During the life of the body it occurs, on the one hand, the destruction (dissimilation) substances included in the composition of tissues and cells, on the other — a constant renewal, restoration and rebuilding previously destroyed substances due to the nutrients supplied from food (assimilation) . These two processes that make up metabolism are closely linked, are in interdependence and a state of dynamic equilibrium, with the result that cells and tissues retain their relatively constant composition. With the destruction of substances in the body the oxidation of complex organic substances in the composition and allocation of this energy needed for muscle work the body, keeping at a certain level of body temperature and other vital processes. The same energy, released during the destruction, is necessary to ensure the processes of reconstruction, during which there is a formation of simple organic compounds complex, with a large reserve of energy. This process is called metabolism in the body. It is the basis of all physiological functions of the body, which include breathing, blood circulation, digestion, nervous activity, etc.All these manifestations of the body are under the regulatory influence of the nervous system.