ChapterIV.13.

Mineral exchange

Mineral exchange is a set of suction processes, distribution, assimilation and separation of mineral substances in the body mainly in the form of inorganic compounds.

In total, over 70 elements of the Table D.I. are found in the body. Mendeleev, 47 of them are constantly being called biogenic. Mineral substances play an important role in maintaining acid-base equilibrium, osmotic pressure, blood coagulation system, regulation of numerous enzyme systems, and so on, i.e. are crucial in creating and maintaining homeostasis.

On quantitative content in the body they are divided into macroelementsif there are more than 0.01% of the body weight (K, CA, MG, Na, P, CL) and trace elements (Mn, Zn, Cr, Cu, Fe, CO, Al, SE). The bulk of the body of the body is chloride, phosphorous and carbonic salts of sodium, calcium, potassium, magnesium. Salts in body fluids are in partially or completely dissociated form, so mineral substances are present in the form of ions - cations and anions.

Mineral functions:

1) plastic (calcium, phosphorus, magnesium);

2) maintaining osmotic pressure (potassium, sodium, chlorine);

3) maintaining the bufferiness of biological fluids (phosphorus, potassium, sodium);

4) maintaining colloidal properties of tissues (all elements);

5) detoxification (iron in the composition of cytochrome p-450, sulfur in glutathione);

6) carrying out a nervous impulse (sodium, potassium);

7) participation in enzymatic catalysis as a cofactor or inhibitor;

8) Participation in hormonal regulation (iodine, zinc and cobalt are included in the hormones).

Intermediate and finite exchange of minerals

Mineral substances come to the body in free or related form. Ions are already absorbed in the stomach, the main part of the mineral substances is in the intestine by active transport with the participation of proteins - carriers. From the gastrointestinal tract is entered into blood and lymph, where they are associated with specific transport proteins. Mineral substances are mainly distinguished in the form of salts and ions.

With urine: sodium, potassium, calcium, magnesium, chlorine, cobalt, iodine, bromine, fluorine.

With feces: Iron, calcium, copper, zinc, manganese, molybdenum, and heavy metals.

Characteristics of individual elements

Sodium - the main cation of the extracellular department. Is 0.08% of body weight. Plays a major role in maintaining osmotic pressure. In the absence or restriction in the flow of sodium into the body, its allocation with urine almost completely stops. It is absorbed in the upper division of the small intestine with the participation of carrier proteins and requires ATP costs. The daily need varies on the dependence of the all-salt-salt supply of the body. Deposited in the skin and muscles. Sodium intestinal loss occurs when diarrhea.

1) participates in the emergence and maintenance of electrochemical potential on plasma membranes of cells;

2) regulates the state of the water-salt metabolism;

3) participates in the regulation of the work of enzymes;

4) Component K + - Na + pump.

Chlorine - the most important anion of the extracellular space. Is 0.06% of body weight. Most of it is contained in gastric juice. Participates in maintaining osmotic equilibrium. Activates amylase and peptidases. It is absorbed in the upper intestinal departments, it is highlighted mainly with urine. The concentration of chlorine and sodium usually change in parallel.

Potassium - Makes 0.25% by body weight. In the extracellular space, only 2% of the total amount is contained, and the rest is in cells where is associated with carbohydrate compounds. Absorbed throughout the gastrointestinal tract. Part of potassium is postponed in the liver and skin, and the rest enters the overall blood flow. The exchange takes place very quickly in the muscles, intestines, kidneys and liver. In red blood cells and nerve cells, a slower potassium exchange. Plays a leading role in the emergence and conduct of a nervous impulse. We are necessary for protein synthesis (1g protein - 20 mg of potassium ions), ATP, glycogen, takes part in the formation of resting potential. It is highlighted mainly with urine and less with the feces.

