Physiology · Blood

Coagulation cascade and anticoagulant mechanisms

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Definition

  • Blood coagulation is activation of a cascade of normally inactive plasma clotting factors, occurring simultaneously with platelet activation, that converts fibrinogen to a stable fibrin clot.
  • Coagulation proceeds in three stages:
    1. Prothrombin activator (factor Xa) formation.
    2. Thrombin formation from prothrombin.
    3. Fibrin formation from fibrinogen.

Clotting Factors

Clotting factors (I to XIII, factor VI absent)

Factor

I

Name
Fibrinogen

II

Name
Prothrombin

III

Name
Tissue thromboplastin

IV

Name
Calcium ion

V

Name
Proaccelerin

VII

Name
Proconvertin

VIII

Name
Antihemophilic factor (AHG)

IX

Name
Christmas factor (antihemophilic factor B)

X

Name
Stuart Prower factor

XI

Name
Plasma thromboplastin antecedent (antihemophilic factor C)

XII

Name
Hageman factor (contact factor)

XIII

Name
Fibrin stabilizing factor (Laki-Lorand factor)