Human Biology F221

Human Bio blood clotting and first aid to prevent excess blood loss


blood clotting

Blood clotting:

  • damaged tissues expose collagen to the air 
  • blood platelets become trapped in the fibres making other platelets sticky
  • the tissues and damaged platelets release the enzyme thromboplastin 
  • thromboplastin coverts the blood protein prothrombin into an active enzyme thrombin
  • thrombin converts the blood protein fibrinogen into long insoluble fibrin fibres 
  • the fibres form a mesh that traps blood cells to form a blood clot 
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first aid

prevent excessive blood loss by:

  • sit the person down raise the damaged limb e.g arm or leg 
  • check for foreign objects in the wound 
  • if nothing is there place a pad over it 
  • if something is there do not remove it as this could cause more bleeding 
  • cut the pad around the wound, if the blood soaks the pad dont change it, add another on top as this could disturb the healing process 
  • seek proper medical help
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