Platelets & Blood Clotting (Edexcel IGCSE Biology): Revision Note

Platelets

• Platelets are fragments of cells that are involved in blood clotting and forming scabs

  • 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

    • This forms an insoluble mesh across the wound

    • Red blood cells become trapped, forming a clot

    • The clot eventually dries and develops into a scab

• This process helps to prevent excessive blood loss and protect the wound from bacteria entering until new skin has formed

How the blood clots