Injury exposes collagen; von Willebrand factor recruits platelets. They activate, swell, and form the primary plug within seconds.
Extrinsic (tissue factor) and intrinsic pathways converge at Factor X. Thrombin converts fibrinogen to fibrin, creating a reinforcing mesh.
Plasminogen→plasmin dissolves the clot (fibrinolysis). Balance between coagulation and fibrinolysis prevents thrombosis and hemorrhage.