Hemostasis Review (MEDL 279) - Platelets

Platelets are produced from which type of cell?

• Megakaryocytes

• Erythrocytes

• Lymphocytes

• Monocytes

What percentage of platelets are found in the spleen?

• 10%

• 30%

• 50%

• 70%

What is the basic reference range for platelet count per mm3?

• 150-450,000/mm3

• 50-100,000/mm3

• 500-1,000,000/mm3

• 10,000-50,000/mm3

What is the typical lifespan of platelets?

• 9-12 days

• 1-2 days

• 20-25 days

• 30-40 days

Which glycoprotein binds to exposed collagen during platelet adhesion?

• Glycoprotein Ib

• Glycoprotein IIb/IIIa

• Glycoprotein VI

• Glycoprotein Ia/IIa

Von Willebrands factor is required for which process in hemostasis?

• Adhesion of platelets

• Activation of fibrinogen

• Synthesis of thrombin

• Degradation of clot

What is the first phase of platelet aggregation?

• Fibrinogen binding links the platelets

• Platelets release serotonin

• Platelets contract to form a plug

• Thrombin converts fibrinogen to fibrin

Secreting platelets release arachidonic acid, which converts to what in the platelet?

• Prostaglandin

• Serotonin

• Histamine

• Dopamine

Which components are included in platelet release during the assembly and localization of the fibrin clot?

• Fibrinogen, Factor V, Factor VIII

• Collagen, ADP, Thrombin

• Prostaglandin, Arachidonic acid, ADP

• Glycoprotein Ib, Fibrinogen, Collagen

Which factor is the substrate in the plasma coagulation process?

• Factor I (fibrinogen)

• Factor II

• Factor V

• Factor VIII