Platelet Production, Structure, and Function

Question 1

1. The megakaryocyte progenitor that undergoes endomitosis is:
   a. MK-I
   b. BFU-Meg
   c. CFU-Meg
   d. LD-CFU-Meg

Answer 1

d. LD-CFU-Meg

Question 2

2. The growth factor that is produced in the kidney and induces growth and differentiation of committed megakaryocyte progenitors is:
   a. IL-3
   b. IL-6
   c. IL-11
   d. TPO

Answer 2

d. TPO

Question 3

3. What platelet organelle sequesters ionic calcium and binds
   a series of enzymes of the eicosanoid pathway?
   a. G protein
   b. Dense granules
   c. DTS
   d. SCCS

Answer 3

c. DTS

Question 4

4. What platelet membrane receptor binds fibrinogen and
   supports platelet aggregation?
   a. GP Ib/IX/V
   b. GP IIb/IIIa
   c. GP Ia/IIa
   d. P2Y1

Answer 4

b. GP IIb/IIIa

Question 5

5. What platelet membrane phospholipid flips from the inner
   surface to the plasma surface on activation and serves as the
   assembly point for coagulation factors?
   a. Phosphatidylethanolamine
   b. Phosphatidylinositol
   c. Phosphatidylcholine
   d. Phosphatidylserine

Answer 5

d. Phosphatidylserine

Question 6

6. What is the name of the eicosanoid metabolite produced
   from endothelial cells that suppresses platelet activity?
   a. TXA2
   b. Arachidonic acid
   c. Cyclooxygenase
   d. Prostacyclin

Answer 6

d. Prostacyclin

Question 7

7. Which of the following molecules is stored in platelet
   dense granules?
   a. Serotonin
   b. Fibrinogen
   c. PF4
   d. Platelet-derived growth factor

Answer 7

a. Serotonin

Question 8

8. What plasma protein is essential to platelet adhesion?
   a. VWF
   b. Factor VIII
   c. Fibrinogen
   d. P-selectin

Answer 8

a. VWF

Question 9

9. Reticulated platelets can be enumerated in peripheral
   blood to detect:
   a. Impaired production in disease states
   b. Abnormal organelles associated with diseases such as
   leukemia
   c. Increased platelet production in response to need
   d. Inadequate rates of membrane cholesterol exchange
   with the plasma

Answer 9

c. Increased platelet production in response to need

Question 10

10. Platelet adhesion refers to platelets:
    a. Sticking to other platelets
    b. Releasing platelet granule constituents
    c. Providing the surface for assembly of coagulation factors
    d. Sticking to surfaces such as subendothelial collagen

Answer 10

d. Sticking to surfaces such as subendothelial collagen