* * *Process of forming a blood clot to prevent blood loss from a ruptured vessel.A damaged blood vessel stimulates activation of clotting factors, eventually leading to the formation of long, sticky threads of fibrin. These make a mesh that traps platelets, blood cells, and plasma. This meshwork soon contracts into a resilient clot that can withstand the friction of blood flow. Under abnormal circumstances, clots can form in an intact vessel and may block it. See also anticoagulant.
* * *in physiology, the process by which a blood clot is formed. The formation of a clot prevents blood loss from a ruptured blood vessel. Under abnormal circumstances, clots can also form in a vessel that has not been breached; such clots can result in the occlusion of the vessel.Clotting is a sequential process that involves the interaction of numerous blood components called coagulation factors. Among the better-known factors are fibrinogen (see fibrin) and prothrombin (q.v.) (factors I and II) and antihemophilic globulin (factor VIII). There are 13 principal coagulation factors in all, and each of these has been assigned a Roman numeral up to XIII.The first step in coagulation is the formation of prothrombin activator. This substance forms in response to compounds released by the damaged vessel wall. Prothrombin activator also forms in response to changes in the blood itself; these changes result from the blood contacting the collagen fibres of the ruptured vessel.Once formed, prothrombin activator initiates the conversion of prothrombin to thrombin. Thrombin, in turn, catalyzes the conversion of fibrinogen (fibrin)—a soluble plasma protein—into long, sticky threads of insoluble fibrin. The fibrin threads form a mesh that traps platelets, blood cells, and plasma. Within minutes, the fibrin meshwork begins to contract, squeezing out its fluid contents. This process, called clot retraction, is the final step in coagulation. It yields a resilient, insoluble clot that can withstand the friction of blood flow.
* * *
Look at other dictionaries:
coagulation — [ kɔagylasjɔ̃ ] n. f. • 1360; de coaguler ♦ Précipitation de particules en suspension dans un liquide (⇒ coagulum), causée par le chauffage, l addition d un acide ou une réaction de condensation. La coagulation du blanc d œuf, de la caséine du… … Encyclopédie Universelle
Coagulation — Co*ag u*la tion, n. [L. coagulatio.] 1. The change from a liquid to a thickened, curdlike, insoluble state, not by evaporation, but by some kind of chemical reaction; as, the spontaneous coagulation of freshly drawn blood; the coagulation of milk … The Collaborative International Dictionary of English
coagulation — COAGULATION. s. f. Terme didactique. L état d une chose coagulée, ou l action par laquelle elle se coagule. La coagulation du sang. La coagulation du lait … Dictionnaire de l'Académie Française 1798
coagulation — Coagulation. s. f. v. L estat d une chose coagulée. La coagulation du sang. le lait ne luy est pas bon, il s en fait une coagulation dans son estomac … Dictionnaire de l'Académie française
coagulation — index adhesion (affixing), agglomeration, coalescence, congealment Burton s Legal Thesaurus. William C. Burton. 2006 … Law dictionary
coagulation — c.1400, from L. coagulationem (nom. coagulatio), noun of action from pp. stem of coagulare (see COAGULATE (Cf. coagulate)) … Etymology dictionary
coagulation — [n] clotting agglomeration, caseation, concentration, concretion, condensation, congelation, consolidation, curdling, embolism, gelatination, incrassation, inspissation, jellification, thickening; concept 469 Ant. dissolution, melting, opening,… … New thesaurus
Coagulation — This article is about blood clotting. For other meanings see Coagulation (disambiguation). Coagulation is a complex process by which blood forms clots. It is an important part of hemostasis, the cessation of blood loss from a damaged vessel,… … Wikipedia
Coagulation — In medicine, the clotting of blood. The process by which the blood clots to form solid masses, or clots. More than 30 types of cells and substances in blood affect clotting. The process is initiated by blood platelets. Platelets produce a… … Medical dictionary
Coagulation — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Un phénomène de coagulation existe lorsque certains constituants d une masse liquide (lait, sang, etc.) s agglutinent pour former une masse plus compacte… … Wikipédia en Français