This site is intended for healthcare professionals

Go to /sign-in page

You can view 5 more pages before signing in

Common pathway of blood coagulation

Last reviewed dd mmm yyyy. Last edited dd mmm yyyy

Authoring team

The common pathway of coagulation starts with the conversion of factor X to Xa; in the intrinsic pathway this is caused by factor IXa, in the extrinsic pathway this is caused by tissue factor. Co-factors are required for both limbs.

Factor Xa requires its own co-factors for activity. These include calcium ions, circulating factor V and the negatively-charged platelet surface for localisation. It is then able to cleave prothrombin (factor II) to thrombin (factor IIa).

Thrombin is an enzyme with four key functions:

  • removal of small fibrinopeptides from the large fibrinogen precursor; this favours the polymerization of fibrinogen into strands of fibrin
  • activation of factor XIII to XIIIa; XIIIa is the fibrin-stabilizing factor, which in the presence of calcium ions, interlinks fibrin strands
  • activation of platelets
  • activation of protein C, an antithrombotic plasma enzyme

Therefore, a network of insoluble fibrin is formed which is localised to the site of injury and traps oncoming blood cells.


Related pages

Create an account to add page annotations

Annotations allow you to add information to this page that would be handy to have on hand during a consultation. E.g. a website or number. This information will always show when you visit this page.