platelet

-small and oval biconcave cells

• -non nucleated cells

  Cell size 2-3 pico m

  -has special contractile proteins-thrombosthinin,actin and myosin 

  Normal count-2-4 lakh /mm

  Thrombo cytopenia-dengue fever -decrease in platelets

  Thrombocytosis  increase in platelets-post surgery

  Life span- 7-8 days

  Formation-pleuripotent sten cell-megakaryocytesbits of cytoplasm separates-platelets

  Function:-helps in heamostasis 

  
  

  Platelet plug formation:-

  Injury of blood cells

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  Exposed collagen

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  Platelet  show adhesion

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  Activation of platelets

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  Plate aggregation

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  Plugging of injured vessels

  
  
  

  Release of thromboplastin-for blood coagulation

  -release of platelet derive growth factor-for repairing

  -release of of serotonin

  -release of von widibrand factor