How does blood clotting occur?

This is a rather complicated process, during which special biologically active substances are released from destroyed platelets, damaged vessels.
When the vessel is damaged, the platelets that are in this place are destroyed and release prothrombin, which transfers the soluble plasma protein fibrinogen to the insoluble protein fibrin. Long filaments of fibrin are intertwined into a network in which blood elements are trapped, and a blood clot forms, which blocks the wound and prevents bleeding. Over time, the vessel is restored and the clot disappears.