Coagulation Cascade Flashcards
What are the steps of the intrinsic pathway up to the common pathway?
12->12a activating 11->11a activating 9->9a 9a+8a+Ca+ activate 10->10a
What are the steps factor XII does in intrinsic pathway?
Binds to prekallikrein-HMWK-Ca2+ complex on negatively charge endothelium which releases kallikrein, kallikrein then activates HMWK into bradykinin
What is bradykinin?
A vasodilator needed to allow immune cells to flow to the affected wound
What are two ways for XI to be activated?
Thrombin or 12a
What are the steps in the extrinsic pathway?
Tissue factor activates 7->7a 7a+Ca2+ activates 10->10a
What are the steps in the common pathway?
10a+5a+Ca2+ activates 2 (prothrombin) -> 2a (thrombin) 2a (thrombin) + 13 + 1 -> 1a + 13a, 1a + 13a-> Fibrin matrix
What is 1a?
Unstable fibrin matrix
Where is von Willebrand factor (vWF) found?
Bound to factor 8
What is vWF needed for?
Factor 8 has a very short half life so it is needed to stabilize it
What cleaves vWF from factor 8?
Thrombin
What breaks the clot down?
Plasmin
What steps does thrombin accelerate?
5 7 8 11 13
How does vWF interact with collagen?
Binds to exposed collagen to allow platelets to aggregate on endothelium
How do clots contract?
Actin and myosin fibers are produced to contract (non muscular)
What activates plasminogen?
Tissue plasminogen activator (tPA) produced by vascular endothelium
What is the plasminogen activator in the kidney?
Urokinase-type plasminogen
How is plasmin inactivated once it leaves the broken down clot?
Alpha 2 antiplasmin
Alpha 2 macroglobulin
What is the purpose of plasminogen activator inhibitor-2?
Stops the plasmin from being activator to disallow clot breaking down too fast in pregnancy and hemorrhaging
What is indicative of a clot being broken down?
D-dimers found in fibrin degradation products
What is tissue factor pathway inhibitor?
Plasma protein that binds and inhibits the complex of tissue factor Ca2+ and factor 7a complex
What is antithrombin III?
Plasma glycoprotein that inhibits 9a, 10a, 11a, 12a and is enhanced by heparin (very negative inhibits thrombin)
What is thrombomodulin?
Glycoprotein that complexes with thrombin to remove it from acting as a catalyst; also activates protein C
What does protein C do?
Binds with protein S to activate it and inhibit thrombin slowing down clotting cascade
What is vitamin K needed to synthesize?
2, 7, 11, 10, C, S
What does vitamin K do?
Post-translational modifications to proteins/factors carboxylic acid group added
What does warfarin/Coumadin do?
Inhibits vitamin K regeneration
