in Body Fluids and Circulation (Cardiovascular System, Circulatory system) by

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Platelets or thrombocytes are small, irregularly shaped, non nucleate structures containing red-purple granules.

The normal platelet count is (150 – 400) × 103 per mm3.

The life span of the platelets is around 7 - 10 days.

The principal role of the platelets is haemostasis (prevent bleeding)

Haemostasis is done in two ways:

  1. By adhesive and cohesive functions, platelets lead to the formation of haemostatic plugs.
  2. By activating coagulation mechanisms 


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The most important physical property of platelets is the maintenance of Hemostasis, and it depends on three factors

  1. The endothelial supporting function of platelets,
  2. The ability to form hemostatic plugs and
  3. To release lipoprotein material (platelet factor 3).

When these circulating platelets get reduced, the capillary endothelium gets weak, because the platelets are not available to enter the endothelial cytoplasm for the support. And hence, the capillary walls gets ruptured when expose to trauma. The bleeding through the damaged capillary walls is arrested by the aggregation of the platelet making a hemostatic plug. This is the main function of the platelet or the most important physical property of the platelet.

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