An Introduction to the Fundamentals of Coagulation: Overview of Secondary Hemostasis

Secondary Hemostasis – The Extrinsic Pathway

  • It should be noted that this pathway is sometimes referred to as the Tissue Factor Pathway.

  • Once a vessel has been breached, tissue factor is exposed to circulating factor VII, and the two substances bind to form a complex.

  • The newly formed tissue factor/factor VII complex is thought to be the primary physiological stimulus for blood coagulation.

  • In other words, more hemostatic activities are initiated by the extrinsic pathway than the intrinsic.

  • This complex leads to the activation of factor VII (factor VIIa) which is now ready to catalyze the conversion of factor X to factor Xa as part of the common pathway.


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