Blood performs three main functions:
Supplying oxygen and nutrients to body tissues and removing waste products.
Protecting the body from diseases by producing antibodies and protecting against infection.
Maintaining a constant body temperature by circulating blood throughout the body.
Bleeding causes several reactions in the body. The brain, heart and kidneys try to instantly compensate for blood loss to maintain the flow of oxygenated blood to vital organs. The blood at the wound site begins to clot. Coagulation is the process of blood thickening, which is aimed at blocking a damaged vessel and stopping bleeding. The body also begins to produce more red blood cells, which helps increase the supply of oxygen to the cells. Excess fluid in the body, which would normally be eliminated from the body, is reintroduced into the bloodstream in order to maintain a constant circulating blood volume. The life of the victim is threatened by severe bleeding, which leads to a decrease in the volume of circulating blood to a critical level. As a result, vital organs do not receive enough oxygen.