ANATOMY & PHYSIOLOGY HEALTH & DISEASE A  B  C  D  E  F  G  H  I  J  K  L  M  N  O  P  Q  R  S  T  U  V  W  X  Y  Z                    HOME ABOUT CATEGORIES SITE MAP COPYRIGHT ADVERTISE CONTACT entire Web this site blood clotting When an injury causes a blood vessel wall to break, platelets are activated. They change shape from round to spiny, stick to the broken vessel wall and each other, and begin to plug the break. They also interact with other blood proteins to form fibrin. Fibrin strands form a net that entraps more platelets and blood cells, producing a clot that plugs the break. © Merck A protective mechanism that prevents excessive blood from being lost after an injury. In the clotting process, a mesh of tight fibers of the protein fibrin coagulates at the site of injury through a series of chemical reactions. This mesh traps blood cells to form a clot, which dries to forma scab. This prevents further loss of blood, and also prevents bacteria getting into the wound. Normal clotting takes place within five minutes. In some diseases, such as hemophilia, the clotting mechanism is impaired. Related categories    • ANATOMY AND PHYSIOLOGY    • HEALTH AND DISEASE Also on this site: Encyclopedia of Alternative Energy & Sustainable Living Encyclopedia of History Transport Concepts & Designs (partner site) BACK TO TOP