Calcium - extracellular cation. It is 1.9% of body weight. The content rises in the period of growth or pregnancy. Functioning as an integral part of supporting tissues or membranes, participates in the conduct of a nervous impulse and the initiation of muscle contraction, is one of the factors of hemocoagulation. Provides the integrity of membranes (affects permeability), since it helps the tight packaging of membrane proteins. Calcium is limited to maintaining osmotic equilibrium. Along with insulin activates the penetration of glucose into the cells. Suks in the upper intestinal department. The degree of assimilation depends on the pH of the medium (calcium salts in an acidic environment are insoluble). Fats and phosphates prevent calcium suction. For complete assimilation from the intestine, it is necessary to have an active form of vitamin d 3

Most calcium is contained in bone tissue (99%) as part of carbonatite microcrystals 2 (PO 4) 2· Saso 3 and hydroxylapatitis 3as 2 (PO 4) 2· Saon. Common blood calcium includes three fractions: white-knitted, ionized and non-ionossed (which is located in citrate, phosphate and sulfate).

Magnesium - is 0.05% of body weight. In cells it is contained 10 times more than in extracellular fluid. Much magnesium in muscle and bone tissue, also in nervous and hepatic. Forms complexes with ATP, citrate, near the proteins.

1) is part of almost 300 enzymes;

2) magnesia complexes with phospholipids reduce the fluidity of cell membranes;

3) participates in maintaining normal body temperature;

4) participates in the work of the neuromuscular apparatus.

Inorganic phosphorus - Contained mainly in bone tissue. It is 1% of body weight. In the blood plasma in physiological pH, phosphorus is 80% represented by a bivalent and 20% monovalent phosphoric acid anion. Phosphorus is part of coenzymes, nucleic acids, phosphoproproteins, phospholipids. Together with Calcium, phosphorus forms apatites - the basis of bone tissue.

Copper It is part of many enzymes and biologically active metalloproteins. Participates in the synthesis of collagen and elastin. Is a component cytochrome S. Electropline circuit.

Sulfur - is 0.08%. Enters the body in the associated form in the composition of AK and sulfate ions. Included in the composition of bile acids and hormones. As part glutathione Participates in biotransformation of poisons.

Iron It is a member of iron-containing proteins and hemoglobin, cytochromes, peroxidases.

Zinc - It is a cofactor of a number of enzymes.

Cobalt It is part of the vitamin B 12.

Water and electrolyte exchange

Water and electrolyte exchange is a combination of proceeds, suction, distribution and isolation from the body of water and electrolytes. It ensures the constancy of the ionic composition, the acid-base equilibrium and the volume of fluids of the body of the body. Water plays a leading role in it.

Water functions:

1) internal environment of the body;

2) structural;

3) suction and transport substances;

4) participation in biochemical reactions (hydrolysis, dissociation, hydration, dehydration);

5) final exchange product;

6) allocation with the participation of kidney final exchange products.

Water that comes by an alimentary (with food) is called an exogenous, and the biochemical transformations formed as a product - endogenous.

All transformations of substances in the body are performed in the aquatic environment. Water dissolves foodstuffs that entered the body. Together with minerals, it takes part in the construction of cells and in many exchange reactions.

Water is involved in the regulation of body temperature; evaporating, cools the body, preventing it from overheating; Transport solutions.

Water and mineral salts create mainly the inner medium of the body, being the main component of the blood plasma, lymph and tissue fluid. They are involved in maintaining the osmotic pressure and reaction of blood plasma and tissue fluid. Some salts dissolved in the liquid blood are involved in the transfer of gases by blood.

Water and mineral salts are part of the digestive juices, which largely determines their value for digestion processes. And although neither water nor mineral salts are sources of energy in the body, their admission to the body and the elimination of from there are a prerequisite for its normal activity.

Loss of water by the body leads to very difficult violations. For example, when disordering digestion in infants, the most dangerous is the dehydration of the body, which entails convulsions, loss of consciousness, etc. It is a sharp dehydration of the body due to the loss of a fluid that causes such a severe course of such an infectious disease as cholera. The deprivation of water for several days is mortally for a person.

Water exchange

The replenishment of the body with water occurs constantly due to the absorption of it from the digestive tract. A person needs a day 2-2.5 liters of water with normal food mode and normal ambient temperature. This amount of water comes from the following sources: a) water consumed when drinking (about 1 l); b) water contained in food (about 1 l); c) water that is formed in the body when exchanging proteins, fats and carbohydrates (300-350 ml).

