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What are the four stages of the hemostatic process that stops bleeding?
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wound
Injuries that break skin can be painfully memorable.
The normal hemostatic response to damage in the vascular endothelium occurs in four distinct stages to stop bleeding and facilitate the healing of a wound:
- Initial vasoconstriction: The blood vessel contracts and narrows to minimize blood loss at the site of the injury.1
- Platelet aggregation: Platelets adhere to the lesion and to each other, forming a platelet plug that blocks the flow of blood from the vessel.1
- Activation of coagulation: A series of reactions occurs involving blood-clotting proteins, leading to the development of bundles of fibrin fibers that reinforce the platelet plug.12
- Activation of fibrinolysis: Once the vessel is repaired, the enzyme plasmin is activated to dissolve the fibrin clot, which is eventually replaced by a permanent framework of scar tissue.13