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Biology 2402 Human Anatomy and Physiology
RESPIRATORY SYSTEM
LMobley 2008
I. Introduction: Parts of the system
A. upper: conduction = nose and head through the larynx
1. the epiglottis belongs to the _________
B. lower: conduction = trachea, lungs
C. respiratory = alveoli = exchange
D. terms:
ventilation- internal and external
respiration of gases
atmosphere
cells
E. respiratory rates based on the expulsion of CO2
(The tissue need for O2 drives HR and CO.)
1. The direction of the carbonic acid buffer reaction is determined by the pCO2
2. In tissue capillaries, where pCO2 is high, H+ and HCO3- are formed. In pulmonary capillaries, where
pCO2 is low, CO2 and H2O are formed.
II. Nose
A. structures as marked in lab
B. function (nasal conchae)
1. warm
2. olfaction
3. resonate for sound
III. Pharynx
A. three part – note the hard and soft palates
B. function = common passageway for air and food
IV. Larynx
A. structures as marked
B. voice production
vestibular folds (false) (close the epiglottis)
VOCAL folds (true), skeletal muscles contract, ligaments tight, stretch the folds into airway, air against
them => vibrations = sound waves
tighter the folds higher the pitch; thinner in females = higher pitch; males more mass = thicker = lower
pitch
other oral structures = resonate chambers for shaping sound; vowels
Where do consonants come from?
V. Trachea
A. structures
1. C-rings
2. divides at carina
B. function - air and dust, bacteria, etc.
VI. Bronchi and bronchioles
A. respiratory tree or bronchial tree
1. changes in epithelium, cartilage, smooth muscle
2. secondary and tertiary bronchi have overlapping plates of cartilage (not rings)
B. parasympathetic - constriction of bronchioles (asthma - revived by NE (sympathetic to vasodilation))
C. bronchioles – no cartilage, decreasing amounts of SM and cilia
D. Functions
Biol 2402 respiratory notes ltm updated 4/16/08 1
1. expand air ways
2. control air in/out
VII. Lungs
A. cavities and membranes - review pleural and serous, etc.
B. structures
1. # lobes and fissures
2. details --see diagrams, models, lab manual
C. function - O2 and CO2 exchange
D. alveoli
1. surfactant = phospholipids and lipoproteins which lower the surface tension of alveolar fluid (mostly
water) to prevent collapse of lungs
2. macrophages as reapers of debris
3. note the discussion of surfactant – definition and alveolar I and II cells
E. membrane layers (4) the width of one RBC; surface area = to handball court
F. blood supply -- review
PART B
RESPIRATORY PHYSIOLOGY
I. Respiration
A. respiration - using O2 metabolically
relationship with/to CO2 _________________
B. ventilation - process and the mechanical aspects of breathing
II. Ventilation = Mechanisms of breathing -- based on pressure changes
A. Inspiration
1. need for O2
2. increased need for more air
3. diaphragm contracts and goes down; external intercostals contract and lift lungs up and out
4. intra pleural pressure changes from 760 mm Hg -- decreases
5. eupenea, costal breathing, diaphragmatic breathing
6. lasts about 2 seconds normally
B. Expiration
1. passive (no muscle contraction) unless disease or stress
2. internal intercostals and abdominal muscles contract only during labored exhalation
3. lasts about 3 sec normally
C. Collapsed lung
1. loss of surfactant
D. Compliance and Resistance = elasticity and surface tension (disease and obstruction)
1. alveolar surface tension
2. alveolar ventilation
a. dead air space and dead air in the conducting parts (non alveolar)
E. Modified respiratory movements - in lab - p.
1. speaking, laughing, sneezing, etc.
