SZABMU AHS 2026 Blood Free Quiz 6

1. What is the source of von Willebrand factor?

A. Synthesized by hepatocytes B. Synthesized by endothelial cells and platelets C. Synthesized by lymphocytes D. Synthesized by erythrocytes

2. Which molecule, released from platelets, promotes further platelet aggregation?

A. ATP B. ADP C. Thromboxane A2 D. Serotonin

3. Which enzyme is responsible for thromboxane A2 synthesis and is inhibited by aspirin?

A. COX-1 (aspirin target) B. COX-2 C. LOX D. Phospholipase A2

4. What is the effect of prostacyclin on platelets?

A. Promotes aggregation B. Inhibits aggregation C. Promotes vasoconstriction D. Inhibits vasodilation

5. Which selectin is found on activated platelets and facilitates leukocyte recruitment?

A. E-selectin B. P-selectin C. L-selectin D. ICAM-1

6. What is the mechanism of heparin?

A. Antithrombin III B. Plasminogen C. Tissue factor pathway inhibitor (TFPI) D. Protein C

7. Which enzyme is targeted by warfarin?

A. Vitamin K epoxide reductase B. Gamma-glutamyl carboxylase C. Cytochrome P450 D. NADPH oxidase

8. What is the role of protein C and protein S?

A. Activate factors Va and VIIIa B. Inactivate factors Va and VIIIa C. Activate thrombin D. Inhibit plasminogen

9. What is the defect in factor V Leiden?

A. Activated protein C resistance B. Prothrombin mutation C. Antithrombin deficiency D. Factor VIII deficiency

10. Which laboratory test detects fibrin breakdown, indicating clot formation and lysis?

A. Platelet count B. D-dimer C. PT/APTT D. Fibrinogen