Secondary hemostasis

The formation of a fibrin clot.

The subendothelial tissue factor is exposed leading to activation of the procoagulant cascade and eventual formation of a fibrin clot.

Following vascular injury tissue factor is exposed which activates the procoagulant cascade: factor VII activated to factor VII a-tissue factor complex which activates factor X to factor Xa and factor IX to IXa. Factor IXa with factor VIIIa as a cofactor activate factor X to factor Xa. Factor Xa with factor Va activates factor II (prothrombin) to factor IIa (thrombin). Factor IIa cleaves fibrinogen to fibrin monomers, activates platelets, factor XIII to factor XIIIa which cross links fibrin monomers to insoluble hemostatic thrombus.

Defects are related to coagulation factor deficiencies that can be congenital or acquired.

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