
thumb|right|Composition of a fresh thrombus at microscopy, [[HE stain, showing nuclear debris in a background of fibrin and red blood cells.]] thumb|right|Micrograph showing fibrin (dark pink amorphous material) in a blocked [[vein surrounded by extravasated red blood cells (right of image). An artery (left of image) and the amnion (far left of image) is also seen. Placenta in a case of fetal thrombotic vasculopathy. H&E stain.]]
thumb|right|Composition of a fresh thrombus at microscopy, [[HE stain, showing nuclear debris in a background of fibrin and red blood cells.]] thumb|right|Micrograph showing fibrin (dark pink amorphous material) in a blocked [[vein surrounded by extravasated red blood cells (right of image). An artery (left of image) and the amnion (far left of image) is also seen. Placenta in a case of fetal thrombotic vasculopathy. H&E stain.]]
Fibrin (also called Factor Ia) is a fibrous, non-globular protein involved in the clotting of blood. It is formed by the action of the protease thrombin on fibrinogen, which causes it to polymerize. The polymerized fibrin, together with platelets, forms a hemostatic plug or clot over a wound site.
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).