The Blood Coagulation And Fibrinolytic Pathways: Effectors and Co-factors Flashcards
What is the coagulation cascade?
It’s an amplifying series of enzymatic conversions, each step proteolitically cleaves an inactive proenzyme into an active enzyme culminating in thrombin formation
What role does thrombin play in the cascade
- amplifies its own production
- converts soluble fibrinogen into fibrin monomers which polymerize into an insoluable gel
What is fibrin gel responsible for forming?
The definitive secondary hemostatic plug (in which platelets and other circulating cells are encased)
Describe the difference between the intrinsic and extrinsic pathways of blood coagulation
Intrinsic - contact with blood and some of it’s enzymes is sufficient to trigger the reaction
Extrinsic - components of plasma are not sufficient, tissue factor is needed
Where do the instrinsic and extrinsic pathways converge?
The production of factor 10
Step by step describe the intrinsic pathway
- Factor 12 is activated by kallikrein at the top
- factor 12a activates factor 11
- factor 11a activates factor 9
- factor 9a complexes with factor 8a (activated by thrombin) and this complex activates activates factor 10
- factor 10a complexes with factor 5a (activated by thrombin) to activate prothrombin to thrombin
Which 3 factors in the intrinsic pathway cause Hemophilia if mutated
Factor 8 - Hemophilia A
Factor 9 - Hemophilia B
Factor 11 - Hemophilia C
Describe the extrinsic pathway’s activation of thrombin
- It begins with the formation of a complet between Tissue Factor and factor 7a
- This complex activates factor 10 to 10a
- 10a converts prothrombin into thrombin
What is the aim of the fibrinolytic process?
To stop clot formation and dissolve the platelet plug
Plasminogen is activated to _______ by ___________ or by _____________
Plasmin
TPA - tissue plasminogen activator
Urokinase plasminogen activator
