39 Questions
Which of the following can activate platelets?
Endothelial injury
What is the main function of platelets in hemostasis?
To seal damaged vessels
What can cause platelets to activate?
Activation by other activated platelets
Which cells synthesize Von Willebrand Factor (vWF)?
Endothelial cells
Where is Von Willebrand Factor (vWF) stored in endothelial cells?
Weibel-Palade bodies
What is the main function of platelets in hemostasis?
Seal openings in vascular tree
True or false: Platelets adhere to the sub-endothelium during hemostasis?
True
True or false: Platelet aggregation involves the binding of platelets to each other?
True
True or false: Von Willebrand Factor (vWF) is released by activated platelets and endothelial cells?
True
True or false: Von Willebrand Factor (vWF) is a carrier protein for factor VIII?
True
True or false: Von Willebrand Factor (vWF) binds platelets to damaged endothelium?
True
True or false: Von Willebrand Factor (vWF) binds activated platelets together (aggregation)?
True
True or false: Von Willebrand Factor (vWF) acts as a carrier protein for factor VIII?
True
True or false: Von Willebrand Factor (vWF) binds platelets to damaged endothelium?
True
True or false: Von Willebrand Factor (vWF) binds activated platelets together for aggregation?
True
Which factor is released in the presence of thrombin?
Factor VIII
What is the role of Von Willebrand Factor (vWF) in hemostasis?
It binds activated platelets together for aggregation
What is the function of Von Willebrand Factor (vWF) in platelet adhesion?
It binds platelets to damaged endothelium
Which of the following is true about membrane glycoproteins?
They are made up of amino acids and glucose molecules
What is the role of GPIb in platelet adhesion?
It binds to vWF
What binds to subendothelial collagen during hemostasis?
vWF
Which receptor is the most abundant on platelets' surface?
GPIIb/IIIa receptor
What happens to the GPIIb/IIIa receptor during platelet activation?
It changes conformation
When does the GPIIb/IIIa receptor bind?
When platelets are activated
Which protein does GPIIb/IIIa bind to in order to link platelets together?
Fibrinogen
What is the basis for IIB/IIIA receptor blocking drugs?
Platelet aggregation
What is the main function of GPIIb/IIIa receptor in platelet aggregation?
Linking platelets together
Which type of platelet granules is the most abundant?
Alpha granules
Which substances are released from alpha granules upon platelet activation?
Fibrinogen, von Willebrand factor, and platelet factor 4
What stimulates platelet activation and secretion of stored activators?
Stimulation by activating substances
Which protein is released from alpha granules and binds to endothelial cells?
Platelet Factor 4 (PF4)
What is the rare, life-threatening effect of heparin administration?
Heparin-induced thrombocytopenia
What happens when antibodies bind to PF4 complexed with heparin?
Platelet activation
Which receptors does Adenosine Diphosphate (ADP) bind to on platelets?
P2Y1 and P2Y12
Which of the following drugs inhibit platelet activity by blocking ADP receptors?
Clopidogrel, prasugrel, ticlopidine, ticagrelor
Which molecule is a powerful platelet activator and has receptors on platelets?
Thromboxane A2 (TXA2)
Which test involves making a small cut to the patient's arm and applying/removing filter paper until bleeding stops?
Bleeding Time Test
What is the purpose of the Bleeding Time Test?
To measure platelet function
Is the Bleeding Time Test commonly performed in the modern era?
No, it is rarely done
Test your knowledge about platelets and their role in hemostasis with this quiz! Learn about how platelets circulate in an "inactive" form and can become "activated" due to various factors such as endothelial injury and stimuli from other activated platelets. Discover how these activated platelets help seal damaged vessels and aid in the process of hemostasis after vascular injury.
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