Lab Blood and Cardiovascular System by nikeborome


									                             Lab06: Blood and Cardiovascular System

Anatomy. Label each of the structures indicated on the heart diagram [last page] and identify the corresponding
structures on the plastinated hearts. Know the precise functions of all of the indicated structures. If a vessel is
indicated, understand which anatomical structures or general areas of the body it supplies. Trace the flow of blood
through the heart, valves, and vessels using both the diagrams and the plastinated hearts. Find the coronary
arteries and veins on plastinated hearts. What is the function and clinical significance of these vessels?
Auscultation. Use the stethoscope to listen to your partner’s heart. What is a physician listening for as she listens
to your heart? What makes the sounds that you are hearing? Why to the sounds come in pairs (lubb-dupp)? What
causes the first sound and what causes the second sound of the heartbeat? Why would a cardiologist tend to place
the stethoscope on four different areas? What else is the stethoscope used for during an examination?
Histology. Compare the histology of cardiac muscle with skeletal muscle. On the cardiac muscle, note that the
muscle cells are striated, comparatively small, and generally have a single nucleus. Identify the intercalated disks,
which are junctions between adjacent cardiac muscle fibers that enable an action potential to spread between cells.
Notice that skeletal muscle fibers are also striated, but they are larger and non-branching, with multiple nuclei in
each fiber (cell). Skeletal muscle fibers do not have specialized junctions between them, so each individual skeletal
muscle fiber requires stimulation from a neuron in order to contract. The intercalated disks of cardiac muscle fibers
enable the contraction of one muscle fiber to stimulate its neighboring fibers to contract, which creates a chain-
reaction wave of muscle contraction through the heart during each heartbeat. Attempt to find blood vessels that
supply the muscle tissue on each of these slides.

Understand the general differences between veins, venules, capillaries, arterioles, and arteries (table below).
Study the microscope SLIDE of the vein, artery and nerve. Identify the different layers that are found in the large
vessels [tunica externa, tunica media, tunica interna, endothelium]. Which layer is made of smooth muscle? Find
these layers on the slide, and examine the morphological differences between the artery and the vein. Use the table
below to summarize some of the important anatomical and functional differences between arteries, veins and
capillaries [this is very, very important to me]. Why is blood usually drawn from a vein, not an artery?

                                          Artery                          Vein                        Capillary
 Size of lumen
 Thickness of vessel wall
 Direction of blood flow

Also study the HYPERTENSION MODEL of the hypertensive artery & understand the physical changes in the
artery associated with hypertension. You can also use this model to identify and review the different layers of the
vessels. What parts of the vessel are most affected? Does hypertension have its greatest effect on arteries or veins,
or are the equally affected? Why is hypertension a problem?
Examine the ARTERIOSCLEROSIS MODEL and understand the structures and changes that are represented.
Refer to your text for a discussion of arteriosclerosis. Why is arteriosclerosis a problem? Are there different kinds
of arteriosclerosis?
Pulse. Find and record your pulse at both the wrist (radial artery, on the lateral side of the forearm just proximal to
the wrist) and in the neck (carotid artery, on either side of the neck, just lateral to the larynx). When clinicians take
your pulse, they are checking three major variables: (1) Heart rate – beats per minute, (2) rhythm – regularity in the
heart rate, versus speeding up and slowing down or skipping beats and (3) tension – if the pulse is firm and strong,
or relatively weak. What does each of these variables tell you about cardiovascular function?

                            Lab06: Blood and Cardiovascular System

Using yourself or your partner, find your pulse in other areas – temporal, brachial at elbow and in arm, radial, and
dorsalis pedis (you can palpate the popliteal pulse if you have exposed knees, and the femoral & axillary pulses if
you are daring). What are you actually feeling as you feel the pulse? Why are the areas where you take the pulse
also important areas for controlling extreme bleeding? Does the pulse rate differ in these areas? What is the
minimum error you can expect if you take a pulse for 6 seconds; 10 seconds? Why should you never use your thumb
to take a pulse? Listen to these different areas with a stethoscope – what do you hear when you listen to the pulse?

Use the prepared slides to study the histology of blood. Identify the different types of formed elements in the blood
(erythrocytes, leukocytes, platelets). What is the function of each of these? Which is the most common formed
element? Why are these things called ‘formed elements’ and not ‘cells’? Scan around the slide to find the other
components of blood: platelets, neutrophils, basophils, eosinophils, monocytes, and lymphocytes. Count 50
WBCs and record the numbers of each.

