Which blood protein initiates blood coagulation?? Prothrombin or Fibrinogen..

I think it's thromboplastin.

-1

Introduction on fibrin blood clotting:

Fibrin is a non globular fibrous protein that is involved in the clotting of blood. It is also called as Factor Ia. Fibrin is a fibrillar protein which polymerises to form a mesh resulting in clot over a wound. Apart from blood clotting, fibrin is also known to be involved in a number of biological processes such as signal transduction, platelet activation, polymerization of proteins.

Structure of fibrin and its physiology:

A double-d fragment structure of human fibrin is made up of single alpha helix and a single beta helix. The ligands that are bound to these helices structurally at their chemical level are calcium ions, α-D mannose and D-glucosamine. Fibrin is generally seen glycosylated in animal sources.

Fibrin and its Involvement in Blood Clotting:

The conversion of highly soluble plasma protein, the fibrinogen to a stringy protein, the fibrin is the major mechanism involved in clot formation. The series of steps involved in blood clotting are:

Prothrombin activator is synthesized. Interaction of prothrombin activator with calcium ions causes prothrombin which is a α-globulin class of protein to be converted to thrombin.
Thrombin, which acts as an enzyme triggers a series of chemical reactions in fibrinogen that helps in end to end molecule binding in long threads resulting in fibrin structures. These fibrin structures adhere to the damaged portion of the blood vessel forming a mesh trapping blood cells and platelets. This sticky mass which is resulted called a clot seals the punctured blood vessels thus preventing further blood loss.

Fibrin and its uses:

Fibrin can interact with several different cell types that include endothelial cells, fibroblasts, smooth muscle cells, fibroblasts, leucocytes. Fibrin is known to bind and accumulate the cells that are required for the inflammatory response and the cells responsible for tissue repair at the damaged area.

Fibrin Blood Clotting:conclusion

Fibrin which is a fibrous protein is produced from fibrinogen during the clotting process as fibrin strands which form a mesh. This resulting mesh traps the platelets and blood vessels preventing any further loss of blood from the damaged site. The punctured blood vessels are sealed by the clot that is formed as a result of the mesh formed by the adhering of the fibrin structures.