Electrolyte balance and its violations in the human body

The electrolyte balance in the human body is equilibrium anions (potassium, sodium, etc.) and cations (organic acids, chlorine, etc.).

Disturbance of the exchange of potassium

The role of potassium in the organism is multifaceted. It is part of proteins, which causes an increased need for it when anabolic processes are activated. Potassium is involved in carbohydrate exchange - in the synthesis of glycogen; In particular, glucose passes inside the cells only with Cali. It also participates in the synthesis of acetylcholine, as well as in the process of depolarization and repolarization of muscle cells.

Disturbance of potassium exchange in the form of hypokalemia or hypercalemia accompany the diseases of the gastrointestinal tract quite often.

Hypokalemia may be a consequence of diseases accompanied by vomiting or diarrhea, as well as in disabilities of suction processes in the intestine. It may occur under the influence of long-term use of glucose, diuretics, heart glycosides, adrenolytic drugs and in insulin treating. Insufficient or incorrect preoperative preparation or postoperative maintenance of the patient - poor potassium diet, infusion of potassium solutions, can also lead to a decrease in potassium content in the body.

Potassium deficiency can manifest a feeling of tingling and gravity in the limbs; Patients feel severity in centuries, muscle weakness and fast fatigue. They are sluggish, they have a passive position in bed, slow intermittent speech; Disturbance can appear, transient paralysis and even disorders of consciousness - from drowsiness and spin to coma development. Changes from the cardiovascular system are characterized by tachycardia, arterial hypotension, an increase in the size of the heart, the appearance of systolic noise and signs of heart failure, as well as a typical picture of the ECG changes.

Hypokalemia simpotomas

Hypokalemia is accompanied by an increase in sensitivity to the action of muscle relaxants and the elongation of their action, slowing the awakening of the patient after surgery, atonium of the gastrointestinal tract. Under these conditions, hypokalemic (extracellular) metabolic alkalosis can be observed.

Correction of hypokalemia

Correction of the lack of potassium should be based on the exact calculation of its deficiency and is carried out under the control of the content of potassium and the dynamics of clinical manifestations.

During the correction of hypokalemia, it is necessary to take into account the daily need in it, equal to 50-75 mmol (2-3 g). It should be remembered that in different salts of potassium contains its different amount. Thus, 1 g of potassium is contained in 2 g of potassium chloride, 3.3 potassium citrate and 6 g of potassium gluconate.

Hypokalemia treatment

Potassium preparations are recommended to be administered as a 0.5% solution with glucose and insulin at a rate not exceeding 25 mmol per hour (1 g of potassium or 2 g potassium chloride). At the same time, careful control of the condition of the patient, the dynamics of laboratory indicators, as well as the ECG in order to avoid overdose.

At the same time, there are research and clinical observations showing that with pronounced hypokalemia, parenteral therapy is properly selected in terms of volume and set of drugs may and should include significantly more potassium preparations. In some cases, the amount of potassium intimidated 10 times exceeded the recommended dose; At the same time there was no hypercalemia. However, we believe that the overdose of potassium and the danger of unwanted effects is real. Caution with the introduction of large quaria potassium is needed, especially if it is not possible to ensure permanent laboratory and electrocardiographic control.

Hypercalemia reasons

Hypercalemia may be a consequence of renal failure (the removal of potassium ions from the body), massive transfusion of canned donor blood, in particular the long-term storage time, insufficiency of adrenal function, increased decay of tissues during injury; It may occur in the postoperative period, with an excessively rapid introduction of potassium preparations, as well as with acidosis and intravascular hemolysis.

Symptoms

Clinically hypercalemia is manifested by the feeling of "crawling of goosebumps", especially in the limbs. At the same time, impairment of muscles, a decrease or disappearance of tendon reflexes, disorders of the heart in the form of bradycardia. Typical ECG changes are to increase and pointed the teeth, lengthening the P-Q interval, the appearance of ventricular arrhythmia, up to the heart fibrillation.

Hypercalemia treatment

Hypercalemia therapy depends on its severity and causes. With pronounced hypercalemia, accompanied by severe heart activities, the re-intravenous administration of calcium chloride is shown - 10-40 ml of 10% solution. During moderate hypercalemia, you can use intravenous administration of glucose with insulin (10-12 UR insulin per 1 l 5% solution or 500 ml of 10% glucose solution). Glucose contributes to the movement of potassium from extracellular space into intracellular. With concomitant renal failure, peritoneal dialysis and hemodialysis is shown.

Finally, it should be borne in mind that the correction of the concomitant disorders of the acid-base state - alkalosis for hypokalemia and acidosis in hyperkalemia - also contributes to the elimination of potassium balance disorders.

