Three stages of blood clotting are-
Stage 1; Formation of prothrombin activator
Stage 2; Conversion of prothrombin into enzyme thrombin
Stage 3: Conversion of Fibrinogen (soluble) to fibrin (insoluble)
Stage 1; Formation of Prothrombin Activator
Formation of prothrombin activator; prothrombin can be formed in 2 ways-
1. Intrinsic pathway
2. Extrinsic pathway
1. Intrinsic pathway (5-10 min) inside vascular system
After comming in contact with collagen fibres or rconnective tissues inside blood, it will lead to activation of-
Factor XII
Factor XI
Factor XII + Factor XI
Factor IX
Factor VIII
Factor VIII + Calcium ion + Factor III
Factor X
Factor V
Factor X + Factor V
Prothrombin activator/Prothrombinase
2. Extrinsic pathway (15-20sec)
Activated through tissue factor released by endothelial cell after external damage.
Tissue damage
Tissue thromboplastin activates -
(Factor III)
Factor VII
Factor X
Factor V
Factor X + Factor V
Prothrombin activator + Prothrombinase
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