Prevention of Inappropriate Coagulation

Prevention of Inappropriate Coagulation - in the plasma. At...

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Prevention of Inappropriate Coagulation For coagulation to be effective it must be rapid and accurate . Inappropriate coagulation can result in blood clots, strokes or heart attacks . Several mechanisms prevent inappropriate blood clot formation. Platelets generally only become sticky when exposed to the collagen in the underlying connective tissues. Furthermore, platelets do not adhere to the prostacyclin coating on the innermost layer of blood vessels. Therefore, as long as the endothelial layer of blood vessels remains undamaged, platelets are not stimulated to become sticky and aggregate together. Once activated by tissue damage, platelets stimulate coagulation at the site of damage. Clot formation away from the site of damage is prevented by the dilution of thrombin in the systemic circulation and the presence of antithrombin
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Unformatted text preview: in the plasma. At increasing distances from the damaged area, the amount of activated thrombin present will decrease because of dilution and the activity of antithrombin, decreasing the amount of fibrin formation. Fibrinolysis Immediately following clot formation, tissue repair mechanisms are activated. Platelet-derived growth factor secreted by platelets stimulates mitotis in fibroblasts and smooth muscles to repair the damaged vessel. Afer tissue repair, the clot becomes unnecessary, and possibly dangerous. Fibrinolysis is the process by which fibrin clots are dissolved. Kallikrein and factor XII activate the plasma protein plasminogen . Plasminogen is converted into plasmin , a fibrin-dissolving enzyme, that breaks down the fibrin net....
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