Platelets & Blood Clotting (Edexcel IGCSE Biology)

Platelets

Spec point — 3.14B · understand how platelets are involved in blood clotting, which prevents blood loss and the entry of micro-organisms

• 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