Process of forming a blood clot to prevent blood loss from a ruptured vessel.
A damaged blood vessel stimulates activation of clotting factors, eventually leading to the formation of long, sticky threads of fibrin. These make a mesh that traps platelets, blood cells, and plasma. This meshwork soon contracts into a resilient clot that can withstand the friction of blood flow. Under abnormal circumstances, clots can form in an intact vessel and may block it. See also anticoagulant .