Third, blood has the functions of coagulation, hemostasis and anticoagulation. People accidentally cut the skin of their fingers, and blood will flow out immediately, but after we press the wound hard, the small wound will soon stop bleeding. Why? This is mainly due to the coagulation system in the blood. Blood also has an anticoagulant system. When there is thrombosis, the anticoagulant system is activated to dissolve some small thrombus, mainly relying on the role of fibrinolytic enzyme. Under normal circumstances, the coagulation system and anticoagulant system are in dynamic balance, so there will be no thrombosis and bleeding in human blood. Fourthly, blood is a big buffer system, which keeps the pH value of human body tissue fluid constant within a certain range, thus giving full play to the functions of various tissues and cells. Tissue cells have been producing waste. These substances are acidic and alkaline, and blood is a big buffer pool, which can neutralize these acids or alkalis.
Fifth, blood is a thermoregulator, which can keep people's body temperature constant. The temperature regulation of human body is dominated by nerve center, but its function is mainly completed by blood. When the external environment becomes cold, the blood flowing to human skin decreases and the heat dissipation decreases; When the outside temperature rises, the blood flowing to the skin increases, the circulation is accelerated, and the heat dissipation is increased, thus keeping the body temperature constant.
Sixth, blood is the medium of endocrine organs and target organs. Hormones secreted by endocrine organs are transmitted to target organs through blood, and then play a role. For example, thyroid cells secrete thyroxine and release it into the blood, which is transmitted to the whole body.