Coagulation ppt

Question 1

What are the 3 ways to achieve hemostasis (arrest of bleeding)

Answer 1

1. vascular contraction (vasospasm)
2. Platelet adhesion, activation and aggregation
3. Fibrin formation and reinforcement of the platelet plug (coagulation)

Question 2

what happens when there is a break in the wall

Answer 2

Damage to BV endothelium –> reduce prostacyclin PGI2 (an inhibitor of platelet adhesion), releases vWF and exposes collagen –> binding of receptors –> enables GP11b/IIIa to undergo confirmational change that allows it to bind to circulating fibrinogen. Fibrinogen forms crosslinks bw platelets. Binding of platelets to collagen activates bound platelets to release ADP, thomboxane A2 and serotonin 5HT

Question 3

What do ADP, Thromboxane A2 and Serotonin 5HT do?

Answer 3

ADP: inducer of platelet activation
TXA2: vasoconstriction and platelet activation
Serotonin 5-HT: vasoconstriction and platelet aggregation

Question 4

what goes on simultaneously with platelet adhesion/activation/aggregation

Answer 4

Coagulation cascade.. starts with activation of intrinsic pathway by exposure of TF

Question 5

What happens upon exposure of TF in coagulation cascade

Answer 5

Exposed TF –> binds and activates factor VII –> binds and activates factor X –> converts prothrombin to thrombin which cleaves fibrinogen to fibrin