Sodium exchange

Normal sodium concentration in blood plasma is 125-145 mmol / l, and in red blood cells - 17-20 mmol / l.

The physiological role of sodium is its responsibility for maintaining the osmotic pressure of extracellular fluid and the redistribution of water between the extracellular and intracellular medium.

Sodium deficiency can develop as a result of its losses through the gastrointestinal tract - with vomiting, diarrhea, intestinal fistulas, with loss of kidney during spontaneous polyuria or forced diuresis, as well as with abundant sweating through the skin. Less often, this phenomenon may be a consequence of glucocorticoid deficiency or excessive generation of antidiuretic hormone.

Hyponatremia Causes

Hyponatremia may occur in the absence of external losses - with the development of hypoxia, acidosis and other reasons causing an increase in the permeability of cell membranes. In this case, the extracellular sodium moves inside the cells, which is accompanied by hyponatremia.

Sodium deficiency causes a redistribution of fluid in the body: the osmotic pressure of blood plasma is reduced and intracellular hyperhydration occurs.

Symptoms of sodium deficiency

Clinically hyponatremia manifests quickly fatigue, dizziness, nausea, vomiting, decrease in blood pressure, convulsions, violations of consciousness. As can be seen, these manifestations are nonspecific, and to clarify the nature of the violations of the electrolyte balance and the degree of their severity, it is necessary to determine the sodium content in blood plasma and red blood cells. This is necessary for directed quantitative correction.

Hyponatremia Treatment

With a true sodium deficiency, the sodium solutions of chloride should be used, taking into account the magnitude of the deficit. In the absence of sodium losses, measures are needed to eliminate the reasons for increasing the permeability of membranes, the correction of acidosis, the use of glucocorticoid hormones, proteolytic enzyme inhibitors, mixtures of glucose, potassium and novocaine. This mixture improves microcirculation, contributes to the normalization of the permeability of cell membranes, prevents the reinforced transition of sodium ions inside the cells and thereby normalizes the sodium balance.

Hypernatremia Causes

Hypernatremia arises against the background of oliguria, limitations of injected fluids, with overpressing sodium, in the treatment of glucocorticoid hormones and ACTH, as well as in primary hyperaldosteroneism and Cushing syndrome. It is accompanied by an impaired water balance - extracellular hypershydration, manifested by thirst, hyperthermia, arterial hypertension, tachycardia. Evenkers can develop, increase intracranial pressure, heart failure.

Hypernatremia Treatment

Hypernatremia is eliminated by the appointment of aldosterone inhibitors (Veroshpiron), limiting sodium administration and normalization of water exchange.

Calcium exchange

In the normal functioning of the body of calcium plays an important role. It increases the tone of the sympathetic nervous system, congestives tissue membranes, reduces their permeability, increases blood clotting. Calcium has a desensitizing and anti-inflammatory effect, activates the macrophage system and the phagocytic activity of leukocytes. The normal content of calcium in the blood plasma is 2.25-2.75 mmol / l.

Hypocalcemia reasons

In many diseases of the gastrointestinal tract, disorders of calcium metabolism develop, resulting in an excess, or a deficiency of calcium containing blood plasma. Thus, with acute cholecystitis, acute pancreatitis, saworoduodenal stenosis, hypocalcemia occurs due to vomiting, calcium fixation in the foci of steatonecosis, increase the content of glucagon. Hypocalcemia may occur after massive hemotransphusion therapy due to calcium binding with citrate; In this case, it can also be relative in nature due to the flow of significant quasi in the body contained in canned blood. The decrease in calcium content may be observed in the postoperative period due to the development of functional hypocorticism, which causes calcium care from blood plasma into the bone depot.

Hypocalcemia symptoms

Hypocalcemia treatment

Therapy of hypocalcemic conditions and their prevention consist in intravenous administration of calcium-chloride or gluconate drugs. The prophylactic dose of calcium chloride is 5-10 ml of a 10% solution, therapeutic - may increase to 40 ml. It is preferable to carry out therapy with weak solutions - not higher than 1 percent concentration. Otherwise, the sharp increase in the calcium content in the blood plasma causes the chims of calcitonin by the thyroid gland, which stimulates its transition to the bone depot; In this case, the concentration of calcium in the blood plasma may fall below the original.

Hypercalcemia reasons

Hypercalcemia for diseases of the gastrointestinal tract is much less common, but it may occur under peptic ulcer, stomach cancer and other diseases, accompanied by the depletion of the function of the adrenal cortex. Hypercalcemia is manifested by muscle weakness, total patient intensity; Possible nausea, vomiting. With the penetration of significant amounts of calcium inside the cells, lesions of the brain, heart, kidneys, pancreas can develop.

