Clotting Cascade Flashcards
What is Factor Ia?
Activated Fibrin.
What is Factor IIa?
Activated thrombin.
What is Factor IIIa?
Tissue factor, which is released in extrinsic cellular damage that causes the conversion of Factor VII -> Factor VIIa.
What is the intrinsic pathway?
Factor XII -> Factor XIIa
Factor XI -> Factor XIa
Factor IX-> Factor IXa which causes factor X -> Factor Xa which combines with Factor V to convert prothrombin to thrombin.
What is the extrinsic pathway?
Tissue factor (Factor III) is released due to extracellular damage. It causes Factor VII -> VIIa. This activates Factor Xa to combine with Factor Va and form prothrombin.
How is the extrinsic pathway inhibited?
Tissue factor pathway inhibitor which prevents the formation of the complex TF-Factor VIIa.
What is protein C?
Responsible for acting with protein S to inhibit Factor V and Factor VIII.
What causes the breakdown of fibrin?
Plasmin. Tissue plasminogen activator causes plasminogen -> plasmin.
What enables platelet adhesion to injury site?
Von Willebrand factor- this is produced by endothelial cells which allow attachment to exposed collagen of the tunica media for platelets.
How does platelet activation occur?
ADP receptors and release of inflammatory mediator thromboxane, from the cyclo-oxygenase pathway.
How does platelet aggregation?
GPiib/iiia receptor
-> This is activated by ADP action on P2Y12 receptor
What is the role of anti-thrombin?
Inhibits Factor Xa and thrombin.
How does clopidogrel work?
ADP antagonist.
How does aspirin work?
Inhibits COX-1 for the arachiodionic acid pathway that produces thromboxane.
How does LMWH work?
Activates anti-thrombin to selectively target Factor Xa only.
