Answer to Question #300459 in Human Anatomy and Physiology for Matt

Question

Which factor is found in tissues and not in the blood?

Answer 1

Tissue factor, also called platelet tissue factor, factor III, or CD142, is a protein encoded by the F3 gene, present in subendothelial tissue and leukocytes.Tissue factor (TF) is an integral membrane protein that is the essential cofactor component of the TF-factor VIIa complex enzyme. TF is expressed in the vascular adventitia, in astroglial cells, in organ capsules and is found in the central nervous system, lungs, and placenta at relatively high concentrations.Tissue factor (TF) expression by nonvascular cells plays an essential role in hemostasis by activating blood coagulation. In contrast, TF expression by vascular cells induces intravascular thrombosis. Finally, TF-dependent assembly of coagulation proteases on vascular cells activates protease activated receptors, which contributes to inflammation, angiogenesis, and metastasis.