RESUMO
Coagulation is the whole of enzymatic reactions leading in transforming plasma into a gel primarily made up of fibrin to consolidate the clot formed during primary hemostasis. Fibrin derived from the enzymatic cleavage of fibrinogen by thrombin, a key enzyme of coagulation. The classic design of coagulation describes two different pathways: intrinsic and extrinsic. In fact these two ways are overlapping since passages exist between them. In this work we are interested in the current concept of coagulation physiology by underlining the place of the cellular reactions in this phenomenon. The phenomena of coagulation take place either in circulation, or on a cellular surface. The effectiveness of the enzymes implied in coagulation is much larger on a cellular surface than in plasma, bringing to conceive coagulation like a cellular phenomenon. Recently, this cellular conception of coagulation resulted in proposing a new sight of coagulation which would proceed in three phases: initiation, amplification, propagation