BIOM 4090 Lecture Notes - Lecture 5: Vitamin K Deficiency, Factor Vii, Von Willebrand Disease
13 Apr 2018
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Document Summary
Hemostasis is a process that keeps the blood fluid and clot-free in normal vessels and also forms a localized plug in injured vessels. An injured blood vessel must induce the formation of a blood clot to prevent blood loss and to allow healing. Clot formation must also remain localized to prevent widespread clotting within intact vessels. Therefore, the goal of normal hemostasis can be summarized as preventing prolonged hemorrhage and spontaneous thrombosis. The formation of a localized clot at the site of vessel injury is accomplished in four temporally overlapping stages: vascular spasm or localized vasoconstriction is the first response to injury. The damaged vessel immediately constricts in order to restrict or reduce the blood flow to the area to limit the amount of blood loss. This response occurs as a result of secretion of endothelium-derived vasoconstrictors such as endothelin.
