Fibrinolysis

Question 1

Identify the mechanisms that limit the size of the clot

Answer 1

1. Vasodilation and washout of TxA2.
2. Antithrombin inactivates 2a as well as 9a, 10a, 11a and 12a.
3. Tissue factor pathway inhibitor neutralizes tissue factor.
   
   1. Protein C and S inhibit factor 5a and 8a.

Question 2

Fibrinolysis is?

Answer 2

The process of clot breakdown

Question 3

______ is a proenzyme synthesized in the liver, is incorporated in the clot and lays dormant until it’s reactivated.

Answer 3

Plasminogen

Question 4

___________ is a proteolytic enzyme that degrades fibrin into fibrin degradation products.

Answer 4

Plasmin

Question 5

Describe 3 mechanisms of plasmin activation

Answer 5

1. tPA is released by injured tissue over a period of 3 days.
2. Urokinase is produced by the kidneys and released into the circulation.
3. Streptococci secrete streptokinase.
   
   1. Use of plasmin activators therapeutically.

Question 6

How is Fibrinolysis turned off

Answer 6

• tPa inhibitors inhibit conversion of plasminogen to plasmin
• Alpha-2 antiplasmin inhibits the action of fibrin.