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Renin Angiotensin Mechanism.

Haemostasis.

  Haemostasis.

  • It is defined as the process of stopping of bleeding and involves many steps like following,

  1. Vasoconstriction:

  • When damage to the blood vessel takes place many chemicals causing vasoconstriction are released which causes vasoconstriction.

  • The activated platelets start aggregating.

  1. Platelet plug formation:

  • The platelets which are stuck near the injury site releases chemicals which attract more platelets.

  • More platelets come and adhere with each other forming a plug which prevents further blood loss.

  • The formed plug is weak hence to make blockade more powerful blood starts clotting.

  1. Coagulation (blood clotting):

  • It is a complex process involving many steps.

  • On damage to blood vessels platelets release “Thromboplastin”.

  • Thromboplastin activates inactive “Prothrombin” to activate “Thrombin” in plasma.

  • Thrombin activates inactive “Fibrinogen” to activate “Fibrin”.

  • The formed fibrin threads intangle with each other to form a mesh.

  • The blood cells get trapped in the fibrin mesh to form a clot.

Commonly Asked Questions.

  1. Write a note on Haemostasis.
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