BIOM 4090 Lecture Notes - Lecture 5: Adenine, Thrombus, Sterol
25 Jan 2018
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Document Summary
Drugs used in the treatment of disorders of the blood. 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. Sympathetic and local factors (thromboxane) are also released which initiates the myogenic properties in the vessel wall and induces smooth muscle contraction: immediately following vasoconstriction, primary hemostasis occurs which involves platelet activation to form the initial plug. In this stage, platelets adhere to the exposed collagen of the damaged endothelium and also to each other. The platelet plug releases chemical mediators (such as txa2, 5-ht and adp) which are responsible for recruiting more platelets, promoting vasoconstriction and initiating the coagulation cascade.
