Britannica
Sources used in this answer
What are the four main stages of the hemostatic process?
Created from Britannica articles
using AI.
AI can make mistakes, so verify using Britannica articles.
bleeding and blood clotting
Red blood cells (erythrocytes) trapped in a mesh of fibrin threads. Fibrin, a tough, insoluble protein formed after injury to the blood vessels, is an essential component of blood clots.
The normal hemostatic response to vascular injury is organized into four distinct stages:1
- Initial vasoconstriction: The blood vessel narrows to minimize blood loss at the site of injury.1
- Platelet plug formation: Platelets aggregate on and around the lesion to form a temporary plug.1
- Activation of coagulation: A series of biochemical reactions occurs, involving various coagulation factors, which leads to the formation of a stable fibrin meshwork.12
- Activation of fibrinolysis: The process by which the fibrin clot is eventually dissolved by the enzyme plasmin once the vessel has healed.13