Аннотация
In the review article the basic structures and peculiarities of water and salt metabolism of kidneys, the normal development of the growing organism, the impact of the environment and habitat as well as the effect of the physical and chemical composition of daily drinking water. Kidneys ensuring the release of up to 80 % of water-soluble products formed in the process of metabolism and exogenous substances, are involved in regulating the stability of the concentration of osmotically active substances (osmoregulation), the volume of body fluids (volumetric regulation), the concentration of individual ions (ion regulation) and acid-base equilibrium, being thus the main homeostatic organ. Along with this, the metabolic role of kidneys is shown in the metabolism of proteins, fats and carbohydrates, as well as their importance in the synthesis of biologically active substances and hormones affecting erythropoiesis, blood pressure regulation, calcium metabolism, etc. Only one kidney function will be discussed — its participation in the regulation of water-salt homeostasis in children of different ages. There are many factors that prevent this complicated process from developing normally in young children, particularly in hygienic and sanitary levels. In this regard, currently the infectious diseases of the urogenital system are especially prevalent in young children.