Fibrin is a fibrous protein in blood plasma. Formed from fibrinogen under the action of thrombin in the clotting of blood (see blood Clotting). Fibrin is the structural basis of a blood clot. Fibrin is dissolved under the action of the enzyme fibrinolizina. The high content of fibrinogen in the blood plasma (2-3 g/l) provides the possibility of formation of fibrin in bleeding. The conversion of fibrinogen to fibrin in the bloodstream can serve as the basis of thrombosis and embolism. In reticuloendothelial system can occur enveloping fibrin alien particles, trapped in the body. Made from fibrin plate, "clove", threads are used in surgery as a natural materials with a certain term of resorption.