The main organs removing water from the body, kidneys, sweat glands, light and intestines. The kidneys per day from the body remove 1.2-1.5 liters of water as part of urine. Sweet glands through the skin in the form of sweat are removed 500-700 ml of water per day. At normal temperature and humidity of air on 1 cm2 of the skin, about 1 mg of water is distinguished every 10 min. In the deserts of the Arabian Peninsula, however, a person loses a daily from then about 10 liters of water. With intensive work in the form of Pot, a lot of fluid is also highlighted: for example, in two half of the intense football match, a soccer player loses about 4 liters of water.

Light in the form of water vapor remove 350 ml of water. This amount increases sharply in the deepening and efficiency of breathing, and 700-800 ml of water can be distinguished during the day.

Through the intestine with the feces is excreted 100-150 ml of water. When the intestinal activity disorder, a large amount of water may be excluded (with diarrhea), which can lead to water tolerance. For the normal activity of the body, it is important that water flow fully covered its consumption.

The ratio of the amount of water consumed to the amount of dedicated is water balance.

If water from the body is excreted more than entering it, the feeling arises thirst. As a result, the thirst person drinks water until the restoration of a normal water balance is restored.

Salley exchange

In the exclusion of the food diet of animal minerals, heavy disorders in the body and even death occur. With the presence of mineral substances, the phenomenon of excitability is connected - one of the main properties of the living. The growth and development of bones, nerve elements, muscles depend on the content of mineral substances; They determine the blood reaction (pH), contribute to the normal activity of the heart and nervous system, are used to form hemoglobin (iron), gastric acid hydrochloric acid (chlorine).

Mineral salts create a certain osmotic pressure for the livelihoods of cells.

With mixed nutrition, an adult receives all the mineral substances you need in sufficient quantity. Only the cook salt is added to the food of a person when it is culinary processing. A growing children's body especially needs to be addressed to many minerals.

The body constantly loses some of the mineral salts in the composition of urine, sweat and feces. Therefore, mineral salts, as well as water, should constantly enter the body. The content of individual elements in the human body is not the same (Table 13).

Regulation of water and salt metabolism

The constancy of the osmotic pressure of the inner medium of the body, determined by the content of water and salts, is regulated by the body.

With a lack of water in the body, the osmotic pressure of the tissue fluid increases. This leads to an irritation of special receptors located in the tissues - osoryceptor. The pulses from them on special nerves are sent to the brain to the center of regulating the water-salt exchange. From there, the excitation is sent to the gland of the internal secretion - the pituitary gland, which highlights a special hormone into the blood, causing the urinary delay. Reducing the separation of water with urine restores disturbed equilibrium.

This example clearly shows the interaction of nerve and humoral mechanisms for the regulation of physiological functions. The reflex begins nervous from the Osoricceptors, and then the humoral mechanism is turned on - the admission to the blood of a special hormone.

The regulation of the water-salt exchange controls all the ways of transporting water in the body: the release of it with urine, then through the lungs, redistribution between body bodies, suction from the digestive tract, secretion, as well as water consumption. Some parts of the intermediate brain are particularly important in this regard. If you enter the animal to enter the electrodes in these sites, and then through them to start irritating the brain by electric shock, then the animals begin to eat greedily drinking water. In this case, the amount of water drilled may exceed 40% of body weight. As a result, signs of water poisoning appear associated with a decrease in the osmotic pressure of blood plasma and tissue fluid. In natural conditions, these intermediate centers are under the controlling influence of the bark of large hemispheres of the brain.

The mechanism of the regulation of the water balance is very important in practical life. In cases where water has to save, it is not necessary to drink it by a volley, but necessarily very small sips. You will feel that we got drunk, although the water drank a little. Knowledge of the peculiarities of the regulation of water-salt metabolism is important in one case. In hot weather, I usually really want to drink, and no matter how much water you drink, you want to drink anyway. But it is worth a consciously to suffer a little, despite the feeling of thirst, and she passes. That is why it is not necessary to drink a lot in the heat, in the campaign, etc. The correct tactics here is: knowing that a difficult hike or a long stay in the sun is to be better, it is better to drink water in advance "about stock", at the moment when you still do not want to drink . In this case, then it does not arise such a strong feeling of thirst, as if you started drinking at the heat.

