Physiology, Hemostasis

In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024 Jan.


Definition. Hemostasis is the mechanism that leads to cessation of bleeding from a blood vessel. It is a process that involves multiple interlinked steps. This cascade culminates into the formation of a “plug” that closes up the damaged site of the blood vessel controlling the bleeding. It begins with trauma to the lining of the blood vessel.

Stages. The mechanism of hemostasis can divide into four stages. 1) Constriction of the blood vessel. 2) Formation of a temporary “platelet plug." 3) Activation of the coagulation cascade. 4) Formation of “fibrin plug” or the final clot.

Purpose. Hemostasis facilitates a series of enzymatic activations that lead to the formation of a clot with platelets and fibrin polymer. This clot seals the injured area, controls and prevents further bleeding while the tissue regeneration process takes place. Once the injury starts to heal, the plug slowly remodels, and it dissolves with the restoration of normal tissue at the site of the damage.

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