Magnesium exchange in human body

The physiological role of magnesium is to activate the functions of a number of enzyme systems - the atphase, alkaline phosphatase, cholinesterase, etc. It is involved in the implementation of the transmission of nerve impulses, ATP synthesis, amino acids. The concentration of magnesium in the blood plasma is 0.75-1 mmol / l, and in red blood cells - 24-28 mmol / l. Magnesium is quite consistently persisted in the body, and it is infrequently developing losses.

Gipicomagnation - Causes and Treatment

Nevertheless, the hypomagnemia occurs during long-term parenteral nutrition and pathological losses through the intestines, as magnesium is absorbed in the small intestine. Therefore, magnesium deficiency can develop after an extensive resection of the small intestine, with diarrhea, sublicasy fistulas, during the intestinal paresis. The same violation may occur against the background of hypercalcemia and hypernatremia, in the treatment of cardiac glycosides, with diabetic ketoacidosis. Magnesium deficiency is manifested by an increase in reflex activity, cramps or muscle weakness, arterial hypotension, tachycardia. Correction is carried out by solutions containing magnesium sulfate (up to 30 mmol / day).

Hypermagnias - causes and correction

Hypermagnias occurs less frequently of the hypomagnia. The main causes are renal failure and massive tissue destruction leading to the release of intracellular magnesium. HyperMagnias can develop against the background of insufficiency of adrenal function. It is manifested by a decrease in reflexes, hypotension, muscle weakness, violations of consciousness, up to the development of deep coma. HyperMagnias is corrected by eliminating its causes, as well as peritoneal dialysis or hemodialysis.

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The inner medium of the body is characterized by the volume, concentration of electrolytes, pH of liquids, which determine the conditions for normal operation of functional systems.

Our body is more than half consists of water, which is about 50 liters (depends on gender, age, mass). The water in the body is in the associated state. In total, three sectors of water are distinguished (the first two form extracellular space):

• intravascular sector;
• interstitial sector;
• intracellular sector.

The body with fairly high accuracy regulates the relationship between sectors, the constancy of the osmotic concentration, the level of electrolytes.

The electrolytes dissociate on the ions, unlike non-electrolytees (urea, creatinine), which ions do not form. Ions are positively or negatively charged (cations and anions). The internal environment of the body is electronteral.

Cations and anions provide the bioelectric potential of membranes, catalyzed the metabolism, determine the pH, participate in the energy exchange and hemocoagulation processes.

Osmotic pressure is the most stable parameter of the inner environment of the body. In the intracellular sector, the osmotic pressure is determined by the concentration of potassium, phosphate and protein; In the extracellular sector - the content of sodium cations, chlorine and protein anions. The more these particles, the greater the osmotic pressure, which depends on the concentration of osmotically active particles in the solution and is determined by their number. Cell membranes freely pass water, but do not let other molecules. For this reason, water always goes there, where the concentration of molecules is greater. Normally, water-electrolyte exchange is subordinated to the process of producing energy and the removal of metabolites.

Acid-alkaline

The constancy of the volume, composition and pH of the fluid cell ensure its normal functioning. Regulatory mechanisms that control this constancy are interrelated. Maintaining the constancy of the acid-alkaline state of the inner medium is carried out through the buffer system, light, kidney, other organs. Self-regulation is to enhanced hydrogen ions with excessive acidication of the body, and their delay - when parsing.

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Water and electrolyte exchange is one of the links that ensure the dynamic constancy of the inner environment of the body - homeostasis. Plays an important role in metabolism. The water content in the body reaches 65-70% of body weight. It is customary to share water on intra and extracellular. Intracellular water is about 72% of all water. Extracellular water is divided into an intravascular, circulating in the composition of blood, lymph and the spinal fluid, and the interstitial (interstitial) fluid in the intercellular spaces. At extracellular fluid accounts for about 28%.

The equilibrium between outside and intracellular fluids is maintained by their electrolyte composition and neuro-endocrine regulation. The role of potassium and sodium ions is especially great. They are selectively distributed on both sides of the cell membrane: potassium - inside the cells, sodium - in extracellular fluid, creating a osmotic concentration gradient ("Potassium-sodium pump"), providing tours of fabrics.

In the regulation of water-salt metabolism, the leading role belongs to aldosterone and antidiuretic hormone pituitary (ADG). Aldosterone reduces sodium selection as a result of enhancing its reabsorption in kidney channels, ADG controls water kidney elimination by affecting its reabsorption.

