Process of blood clotting
The chart across shows the process of blood clotting;
When blood vessels are injured, the platelets are exposed to air causing them to rapture. They release thromboplastin
(thrombokinase) which initiates the clotting process. Thromboplastin neutralizes heparin and activates conversion of prothrombin to thrombin. Calcium ions are required for this process. Thrombin catalyzes the conversion of fibrinogen (soluble protein) to fibrin(insoluble). Fibrin forms a meshwork of fibers on the cut surface which trap red blood cells forming a clot.