Two more practical councils. Before sending to the campaign, you have to drink mineral or salted water or eat a little moderately salty food - cheese, salted cheese, etc. - and well drink it with water. The fact is that with then many salts are lost, and this leads to an increase in fatigue, muscular weakness, etc. It is also necessary to know that there is often a "false thirst" in the heat: I don't want to drink because there is little liquid in the body, And due to the drying of the oral mucosa. In this case, it is enough just to rinse the mouth with water.

Mineral exchange is a set of suction processes, assimilation, distribution, transformations and isolation from the organism of those substances that are in it mainly in the form of inorganic compounds. Mineral substances in the composition of the biological fluid create an internal environment of the body with constant physicochemical properties, which ensures the normal functioning of cells and tissues. The determination of the content and concentrations of a number of mineral substances in body fluids is important diagnostic tests in many diseases. In some cases, the impairment of mineral metabolism is the cause of the disease, in others - only the symptoms of the disease, but any disease to one degree or another is accompanied by a violation of water-mineral exchange.

In terms of quantity, the main part of the body's mineral compounds is chloride, phosphate acid and carbonic salts of sodium, potassium, calcium and magnesium. In addition, the organism contains compounds of iron, manganese, zinc, copper, cobalt, iodine, and a number of other trace elements.

Mineral salts in the aqueous media of the body are partially or completely dissolved and exist as ions. Minerals can also be in the form of insoluble compounds. In bone and cartilage tissues, 99% of the entire calcium of the body are concentrated, 87% phosphorus, 50% magnesium. Mineral substances are part of many organic compounds, such as proteins. The mineral composition of some adult tissues is given in the table.

Mineral composition of some adult tissues (for 1 kg of fresh tissue weight)

Name of fabric	Sodium	Potassium	Calcium	Magnesium	Chlorine	Phosphorus (moths)
Name of fabric	milliqivalents
Skin	79,3	23,7	9,5	3,1	71,4	14,0
Brain	55,2	84,6	4,0	11,4	40,5	100,0
Kidney	82,0	45,0	7,0	8,6	67,8	57,0
Liver	45,6	55,0	3,1	16,4	41,3	93,0
Cardiac muscle	57,8	64,0	3,8	13,2	45,6	49,0
Skeletal muscle	36,3	100,0	2,6	16,7	22,1	58,8

The main source of mineral substances for the body are food. The largest amount of mineral salts is contained in meat, milk, black bread, legumes and vegetables.

From the gastrointestinal tract, minerals enroll in blood and lymph. The ions of some metals (CA, FE, CU, CO, Zn) are already in the process or after suction are connected with specific proteins.

An excess of mineral substances in a person is excluded mainly through the kidneys (ions Na, K, CL, I), as well as through the intestines (Ions Ca, Fe, Cu, etc.). The complete elimination of a significant excess of salts, which most often occurs during the excessive consumption of the cooking salt, occurs only in the absence of restrictions in drinking. This is due to the fact that the urine of a person contains no more than 2% of the salts (the maximum concentration with which the kidneys can work).

Water-salt exchange

The water-salt exchange is part of the mineral exchange, it is a combination of proceeds in the body of water and salts, mainly NaCl, the distribution of them in the internal environment and removal from the body. Normal water-salt exchange provides constant blood volume and other organism fluids, osmotic pressure and acid-alkaline equilibrium. The main mineral substance, due to which the body regulates the osmotic pressure, is sodium, about 95% of the osmotic pressure plasma pressure is adjusted using this mineral substance.

The water-salt exchange is a combination of processes of water and salts (electrolytes) into the body, the distribution of them in the inner medium and excreting from the body. The regulation systems of water-salt metabolism ensure the constancy of the total concentration of dissolved particles, ionic composition and acid-alkaline equilibrium, as well as the volume and qualitative composition of the body fluids.

