Coagulation Cascade

Question 1

What are the steps of the intrinsic pathway up to the common pathway?

Answer 1

12->12a activating 11->11a activating 9->9a 9a+8a+Ca+ activate 10->10a

Question 2

What are the steps factor XII does in intrinsic pathway?

Answer 2

Binds to prekallikrein-HMWK-Ca2+ complex on negatively charge endothelium which releases kallikrein, kallikrein then activates HMWK into bradykinin

Question 3

What is bradykinin?

Answer 3

A vasodilator needed to allow immune cells to flow to the affected wound

Question 4

What are two ways for XI to be activated?

Answer 4

Thrombin or 12a

Question 5

What are the steps in the extrinsic pathway?

Answer 5

Tissue factor activates 7->7a 7a+Ca2+ activates 10->10a

Question 6

What are the steps in the common pathway?

Answer 6

10a+5a+Ca2+ activates 2 (prothrombin) -> 2a (thrombin) 2a (thrombin) + 13 + 1 -> 1a + 13a, 1a + 13a-> Fibrin matrix

Question 7

What is 1a?

Answer 7

Unstable fibrin matrix

Question 8

Where is von Willebrand factor (vWF) found?

Answer 8

Bound to factor 8

Question 9

What is vWF needed for?

Answer 9

Factor 8 has a very short half life so it is needed to stabilize it

Question 10

What cleaves vWF from factor 8?

Answer 10

Thrombin

Question 11

What breaks the clot down?

Answer 11

Plasmin

Question 12

What steps does thrombin accelerate?

Answer 12

5
7
8
11
13

Question 13

How does vWF interact with collagen?

Answer 13

Binds to exposed collagen to allow platelets to aggregate on endothelium

Question 14

How do clots contract?

Answer 14

Actin and myosin fibers are produced to contract (non muscular)

Question 15

What activates plasminogen?

Answer 15

Tissue plasminogen activator (tPA) produced by vascular endothelium

Question 16

What is the plasminogen activator in the kidney?

Answer 16

Urokinase-type plasminogen

Question 17

How is plasmin inactivated once it leaves the broken down clot?

Answer 17

Alpha 2 antiplasmin

Alpha 2 macroglobulin

Question 18

What is the purpose of plasminogen activator inhibitor-2?

Answer 18

Stops the plasmin from being activator to disallow clot breaking down too fast in pregnancy and hemorrhaging

Question 19

What is indicative of a clot being broken down?

Answer 19

D-dimers found in fibrin degradation products

Question 20

What is tissue factor pathway inhibitor?

Answer 20

Plasma protein that binds and inhibits the complex of tissue factor Ca2+ and factor 7a complex

Question 21

What is antithrombin III?

Answer 21

Plasma glycoprotein that inhibits 9a, 10a, 11a, 12a and is enhanced by heparin (very negative inhibits thrombin)

Question 22

What is thrombomodulin?

Answer 22

Glycoprotein that complexes with thrombin to remove it from acting as a catalyst; also activates protein C

Question 23

What does protein C do?

Answer 23

Binds with protein S to activate it and inhibit thrombin slowing down clotting cascade

Question 24

What is vitamin K needed to synthesize?

Answer 24

2, 7, 11, 10, C, S

Question 25

What does vitamin K do?

Answer 25

Post-translational modifications to proteins/factors carboxylic acid group added

Question 26

What does warfarin/Coumadin do?

Answer 26

Inhibits vitamin K regeneration