The exchange of water and mineral salts
Water – the most common substance in our body. Adult human consists of water by about 65%, and the human embryo contains about 90% water. The day the human body loses about 2.0-2.5 liters of water. The same amount he receives in the amount with the drink (1.0 L) and food (1.0 L). Water and dissolved mineral salts are absorbed throughout the gastrointestinal tract, but most of all – in the villi of the small intestine. Dehydration leads to rapid death, and without water a person can not live more than 5-6 days, whereas without food, he can do more than 50 days. Water is essential in the body as a medium in which the tested all chemical reactions. It is a vehicle, transferring solutions of substances through the body (blood plasma, lymph, intercellular fluid). Water is needed to maintain a constant body temperature. Water is removed from the body through the kidneys (about 1 liter per day), skin (0.8 liters per day), with the pairs of air through the lungs (0.5 liters per day), with the feces (0.15 L per day).
Of the inorganic substances besides water body needs a continuous supply of mineral salts. Although they make up less than 4% of body weight, a set of very diverse. At night in the human body must be supplied with food and drink for at least 8 g sodium chloride 5 g, 3 g of potassium, 1 g of calcium and 2 g of phosphorus, 0.2 g of iron. These substances are called macronutrients. A trace elements necessary for the person in very small doses – parts milligrams, but normal life is impossible without them. For micronutrients include copper, iodine, zinc, fluoride, magnesium and many other substances.
Functions of mineral salts in humans are varied. Thus, salts of calcium, phosphorus and magnesium are part of bone; potassium, sodium and chlorine are required for excitation of nerve and muscle cells; Calcium is needed for normal muscle contraction and blood clotting; fluorine is a part of dentin and enamel; Iron is a component of hemoglobin; phosphates incorporated into the DNA, RNA, ATP, bones; Copper contained in the composition of a number of enzymes that provide the nervous system, blood formation; Iodine is a part of thyroid hormone; Cobalt is part of vitamin B12.
Allocation
Allocation – a process of elimination of the final metabolic products (metabolites) which can not be further used by the body for its needs. The value allocation is to maintain a constant internal environment. The decay products of various substances produced in the course of various metabolic reactions, enter the blood and excreted from the body in several ways. The main organs are kidneys isolation through which excess water is removed, nitrogen-containing decomposition products of proteins, some salt and many other substances. Thus, the kidney to maintain a constant ratio of the level of water and salts in the body. Through the lungs of a human body is removed CO2 small amount of water vapor, some of the volatiles. The sweat glands secrete water through the skin, urea, ammonia, salt. Through the intestines from the body with feces removed salt toxic heavy metals, the reaction products of bile pigments (bilirubin and biliverdin).
(2 votes, average: 4.50 out of 5)