The human body consists on average by 65% \u200b\u200bof water (from 60 to 70% of body weight), which is located in three liquid phases - intracellular, extracellular and transcellular. The greatest amount of water (40 - 45%) is inside the cells. Extracellular fluid includes (as a percentage of body weight) blood plasma (5%), intercellular fluid (16%) and lymph (2%). Translationular liquid (1 - 3%) is isolated from vessels with a layer of epithelium and in its composition is close to extracellular. This is a spinal and intraocular liquid, as well as the liquid of the abdominal cavity, pleura, pericardium, articular bags and the gastrointestinal tract.

Water and electrolyte balancers in humans are calculated on the daily consumption and isolating water and electrolytes from the body. Water enters the body in the form of a drink - approximately 1.2 liters and with food - approximately 1 liter. About 0.3 liters water is formed during the metabolism process (of 100 grams of fats, 100 grams of carbohydrates and 100 grams of proteins are formed 107, 55 and 41 ml of water, respectively). The daily need of an adult in electrolytes is approximately: sodium - 215, potassium - 75, calcium - 60, magnesium - 35, chlorine - 215, phosphate - 105 mg-eq per day. These substances are absorbed in the gastrointestinal tract and enter blood. Temporarily they can be deposited in the liver. Excess water and electrolytes are excreted by kidneys, light, intestines and leather. On average, the duration of the separation of water with urine is 1.0 - 1.4 liters, with a fee - 0.2, with skin and from then 0.5, light - 0.4 liters.

The water entered into the body is distributed between different liquid phases, depending on the concentration of osmotically active substances in them. The direction of water movement depends on the osmotic gradient and is determined by the state of the cytoplasmic membrane. The distribution of water between the cell and the intercellular fluid is influenced by the overall osmotic pressure of the extracellular fluid, and its effective osmotic pressure, which is determined by the concentration in the liquid substances poorly passing through the cell membrane.

In humans and animals, one of the main constants is pH of the blood, supported at about 7.36. In the blood there is a series of buffer systems - bicarbonate, phosphate, plasma proteins, as well as hemoglobin, - supporting blood pH at a constant level. But in the main pH of blood plasma depends on the partial pressure of carbon dioxide and the concentration of NSO3.

Separate organs and tissues of animal and humans differ significantly in the content of water and electrolytes.

Water content in various organs and adult tissues for the weight of the fabric

The most important importance for the activities of cells of all organs and systems has the maintenance of ion asymmetry between intracellular and extracellular fluid. In the blood and other extracellular fluids, the concentration of sodium ions, chlorine, bicarbonate; In cells, the main electrolytes are potassium, magnesium and organic phosphates.

Biological fluids secreted by various glands differ in ionic composition from blood plasma. Milk isoosmotic with respect to blood, but in it lower than in plasma, sodium concentration and above calcium, potassium, phosphates. Sweat has a smaller concentration of sodium ions than blood plasma; The bile is very close to the blood plasma on the content of a number of ions.

Many ions, especially metal ions, are components of proteins, including enzymes. About 30% of all known enzymes for the complete manifestation of their catalytic activity need the presence of mineral substances, most often it is K, Na, MQ, Ca, Zn, Cu, Mn, Fe.

In the regulation of water-salt metabolism, the kidney and a group of special hormones play a decisive role.

In order to maintain water and salt metabolism at the proper level, several rules must be observed:

1. Use during the day the required amount of water

2. Try to use mineral, dining room (not carbonated) water.

3. Since the main source of mineral salts are fruits and vegetables must be regularly (every day) to use them into food.

4. If necessary, use dietary supplements (biological active additives) to a conventional diet, this method, you can quickly saturate the body with mineral salts.

Additional articles with useful information

Features of water exchange and mineral salts in children

Parents to raise a healthy child, you need to delve deeper into the physiological features of the younger generation. Children differ from adults not only in the growth and uncertain knowledge of multiplication table, but also processes occurring inside the body.

Mineral infringement violations in humans

Every month in the human body flows a large number of chemical reactions and, for various reasons, disorders are possible in this mechanism debugged.