III. Measurement of pulmonary air volumes - in lab + on lecture test
A. Volumes: define
B. Pulmonary capacities
C. Anatomic dead air space = no exchange of gases in the ____
Biol 2402 respiratory notes ltm updated 4/16/08 2
IV. Neural control of ventilation (separate section in outline – Part C)
V. Exchange of Respiratory gases – based on pressure changes
A. three gas laws = standard natural laws for molecules
1. Boyles -- P== 1/V
2. Charles V=T
3. Dalton's= sum of partial pressures: know %age of each gas in the air
partial pressure = pressure of that gas at a particular percentage i.e. 21 % x 760mmHg = 159 mm
Hg or 13.7 x 760 mmHg = 104 mm Hg
4. Henry's = quantity of gas that dissolves in liquid is proportional to partial pressure and solubility
coefficient. Accounts for pressure changes in the ocean, at sea level and in space
B. External respiration:
1. pO2 with decrease atmospheric pressure = O2 into blood
2. surface area for O2 - CO2
3. distance for diffusion (four layers)
4. rate and depth = mVR = minute ventilation rate
C. Internal Respiration = O2 out of blood into capillaries
1. Basics - oxygenated becomes deoxygenated
2. 25% us of O2 at normal times == only 25% used: WHY??
VI. Transportation of gases
A. 1.5% in plasma + 98.5% on hemoglobin == function of blood (RBC)
B. Hb + O2 => HbO2 (oxyhemoglobin, oxidized)
C. determined by pO2 , CO2 , temp, and BGP (or DGP)
1. Fig.
2. acidity and pCO2 = inc. pH then more O2 on hemoglobin
dec. pH , dec. O2 (sat'd = caused to split)
3. temp
4. BGP causes O2 to dissociate from hemoglobin; intermediary in glycolysis p/ 829
D. Hypoxia = low level of O2 availability
E. CO2
1. dissolved CO2 (molecular)
2. Hb + CO2 <=> HbCO2 easily split off in lungs
3. carbonic acid buffer reaction and the chloride shift - to maintain ionic balance between plasma and
RBC (Cl- into RBC
VII. Summary
A. Equation p.
1. CO2 gas
2. CO2 + Hb
3. HCO3- (+Cl-)
B. Haldane effect opposite to Bohr effect
(Haldane = lower the PO2 and the hemoglobin saturation with oxygen, the more CO2 carried in the blood)
C. all breathing depends on pCO2 which is produced in response to the tissue need for O2; and it (CO2)must be
eliminated.
Biol 2402 respiratory notes ltm updated 4/16/08 3
Part C: CONTROL OF RESPIRATION
I. Control location
A. medulla and pons
B. thoracic size controlled by respiratory center (reticular formation in brain stem)
C. three groups of neurons
1. medullary rhythmicity
2. pneumotaxic in pons
3. apneustic in pons (area is still hypothetical) – functions not well known
II. The three groups
A. Medullary rhythmicity area
1. 2 in, 3 ex (2 seconds in and 3 second expiration)
2. send impulses to diaphragm via phrenic for inspiration -- review mechanism
contract external intercostals and diaphragm
3. reverse for expiration: but by passive elastic recoil of lungs and thoracic wall
4. in high ventilation, internal intercostals contract as well as abdominal muscles
B. Pneumotaxic: shuts off intake to allow for expiration
C. Apneustic area: overrides pneumotaxic to prolong inspiration and inhibit expiration
III. Respiratory center regulation -- in response to body demands.
A. respiratory center modified by nerve impulses sent to the center
pulmonary irritant reflexes (stimulate via vagus nerve)
1. chemoreceptors
2. aortic bodies and carotid bodies (see below)
B. Cortical influences
1. protective voluntary control for short periods
2. but build up of CO2 and H+ override and respiratory center is stimulated and you breathe == drown, or
baby breath holding
3. blood brain barrier -- CO2 and O2 cross and carbonic acid is formed; no buffering proteins
C. Inflation reflex: prevents too much inflation
1. Herring-Breuer reflex - autonomic visceral reflex
2. stretch receptors respond to inflation
3. inhibit the apneustic area and an expiration follows
D. Chemical regulation: maintain correct levels of CO2 and O2
1. carotid bodies (between ext. and internal carotid art) and aortic bodies (in arch of aorta) sensitive to
oxygen
2. aortic = vagus; carotid = glossopharyngeal
3. hyperventilation = rapid and deep breathing, loss of CO2
anxiety attacks, dizziness, faint (recover by breathing into paper bag)
4. hypoventilation = slow and shallow breathing = retention of CO2 mostly during disease
E. Proprioceptors - in anticipation of exercise
F. Other influences
1. temperature increase causes increase in breathing
2. pain - increase respiratory rate
3. anal sphincter stretch
4. irritations of air passages
Biol 2402 respiratory notes ltm updated 4/16/08 4
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