BIOM 2000 Lecture Notes - Lecture 14: Hemostasis, Blood Vessel, Endothelium
16 Mar 2016
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Document Summary
Stoppage of bleeding, resulting form a break in a blood vessel (not wound healing, hemo means first step in wound healing, stops bleeding) Hemostasis involves 3 phases: vascular spasms, platelet plug formation, coagulation (blood clotting) Undamaged blood vessel: platelets do not interact with the lining of the blood vessel. Damaged blood vessel: platelet respond to expose connective tissue and release chemicals onto their surface that makes them stick to the inner wall of the blood vessel. Injury, pain and damage to smooth muscles and endothelial cell lining cause blood vessels to spasm. Step 2: platelet plug forms, platelets release chemicals that make nearby platelets sticky, and promote further vasoconstriction. Step 3: coagulation events occur (injured tissues release tissue factor, which initiates clotting cascade, fibrin forms a mesh that traps red blood cells and platelets, forming the clot. Coagulation events: inactive proteins are activated in the blood and form meshwork that traps cells and forms clot.
