Edexcel IGCSE Biology

Revision Notes

2.8.7 Human Transport Systems: Platelets


  • Platelets are involved in helping the blood clot
  • Platelets are fragments of cells that are involved in blood clotting and forming scabs where the skin has been cut or punctured
  • 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

How the blood clots, IGCSE & GCSE Biology revision notes

How the blood clots

The importance of blood clotting

  • 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

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Ruth graduated from Sheffield University with a degree in Biology and went on to teach Science in London whilst also completing an MA in innovation in Education. With 10 years of teaching experience across the 3 key science disciplines, Ruth decided to set up a tutoring business to support students in her local area. Ruth has worked with several exam boards and loves to use her experience to produce educational materials which make the mark schemes accessible to all students.

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