two different layers
a. pituitary – adenohypophysis develops from endoderm
(roof of primitive mouth) and neurohypophysis develops
from neural ectoderm as extension of diencephalon
(hypothalamus)
[http://calloso.med.mun.ca/~tscott/head/pit.htm]
b. adrenal gland – cortex develops from mesoderm and
medulla develops from neural ectoderm
E. Lathrop-Davis / E. Gorski / S. Kabr hel 185 Survey of Development
(http://sprojects.mmi.mcgill.ca/embryology/ug/Adrenal
_Stuff/Normal/zones.html)
E. Circulatory system
1. Blood (See Topic 1 Blood)
a. develops first in yolk sac, later in liver, spleen, bone
marrow
b. fetal hemoglobin has greater affinity for O 2
2. Heart pp. 709-710
th
a. begins as 2 tubes that fuse by 4 week
b. begins pumping in 1 st month (4th week)
c. foramen ovale allows blood to flow from right to left
atrium
1) moves oxygenated blood more quickly into general
circulation
2) by-passes developing lungs
3. Fetal circulation – special vessels (See Topic 3 Blood
Vessels) pp. 1135-1137
a. umbilical arteries – carry deoxygenated blood to
placenta
b. umbilical veins – returns oxygenated blood from
placenta
c. ductus venosus – connects umbilical vein to inferior vena
cava
d. ductus arteriosus – connects pulmonary trunk to aorta
F. Respiratory System pp. 877-878
1. Develops as buds from throat
2. Surfactant production begins in week 24
a. not produced in sufficient quantities until about week
32-35
b. infant respiratory distress syndrome (RDS) (See Topic
7 Respiratory System: Respiratory Disorders)
G. Digestive system pp. 938-942
1. Epithelium develops from endoderm; muscle develops from
mesoderm
2. Glands develop as buds from tube
H. Urinary system p. 1034
E. Lathrop-Davis / E. Gorski / S. Kabr hel 186 Survey of Development
1. Kidneys development begins in 4th week, completed by 9th
week
I. Reproductive system pp. 1104-1108
1. Ovaries & testes develop in abdominal cavity
a. differentiation begins during week 7-8
b. Testes descend into scrotum during 7th month
VI. Parturition (Birth)
A. Stages of labor
1. Dilation stage – cervix dilates to ~ 10 cm (4”)
2. Expulsion stage – delivery of fetus
3. Placental stage – delivery of placenta
B. Hormonal control of labor
1. Estrogen
2. Oxytocin
VII. Hormonal Control of Lactation
A. Prolactin
B. Oxytocin
E. Lathrop-Davis / E. Gorski / S. Kabr hel 187 Survey of Development
Biology 221 A&P I Review
The following are the major topics from A&P I that are important for you to remember.
Those of you who had me for A&P I (Biol220), already have a slightly longer version of this
list. Note that it’s pretty heavy on the review/early material. (And you thought you could
just forget your general biology. – Ha!) This is (obviously) not an all-inclusive list. It simply
represents the information that we will most likely use in A&P II. If you know these topics
at least superficially, you should be fine for both the review test and the rest of the
course.
Unit I – Introduction
Language of anatomy (lab), regional terms, body planes and sections, abdominal
regions and quadrants
Body cavities & membranes
Body fluids and compartments
Homeostasis, negative and positive feedback
Acids, bases, acid-base balance and pH
Macromolecules & their functions
Unit II – Histology
4 primary tissue types – general structure & major functions
Simple vs stratified epithelia
Important epithelial tissues, their general features and functions: simple squamous,
simple cuboidal, simple columnar, pseudostratified, stratified squamous, transitional
Important connective tissues, their general features and functions: areolar,
adipose, dense regular and irregular, elastic connective tissues; hyaline and elastic
cartilage; bone, blood
Types of muscle, their general features, locations and functions
Epithelial membranes (cutaneous, mucous, serous)
Types of cell junctions & their functions (see chapter 2)
Unit III – Integumentary System
Functions of skin
Major layers of skin
Major epidermal derivatives & their functions
Types of burns and their characteristics
Role of skin in thermoregulation
Unit IV – Nervous System Histology
Functions of nervous system
Types of neuroglia
Parts of a neuron
E. Lathrop-Davis / E. Gorski / S. Kabr hel 188 Survey of Development
Structural and functional classes of neurons
Functional classes of nerves
Definitions (p. 47)
Unit V – Electrophysiology
Parts of an action potential
Roles of Na + , K+ , and Ca2+ in graded potentials, action potentials (AP), synaptic
transmission
Voltage-gated vs chemically-gated channels
Graded potentials vs action potentials vs resting membrane potential
Role & action of Na+ /K+ pump
Saltatory vs continuous conduction
Intrinsic vs extrinsic factors affecting speed of AP conduction
Chemical vs electrical synapses
Parts of chemical synapse
Direct vs indirect modes of neurotransmitter (NT) action
Functional classifications of NTs
Termination of NT effects
Structural classes of NTs, especially ACh & catecholamines
Types of neuronal circuits, especially series, converging and diverging circuits
Unit VI – Brain and Cranial Nerves
Structures served by cranial nerves, especially facial, oculomotor, glossopharyngeal
& vagus
Foramina through which cranial nerves pass into/out of cranial cavity
Structure and role of blood-brain barrier
Structure and function of reticular formation
Control of ANS function, especially role of reticular formation & hypothalamus
Functions of the medulla oblongata, midbrain and pons, including control of heart
rate, blood vessels, respiration
Functions of hypothalamus, especially control of ANS and endocrine function
Unit VII – Spinal Cord and Tracts
Functions of spinal cord
Unit VIII – Spinal Nerves & Reflexes
Components of a somatic reflex arc
Unit IX – Autonomic Nervous System
Effects of sympathetic & parasympathetic innervation, especially at heart,
digestive organs, urinary system
Origins of sympathetic & parasympathetic preganglionic neurons
E. Lathrop-Davis / E. Gorski / S. Kabr hel 189 Survey of Development
Parasympathetic cranial nerves, the effectors each innervates, activities each
causes at the effector; especially the vagus
Types of receptors & effects of NTs & the drugs beta-blockers, neostigmine,
phentolamine, ephedrine on them
Role of sympathetic division in stress response (general adaptation syndrome) and
thermoregulation
Unit X – Special Senses
Special structures associated with each special sense and their locations
Nerves carrying impulses for special senses
Unit XI – Endocrine
General mechanisms of interaction between hormone and receptor cell, and
examples of hormones
General mechanisms of control of secretion and examples of hormones that are
controlled by each method
Major glands, their hormones, how those hormones are controlled, and what they
do; especially those that affect bone, muscle, glucose regulation, sodium/potassium
balance, blood pressure
Important disorders, especially the three types of diabetes and the 2 subtypes of
diabetes mellitus, and disorders of bone growth (gigantism, dwarfism, acromegaly)
and metabolism
Stages of general adaptation syndrome and the hormones involved in each
Unit XII – Skeletal System
Functions of bone
General characteristics of bone
Types of ossification
Bones of the axial skeleton and cranial foramina through which blood vessels pass
Unit XIII – Muscular System
Functions of muscle
General characteristics of muscle
Development of tension in skeletal muscle
Muscle metabolism
Features, control, excitation of smooth muscle
E. Lathrop-Davis / E. Gorski / S. Kabr hel 190 Survey of Development