The value of water and salts. All transformations of substances in the bodyperformed in the aquatic environment. Dissolves nutritional, enrolled in the body. Together with minerals, it takes part in the construction of cells and in many exchange reactions.

Participates in the regulation of body temperature; evaporated, it cools the body, preventing it from overheating; Transportdissolved.

And mineral salts create mainly the inner medium of the body, being the main component of the blood plasma, lymph and tissue fluid. They are involved in maintaining the osmotic pressure and reaction of blood plasma and tissue fluid. Some salts dissolved in the liquid blood are involved in the transfer of gases by blood.

Water and mineral salts are part of the digestive juices, which largely determines their value for digestion processes. And although neither water nor mineral salts are sources of energy in the body, normal intake and elimination of them from the body is a condition for its normal activity. It is enough to indicate that the water in an adult is about 65% of the body weight, and in children there are about 80%.

Man deprivation of water for several days deadly.

Exchange of water organism

The replenishment of the body with water occurs constantly due to the absorption of it from the digestive tract. A person needs a day 2-2.5 liters of water with normal food mode and normal ambient temperature. This amount of water comes from the following sources: 1) water consumed when drinking (about 1 l); 2) water contained in food (about 1 l); 3) Water, which is formed in the body when exchanging proteins, fats and carbohydrates (300-350 cm 3).

Basic organs removing water from the body, - Points, sweat glands, lungs and intestines. The kidneys per day from the OPGANISM removes 1.2-1.5 liters of water as part of urine. Potumin glands through the skin in the form of sweat is removed 500-700 cm 3 water per day. At normal temperature and humidity of air per 1 cm 2 of the skin, about 1 mg of water is distinguished every 10 minutes.

350 cm 3 of water is removed in the form of water vapors. This amount increases sharply in the deepening and efficiency of respiration, and 700-800 cm 3 of water can be distinguished during the day. Through the intestine with feces, 100-150 cm 3 of water is excreted per day. When the intestinal activity disorder, a larger amount of water may be excluded (with diarrhea), which leads to the dining of the body with water. For normal operation of the body, it is important that water flow into the body completely covered its consumption.

The ratio of the amount of water consumed to the amount of dedicated is water balance.

If the water is excreted from the body more than it goes into it, a feeling of thirst arises. As a result, the thirst for man dries water.

Salt exchange in the body

In the exclusion of the food diet of animal minerals, heavy disorders in the body and even death occur. With the presence of mineral substances, the phenomenon of excitability is connected - one of the main properties of the living. The growth and development of bones, nerve elements, muscles depend on the content of minerals. They determine the blood reaction (pH), contribute to the normal activity of the heart and nervous system, are used to form hemoglobin (), gastric acid hydrochloric acid ().

Mineral salts create so necessary for the vital cells of the cells defined.

With mixed nutrition, the adult man gets all the mineral you need in sufficient quantities. Only the cook salt is added to the food of a person when it is culinary processing. A growing children's body especially needs to be addressed to many minerals.

Minerals have an important impact on the development of the child. With the exchange of calcium and phosphorus, bone growth is associated, the timing of the charging cartilage and the state of oxidative processes in the body. With insufficient flow of calcium with food or depletion of the body for any reason, the bone tissue gives in to maintain a homeosta in it. affects the excitability of the nervous system, blood clotting, protein and fatty metabolism in the body. It is necessary not only for the growth and development of bone tissue, but also for the normal functioning of the nervous system, most of the ferrous and other organs.

It is an integral part of blood hemoglobin.

Table 18

Content of elements in the human body

Elements	Contents in the body (in%)	Elements	Contents in the body (in%)
	1,5		Minor quantities
	1.0		Minor quantities
	0,35		»
	0,25		»
	0,15		»
	0,15		»
	0,05		»
	0,004		»
	0,00004		»
			»

Regulation of water and salt metabolism

Constancy Osmoticthe pressure of the inner medium of the body, determined by the content of water and salts, is regulated by the organism.

