2.64B understand how platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms

Platelets: cell fragments involved in blood clotting.
Function: clot the blood to prevent further blood loss and clotting prevents entry of harmful bacteria that can infect wound or cause diseases.

 Process:
-When skin is wounded, platelets arrive to wound and break open.
-When calcium ions are present, thrombin will be formed. Thrombin will act on fibrinogen, and turn it into fibrin, which is a mass of insoluble protein thread that clots and traps RBC.
-Clot will develop into a scab and allow the wound to heal.