• Platelets are?fragments of cells which are involved in blood clotting?and forming scabs where skin has been cut or punctured
• Blood clotting?prevents continued / significant blood loss?from wounds
• Scab formation seals the wound with an insoluble patch that?prevents entry of microorganisms?that could cause infection
• It remains in place until new skin has grown underneath it, sealing the skin again

How the blood clots

• When the skin is broken (i.e. there is a wound) platelets arrive to stop the bleeding
• A series of reactions occur within the blood plasma
• Platelets release chemicals that cause?soluble fibrinogen proteins?to convert into?insoluble fibrin?and form an?insoluble mesh?across the wound, trapping red blood cells and therefore?forming a clot
• The clot eventually dries and develops into a?scab?to protect the wound from bacteria entering

轉載自savemyexams