With a lack of water in the body, the tissue fluid rises. This leads to the irritation of special receptors located in the tissues - OSSORTERS. The pulses from them on special nerves are sent to the brain to the center of regulating the water-salt exchange. From there, the excitation is sent to the urior of the internal secretion - the pituitary gland, which highlights the special hormone, causing the urging delay. Reducing the separation of water with urine restores disturbed equilibrium. This example clearly shows the interaction of nerve and humoral mechanisms for the regulation of physiological functions.

Regulation of fats.

An increase in blood glucose concentration reduces the collapse of lipids and activates their synthesis. A decrease in glucose concentration in the blood, on the contrary, inhibits the synthesis of lipids and enhances their splitting. Thus, the relationship between fat and carbohydrate exchanges is aimed at ensuring the energy needs of the body.

Hormone of the brain layer of adrenal glands - adrenaline, somatotropic hormone pituitary glands, thyroid hormone - tyroxin With prolonged effect, the fatty depot reduce.

The sympathetic nervous system is influenced by the exchange (it slows down the synthesis of lipids and enhances their decay) and the parasympathetic nervous system (contributes to fat deposition).

Nervous influences for fatty exchange are controlled by the hypothalamus.

Water is an integral part of all cells and human tissues. The water in an adult is 60% of the body weight, and in a newborn - 75%. It is a medium in which the metabolic processes are carried out in cells, organs and tissues. Continuous flow of water into the body is one of the main conditions for maintaining its livelihoods.

The main mass - 71% of all water in the body - is part of cell protoplasm, making up intracellular water.

Extracellular water It is in the composition fabric fluid (about 21%) and water plasma blood (about 8%).

Depot of water - subcutaneous fiber.

Water balance is made up of its consumption and selection. With food, a person gets about 750 ml of water per day, in the form of beverages and clean water - about 630 ml. About 320 ml of water is formed in the process of metabolism during the oxidation of proteins, carbohydrates and fats. When evaporated from the surface of the skin and the alveoy of the lungs per day, about 800 ml of water is distinguished. With feces, 100 ml of water is derived. Consequently, the minimum daily need is about 1700 ml of water.

The flow of water is regulated by its need, manifesting a feeling of thirst. This feeling occurs when the drinking center of the hypothalamus is excited.

The body needs constant arrival not only water, but also mineral salts. Sodium, potassium and calcium are the most important.

Sodium (Na +) It is the main cation of extracellular liquids. Its content in the extracellular medium is 6 - 12 times higher than the content in the cells. Sodium in the amount of 3 - 6 g per day enters the body in the form of NaCl and is absorbed mainly in the subtle intestinal department. The role of sodium in the body is diverse. It participates in maintaining the osmotic pressure of extracellular and intracellular liquids, takes part in the formation of the potential of action, has an impact on the activities of almost all organism systems. Sodium balance in the body is mainly supported, mainly kidney activities.

Potassium (K +) It is the main cation of intracellular fluid. The cells contain 98% of potassium. The daily need for potassium is 2-3 g. The main source of potassium in food is products of plant origin. Potassium in the intestines is absorbed. Potassium is of great importance in the life of the body, since it supports the membrane potential and generates the potential of action. It also participates in the regulation of equilibrium of the acid-base state and maintains osmotic pressure in cells. Regulation of its removal is carried out mainly by the kidneys.

Calcium (CA 2+) It has high biological activity. It is the main structural component of the bones of the skeleton and teeth, which contains about 99% of the total calcium. During the day, an adult should receive with food 800-1000 mg of calcium. In large quantities, children need children due to intense growth of bones. Calcium is absorbed mainly in the duodenum. Approximately ¾ calcium is derived from the digestive tract and ¼ - kidneys. Calcium participates in the generation of the action potential, plays a certain role in muscle reduction, is the necessary component of the blood coagulation system, increases the reflex excitability of the spinal cord.

In the body, elements that are in small quantities play a significant role. They are called trace elements. These include: iron, copper, zinc, cobalt, molybdenum, selenium, chrome, nickel, tin, silicon, fluorine, vanadium. Most biologically significant trace elements are part of enzymes, vitamins, hormones.