The mechanism is activated by thrombin, which is active form of prothrombin. Prothrombin is converted to its active form, thrombin activator in the presence of ionic Ca2+.
Antithrombin-III is an alpha globulin, which shows antithrombin action. It removes thrombin from blood.
Heparin is an anticoagulant, which is produced by the basophilic mast cells located in the pericarpillary connective tissue through out the body. They usually secrete small amount of heparin that diffuses into the circulatory system.