The recognition of water exchange disorders consists in measuring the total amount of water in the body by breeding. It is based on the introduction of indicators in the body (antipirine, heavy water), which are evenly distributed in the body. Knowing the number of the entered indicator TOiW subsequently determining its concentration FROM,you can determine the total volume of fluid that will be equal K / s.The volume of circulating plasma is determined by dying dilution (T-1824, Congo-mouth), not passing through the walls of capillaries. Extracellular (extracellular) fluid is measured by the same dilution method using inulin, radioisotope 82 wg, not penetrating the cells. The volume of the interstitial fluid is determined by subtraction from the volume of extracellular water of the plasma volume, and the intracellular fluid is determined, the subtraction of extracellular fluid from the total volume of water.

Important data on violation of the water balance in the body is obtained when studying the hydrophilicity of tissues (sample Mac-Kraura and Oldrich). An isotonic solution of sodium chloride is introduced into the skin before the advent of infiltrate the magnitude with the pea and monitor its resorption. The more the body loses the water, the faster the infiltrate disappears. In calves, patients with dyspepsia, the blister is absorbed after 1.5-8 min (in healthy - after 20-25 minutes), in horses in mechanical obstruction of the intestine - after 15-30 minutes (normally - after 3-5 h).

Disorders of water and electrolyte exchange are manifested in various clinical forms. Dehydration, water delay, hypo and hypernatremia, hypo and hypernatremia have the greatest value.

Dehydration (Exicosis, hypiohydrium, dehydration, negative water balance) with a simultaneous decrease in the osmotic pressure of the extracellular fluid (hyposmolar dehydration) are observed with the loss of a large amount of fluid containing electrolytes (with vomiting, extensive burns), obstruction of the intestine, swallowing disorders, diarrhea, hyperhydrons, polyuria . Hyperosmolar dehydration is noted when the water decrease occurs with a small loss of electrolytes, and the lost liquid is not compensated by drinking. The predominance of water loss over the release of electrolytes leads to an increase in the osmotic concentration of extracellular fluid and the water outlet from the cells in the intercellular space. This form of the excacosis is often developing with young people with hyperventilation of the lungs, diarrhea.

Dehydrutation syndrome manifests general weakness, anorexia, thirst, dry mucous membranes and leather. Swallowing is difficult due to the deficiency of saliva. Oliguria develops, urine has a high relative density. The muscles turgor is lowered, the enofalmia occurs, the elasticity of the skin is reduced. Reveal negative water balance, blood thickening, reducing body weight. The loss of 10% of water leads to difficult consequences, and 20% to death.

Hyperhydria (Water delay, swelling, hyperhydration) occurs with a simultaneous decrease in or increasing the osmotic pressure of the fluid (hypo- and hyperosmolar hyperhydration). Hyposmolar hyperhymitationregistered with an irrational introduction into the body of an animal (inward or parenterally) large quantities of phenomena, especially after injury, surgical intervention, or with a decrease in the selection of water by the kidneys. Hyperosmolar hyperhymitationfind with excessive introduction to the body of hypertensive solutions in volumes exceeding the possibility of rapidly eliminating them, with heart disease, kidney, liver leading to edema.

Hyperhydrate syndrome (Even) is characterized by lethargy, the appearance of test edema, sometimes the diets of serous cavities is developing. Body mass increases. Diuresis increases, urine low relative density.

The sodium and potassium content in the feed, blood and plasma, tissues and body fluids is determined on a flame photometer, chemical methods or using radioactive isotopes 24 Na and 42 K. in solid blood sodium cattle contains 260-280 mg / 100 ml (113, 1-121.8 mmol / l), plasma (serum) -320-340mg / 100ml (139.2-147.9 mmol / l); Potassium - in red blood cells - 430-585 mg / 100 ml (110.1-149.8 mmol / l), in solid blood - 38-42 mg / 100 ml (9.73-10.75 mmol / l) and plasma -16-0 mg / 100 ml (4.1-5.12 mmol / l).

Sodium- The main cation of extracellular liquid (more than 90%) performing the functions of maintaining osmotic equilibrium and as a component of buffer systems. The value of the extracellular space depends on the sodium concentration: with its excess, the space increases, with a lack of decreases.

Hyponatremia It may be relative with the abundant receipt of water into the body and absolute with sodium losses from then, with diarrhea, vomiting, burn, an alimentary dystrophy, having missed it with a diet.

Hypernamentia Develops due to the loss of water or excess sodium chloride in the stern, with nephrisosis, jade, wrinkled kidney, aqueous starvation, inadequate diabetes, hypersection of aldosterone.

