When a vessel wall is damaged, blood flow out of the vessel is arrested by way of a complex series of interrelated physiological and biochemical processes. There are a wide variety of factors that influence the effectiveness of hemostatic processes including the following:
- Type of, and degree of, vessel damage
- Ability of vasoconstriction to occur
- Availability of platelets & their functionality
- Availability of clotting factors & their functionality
- Absence of inhibitors and anticoagulants
The image on the right illustrates vessel size as related to time required for clotting to occur, amount of coagulation products used (platelets and clotting factors), and size of the corresponding bleed.