GENERAL MECHANISM OF BLOOD COAGULATION -
All researchers agree that blood clotting is a cascade mechanism and involves three essential steps - (a) Formation of prothrombin activator. It is formed in two ways :
Extrinsic pathway -
(b) Conversion of prothrombin into thrombin -
(c) Conversion of fibrinogen into fibrin -
Fibrinogen Fibrin Threads (insoluble)
Fibrin threads form a meshwork which traps blood cells and platelets to form a clot so the process is called blood clotting. Within a few minutes, the clot begins to contract and a pale coloured fluid called serum is discharged. This is called clot-retraction.