What Is the Coagulation System?

Blood coagulation is a series of complex chemical chain reaction processes. The system composed of multiple substances involved in each chain reaction is called the coagulation system.

Coagulation system

Its chemical nature, except

Blood coagulation can be roughly divided into three stages (picture):

In the first stage, the formation of prothrombin activators is divided into endogenous coagulation system and exogenous coagulation system according to their formation pathways. Exogenous coagulation system, also known as tissue system coagulation, is the release of coagulation factor III from injured tissues, entering the plasma, and forming a complex with factor and Ca, which can catalyze factor X into activating factor X (Xa). Xa, V, Ca and platelet phospholipids together form a prothrombin activator. Endogenous coagulation system, also known as blood system coagulation, means that all substances involved in coagulation are present in the blood. In atherosclerosis and vasculitis

Diagram of the coagulation process

Under normal circumstances, the intima of the blood vessel is damaged (the blood does not flow out of the blood vessel, but the blood vessel coagulates to form a thrombus). The factor in the plasma is activated by contact with the collagen fibers exposed by the damaged blood vessel. With the participation, certain coagulation factors (, , , X, V) are successively activated, and together form a prothrombin activator. Since then, there has been no difference between exogenous and endogenous coagulation processes. Because bleeding after tissue damage must be accompanied by vascular damage, the coagulation process of blood flowing out of the body involves both the exogenous coagulation system and the endogenous coagulation system.

In the second stage, with the participation of Ca, the prothrombin activator catalyzes the conversion of prothrombin (factor II) to active thrombin (IIa).

In the third stage, under the catalysis of thrombin, Ca, and factor XIII, the soluble fibrinogen in the plasma was changed to insoluble fibrin. Fibrin is filament-like, criss-cross, gathering a large number of blood cells, forming a gel-like blood clot, the time required from the time the blood flows out of the body to the appearance of filament-like fibrin. When clotting is called, it is normally 2 8 minutes (slide method). ^[1]