Hemostasis & Thrombosis Flashcards
What are the 4 phases of hemostasis?
- vasoconstriction
- formation of platelet plug at site of injury
- cascade of zymogen activation
- dissolution of clot by plasmin
What is hemostasis?
where blood flow stops
What is the intrinsic pathway in the blood clotting cascade?
- all clotting factors involved
- damage to endothelium exposes collagen that binds to platelets and initiates clotting
- factors: 9,8 -> 10
What is the extrinsic pathway in the blood clotting cascade?
- one factor involved comes from outside circulation
- trauma to blood vessel causes release of factor 3 into blood to initiate clotting
- factors: 3, 7 -> 10
How is prothrombin (2) turned into thrombin (2a)?
factors 10a + 5a + Ca + phospholipids
How is fibrinogen turned into fibrin?
cleavage of A and B fibrinopeptides
What does the conversion of glutamate to gamme-carboxyglutamate require?
vitamin K & protein carboxylase
What enzyme is responsible for glutamine and lysine forming the fibrin clot?
transglutaminase (factor 13a)
What factor plays a role in fibrinogen turning into fibrin?
thrombin
What are the inhibitors of clotting?
- vitamin K antagonists -> dicoumarol & warfarin
- aspirin
- heparin/antithrombin
What is the process of heparin/antithrombin?
- antithrombin (+) binds to heparin (-)
- thrombin (+) binds to heparin (-)
- thrombin & antithrombin come together
In the prothrombinase complex, what factors are involved?
- 10a
- 5a
- Ca
- phospholipids
What is the role of plasmin?
breaks down fibrin
What is the role of tPA?
activates plasmin
What is the kringle domain?
region of tPA binds the fibrin clot