CELLULAR AND IMMUNE CONCEPTS
VICKI SWEET, INSTRUCTOR
OCTOBER 22, 2012
I decided to write my paper about the coagulation system, including clot formation, but mainly about Disseminated Intravascular Coagulation. Disseminated Intravascular Coagulation, also known as DIC, is a pathological activation of blood clotting mechanisms that may happen in response to a variety of diseases, or illnesses. However, DIC, is most commonly observed in severe sepsis and septic shock. DIC is not a specific illness, rather it is a complication or an effect of the progression of other illnesses or diseases. (Porth, 2011). When the body becomes injured, certain proteins in your blood become activated and travel to the injury site to help stop bleeding and control hemostasis. Hemostasis is the normal process of sealing off a blood vessel to prevent blood loss and hemorrhage. It is abnormal when it fails to appropriately clot the blood, or when this clotting is insufficient to stop the bleeding. Following an injury, there is an immediate vessel spasm that promotes vasoconstriction, which tries to diminish the blood flow. Collagen from the damaged site, releases platelets which adhere to the damaged vessel, and there, they undergo degranulation and release cytoplasmic granules, ADP, Thromboxane A2, and Serotonin which is a vasoconstrictor. The ADP then attracts more platelets to the area, and the Thromboxane A2 promotes platelet aggregation, degranulation, and even more vasoconstriction. This process promotes the formation of a platelet plug. The damaged tissue now releases Factor III (3), which, with the aid of Ca++, will activate Factor VII (7), which initiates the extrinsic mechanism of clotting. Factor XII (12), which comes from active platelets, will activate Factor XI (11), which initiates the intrinsic mechanism. Both active Factors VII (7), and active Factors XI (11), promote a cascade-like reaction, eventually activating Factor X (10)....
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