CIE IGCSE Biology: 复习笔记:9.1.17 Conversion of Fibrinogen: Extended

CIE IGCSE Biology: 复习笔记:9.1.17 Conversion of Fibrinogen: Extended

Conversion of Fibrinogen: Extended

  • 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

转载自savemyexams

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