                        Count      % of WBCs      My description of shape

Pathological blood samples
•   Select a slide representing a reaction to an infectious disease process (mononucleosis, lymphocytosis, or
    leukocytosis) and conduct a similar count of white cells. Is the absolute number of white cells increased? Are
    the proportions of white cell types different than in normal blood?
•   Next, select a slide of leukemia – either acute granulocytic leukemia (myleogenous leukemia) or acute
    lymphocytic leukemia (this slide is bone marrow, not blood). What is leukemia (generally)? What is
    happening (going wrong) on your slide? Which cells are affected and how?
•   Examine a slide of sickle cell anemia. Which cell(s) are affected and how? Are all of the cells affected? How
    could you quantify the changes in sickle cell anemia from what you see in the slide?
•   Examine our lone slide of a thrombus (clot). Describe what is going on throughout this slide.
•   Examine the slide of frog blood. How does frog blood differ from mammalian blood? This is one of the
    distinct characteristics of mammals – no other group of animals has it.

The Complete Blood Count (CBC) is a common hematological screening test, which is used to diagnose and
manage numerous diseases. During this procedure, about 5-7 mL of blood is drawn from a vein, usually from the
inside of the elbow or the back of the hand. The CBC includes the following measurements:
    •    The number of red blood cells (RBCs)
    •    The number of white blood cells (WBCs)
    •    The total amount of hemoglobin in the blood
    •    The fraction of the blood composed of red blood cells (hematocrit)
    •    The mean corpuscular volume (MCV) -- the size of the red blood cells
    •    these are used to calculate MCHC (Mean Corpuscular Hemoglobin Concentration)
    •    platelet count and mean platelet volume (size) is usually included in the CBC

The CBC can reflect problems with fluid volume or loss of blood. CBC can indicate abnormalities in the production,
life span, and rate of destruction of blood cells, reflect acute or chronic infection, allergies, and help identify
problems with clotting or anemia.

                               Lab06: Blood and Cardiovascular System

A few other compounds that are commonly measured in blood include:
•   Glucose (blood sugar)
•   HbA1C– over time (~4 weeks), glucose will bind to hemoglobin, forming HbA1C or “glycated hemoglobin”.
    Once attached, glucose is not easily detached from the hemoglobin. Therefore, A1C levels provide information
    concerning averge blood sugar levels from the past ~ month.
•   Cholesterol including Total Cholesterol; HDL, and LDL [High- (good), Low-density (bad) Lipoproteins]
•   Creatinine is produced from creatine in muscle. Normally, about 2% of your creatine is converted to
    creatinine, carried in the blood to the kidneys, where it is expelled. Elevated creatinine levels in the blood
    usually indicate kidney failure (reduced clearance) rather than muscle damage (increased production).
•   Creatine Phosphokinase (CPK) accumulation in the blood indicates muscle damage. Different subtypes of
    CPK indicate damage to skeletal muscle (CPK-MM), heart (CPK-MB), or brain (CPK-BB).

                                             Patient #1   Patient #2   Patient #3   Patient #4   Patient #5   Patient #6

RBCs                        4.20 - 5.70         4.36        3.94         5.42         4.66            5.99      4.51
                             x106 /mm3

WBCs                      3,900 - 10,000        4,400       8,200       17,500        7,100           9,000     5,500

Hb (hemoglobin)           13.2 - 16.9 g/dL      15.5        12.8         14.5          9.2            18.8      15.2
Hematocrit                 38.5 - 49.0%         55.5        42.0         48.2         39.5            51.2      40.1
MCV                         80 – 97 μm   3
                                                 82         85.0             88        78              91        88
MCHC                       32.0 - 36.0%         32.3        32.4         35.7         22.5            34.5      32.6
                            140,000 -
Platelets                                    185,000      365,000      220,000      191,000      400,000      380,000
                           390,000 mm3
Mean Platelet Vol.        7.5 - 11.5 μm3         8.5        11.2          9.4          8.1            10.2      13.5
Glucose                    70-100 mg/dL          57          135             80        140             95        66
HbA1C                       4.0 – 5.9%           5.1         8.8          5.1          5.5             4.6       5.0
Creatinine                 0.8-1.4 mg/dL         0.9         1.3          2.2          1.1             1.3       1.0
CPK-MM                       0-36 U/l            15             3            28         6              37        25
Serum cholesterol         150-240 mg/dL         215          278          190          208            160        203

Use the above table to answer these questions:
    •       Which patient has a bacterial infection? Can you tell which kind of infection?
    •       Which patient might have iron-deficiency anemia?
    •       Which patient might have anemia from bleeding?
    •       Which patient would be dehydrated?
    •       Which patients might be at elevated risk of heart attack due to diet? …due to genetics?
    •       Who is hypoglycemic?
    •       Which person might be a blood-doping athlete?
    •       Which person likely has diabetes?
    •       Which person ate a candy bar before their fasting blood tests?

Lab06: Blood and Cardiovascular System




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