Weight: 5%
Minimum Pass Grade: 50%
Each question is worth 10 marks.
1. Fill in the words or phrases that best complete each sentence. Be as specific as possible.
Answer:
a. Erythrocytes contain the enzyme carbonic anhydrase, which catalyzes the conversion of metabolically
produced CO2 and water into carbonic acid.
b. Most old erythrocytes are removed from circulation and destroyed by cells called macrophages, as they
rupture passing through the narrow capillaries of the organ called the spleen.
c. Undifferentiated cells called pluripotent stem cells reside in the bone marrow, where they continuously
divide and differentiate to give rise to each of the types of blood cells.
d. The process of leukocytes squeezing through the capillary endothelial cells pores to exit the vasculature
is known as emigration or diapedesis. Once they leave the bloodstream to fight a pathological condition,
they never return.
e. The genetically-determined glycoprotein and glycolipid antigens found on the surface of an erythrocyte
are called agglutinogens, and a person with agglutinins that react with type A and blood type B has type
O blood.
f. During embryonic development, ninety-nine percent of the cardiac fibers are specialized for the function
called purkinje fibers, whereas the remainder is specialized for autorhythmic function.
g. The action potential delay at the atrioventricular node ensures that atrial excitation and contraction are
complete before ventricular excitation and contraction commence.
h. The end-systolic volume is the volume of blood in the ventricle after ejection has been completed. An
increase of this volume occurs when the stroke volume is at rest.
i. The three cations, K+, Ca2+, and Na+ have an important effect of heart function. Increased blood levels of
Na+ blocks Ca2+ inflow and results in a decrease in the force of contraction, while an excess of K+
blocks the generation of action potentials.