When the skin is cut, we lose blood and there is a site for pathogens to enter our bloodstream, making us vulnerable to infection. To prevent this from happening, the body quickly forms a blood clot which allows the wound to close up.Platelets are a small type of blood cell which play an important role in the clotting process. When they come into contact with air or damaged cells, as in a wound, they release an enzyme responsible for converting soluble fibrinogen proteins in blood plasma to insoluble fibrin. Fibrin is 'sticky' and creates a large mesh across the wound which traps some red blood cells. Platelets that have formed clumps also get trapped in the mesh. The trapped red blood cells form a clot which develops into a scab. The scab covers the wound as it heals, preventing blood loss and protecting it from the outside.