In doing so, it has replaced the previously named extrinsic pathway in order to eliminate ambiguity.

The resulting complex provides a catalytic event that is responsible for initiation of the coagulation protease cascades by specific limited proteolysis.

Unlike the other cofactors of these protease cascades, which circulate as nonfunctional precursors, this factor is a potent initiator that is fully functional when expressed on cell surfaces.

Binding of VIIa to TF has also been found to start signaling processes inside the cell.

This can change when the blood vessel is damaged by, for example, physical injury or rupture of atherosclerotic plaques.

Exposure of TF-expressing cells during injury allows the complex formation of TF with factor VII.

Endothelial cells do not express TF except when they are exposed to inflammatory molecules such as tumor necrosis factor-alpha (TNF-alpha).

When manipulated in the laboratory, a derivative could be created called partial thromboplastin, which was used to measure the intrinsic pathway.