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Factor VII

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Definition

noun

A blood clotting factor of the extrinsic pathway of the blood coagulation cascade that is activated into factor VIIa when bound to tissue factor


Supplement

Coagulation, the process of clot formation, involves platelet and blood clotting factors. In humans, the coagulation mechanism is comprised of two processes, i.e. the primary hemostasis and the secondary hemostasis. The latter entails two pathways: (1) intrinsic pathway (contact activation pathway) and (2) extrinsic pathway (tissue factor pathway). Both pathways lead to the formation of fibrin.

Factor VII is a blood clotting factor that is produced from the liver. The gene that codes it is on chromosome 13 (13q34). Its production is activated by the tissue factor. The tissue factor is an integral membrane glycoprotein encoded by the F3 gene. It is expressed on the cell surface when there is an injury in blood vessels. It is produced by sub-endothelial cells and cells (e.g. fibroblasts) that surround blood vessels. It is also expressed on the surface of endothelial cells and monocytes when they become exposed to inflammatory molecules (e.g. TNF-alpha). The tissue factor is involved in the initiation of thrombin formation. It has an affinity for the clotting factor VII. Exposed tissue factor due to injured blood vessel binds to factor VII. When bound, factor VII is activated into factor VIIa by proteases (e.g. thrombin). The complex formed stimulates the initiation of the coagulation protease cascades, particularly catalyzing the conversion of clotting factor X (Stuart factor) and clotting factor IX (Christmas factor) into active proteases, i.e. factor Xa and IXa, respectively.

Factor VII deficiency is the associated genetic disorder with this factor.


Also called:

  • (blood-) coagulation factor VII
  • proconvertin
  • clotting factor VII
  • convertin
  • cothromboplastin
  • serum accelerator
  • serum acceleratorglobulin
  • serum prothrombin conversion accelerator
  • activated blood coagulation factor VII

See also: