Biochemistry

communication between them is maintained. In addition, water is an environment where all chemical reactions associated with the life of the body occur. Water plays an important mechanical role, contributing to the sliding of rubbing surfaces (joints, ligaments, etc.). Due to the evaporation of water from the surface of the skin, humans and warm-blooded animals maintain a constant body temperature with increased heat in the body or at high ambient temperatures. Water is the basis of all fluids in the body: blood, lymph, urine, juices of the digestive apparatus, cerebrospinal fluid, etc. Therefore, all living organisms, as a rule, are not able to tolerate dehydration. Man and animals die from a lack of water much sooner, a ches from a lack of food. If a person can survive complete starvation for 30 days or more, then death occurs without water in a few days. In the human body, the water content is 2/3 of body weight and varies with age. In the body of men, on average, 60% of water is contained, while in women - 50%. The water level in different tissues varies. Connective and bone tissues contain relatively little water, and blood, nerve tissue, muscles, and liver - much less. The amount of water in the body also depends on the fat content: the more fat, the less water. All water in the body can be divided into intracellular or intracellular (~72%) and extracellular or extracellular (~28%). Blood, lymph and intercellular fluid of the whole body form a single phase. The composition of lymph and intercellular fluid approximately corresponds to the composition of blood plasma. The liquid medium of cells of various body tissues has approximately the same composition and is defined as intracellular fluid. Intracellular fluid contains on average about 35-45% of water in relation to body weight, extracellular - 15%. These fluids also differ in the composition of electrolytes. In the extracellular fluid, sodium, chlorine and bicarbonate ions predominate; in the intracellular - potassium ions, as well as proteins and phosphoric esters. The state of water in the body. In organs, tissues and cells, water is in the form of free, hydration, and immobilized. Free water is the basis of many biological fluids: blood, lymph, digestive juices, cerebrospinal fluid. It is involved in the delivery of nutrients and the removal of metabolic products from organs, tissues and cells. Part of the water is in a bound state, participating in the formation of hydration shells. This is the so-called hydration water. It forms hydration shells around the molecules of proteins, nucleic acids and inorganic ions. Hydration 21