Editing Coagulation (section)

====Cell-based scheme of coagulation====
A newer model of coagulation mechanism explains the intricate combination of cellular and biochemical events that occur during the coagulation process ''[[in vivo]]''. Along with the procoagulant and anticoagulant plasma proteins, normal physiologic coagulation requires the presence of two cell types for formation of coagulation complexes: cells that express tissue factor (usually extravascular) and platelets.<ref>{{Cite journal |vauthors=Hoffman MM, Monroe DM |date=September 2005 |title=Rethinking the coagulation cascade |journal=Curr Hematol Rep |volume=4 |issue=5 |pages=391–96 |pmid=16131441}}</ref>

The coagulation process occurs in two phases. First is the initiation phase, which occurs in tissue-factor-expressing cells. This is followed by the propagation phase, which occurs on activated [[platelet]]s. The initiation phase, mediated by the tissue factor exposure, proceeds via the classic extrinsic pathway and contributes to about 5% of thrombin production. The amplified production of thrombin occurs via the classic intrinsic pathway in the propagation phase; about 95% of thrombin generated will be during this second phase.<ref name="Hoffman-2003">{{Cite journal |last=Hoffman |first=M. |date=August 2003 |title=Remodeling the blood coagulation cascade |journal=Journal of Thrombosis and Thrombolysis |volume=16 |issue=1–2 |pages=17–20 |doi=10.1023/B:THRO.0000014588.95061.28 |pmid=14760207 |s2cid=19974377}}</ref>