Hyponatremia syndrome It is manifested by vomiting, general weakness, decrease in body weight and water content in the body, decreasing and perversion of appetite, falling blood pressure, acidosis and decrease in plasma sodium levels.

Under hypernatremia syndrome observe salivation, thirst, vomiting, increase body temperature, hyperemia of mucous membranes, breathing and pulse, excitation, seizures; The content of sodium in the blood increases.

Potassiumparticipates in maintaining intracellular osmotic pressure, acid-alkaline equilibrium, neuromuscular excitability. Inside the cells there is 98.5% of potassium and only 1.5% in extracellular fluid.

Hypokalemia It arises due to potassium deficiency in the feed, with vomiting, diarrhea, edema, ascites, aldosterone hypersecrection, the use of saluretics.

Hypercalemia It develops with excessive flow of potassium with feed or reducing its excretion. Increased potassium content is celebrated with erythrocyte hemolysis and elevated tissue decay.

Hypokalemia syndrome It is characterized by anorexia, vomiting, atonium of the stomach and intestines, muscular weakness; Registered heart weakness, paroxysmal tachycardia, teeth compass T.on ECG, loss of body weight. Blood potassium level is reduced.

With hypercalemia The function of myocardium (deafness of tones, extrasystolia, bradycardia, decrease in blood pressure, intraventricular blockade with ventricular flicker, prong T.high and acute, complex QRS.extended, Teeth Rreduced or disappear).

Hypercalee intoxication syndrome accompanied by general weakness, oliginia, lowering neuromuscular excitability and decompensation of the heart.

Biological chemistry LELEVICH Vladimir Valerianovich

Chapter 29. Water-electrolyte exchange

The distribution of fluid in the body

To perform specific functions, the cells require a steady habitat, including stable nutrient provision and constant exchanging products. The basis of the inner medium of the body is fluid. They account for 60 to 65% of body weight. All body fluids are distributed between the two main liquid compartments: intracellular and extracellular.

Intracellular fluid is a liquid contained inside the cells. In adults, an intracellular liquid accounts for 2/3 of the entire liquid, or 30% of the body weight. Extracellular fluid - liquid outside cells. In adults, the extracellular liquid accounts for 1/3 of the entire fluid, or 20 - 25% body weight.

Extracellular fluid is divided into several types:

1. Interstitial fluid - fluid surrounding cells. Lymph is an interstitial fluid.

2. Intravascular fluid - liquid located inside the vascular bed.

3. Translationllular fluid contained in specialized body cavities. The transcellular fluid includes the spinal, pericardial, pleural, synovial, intraocular, as well as digestive juices.

Composition of liquids

All fluids consist of water and dissolved in it substances.

Water is the main component of the human body. In adult men, water is 60% and in women - 55% of body weight.

The factors affecting the amount of water in the body include.

1. Age. As a rule, the amount of water in the body decreases with age. In a newborn, the amount of water is 70% of body weight, aged 6 - 12 months - 60%, in an elderly man 45 - 55%. Reducing the amount of water with age occurs due to a decrease in muscle mass.

2. Fat cells. It contains little water, so the amount of water in the body decreases with increasing fat content.

3. Paul. The female organism has a relatively less water, as it contains relatively more fat.

Molted substances

In the body fluids, there are two types of solutes - non-electrolytes and electrolytes.

1. Neelectricates. Substances that are not dissociated in the solution and are measured by mass (for example mg per 100 ml). Clinically important non-electrolytes include glucose, urea, creatinine, bilirubin.

2. Electrolytes. Substances that dissociate in the solution on cations and anions and their content is measured in Milliquivalent per liter [MEKV / L]. The electrolyte composition of the liquids is presented in the table.

Table 29.1. Main electrolytes of organism liquid compartments (average values \u200b\u200bare given)

The content of electrolytes, MEKV / L	Extracellular fluid		Intracellular liquid
	plasma	interstitial
Na +.	140	140	10
K +.	4	4	150
Ca 2+.	5	2,5	0
Cl -	105	115	2
PO 4 3-	2	2	35
HCO 3 -	27	30	10

The main extracellular cations are Na +, Ca 2+, and intracellular K +, Mg 2+. Outside the cells dominate the anions of the CL -, NSO 3 -, and the main anion of the cell is PO 4 3-. The intravascular and interstitial fluid have the same composition, since the endothelium of capiles is fluent in fluid for ions and water.

The difference in the composition of extracellular and intracellular liquids is due to:

1. The impermeability of the cell membrane for ions;

2. Functioning of transport systems and ion channels.

Characteristics of liquids

In addition to the composition, the general characteristics (parameters) of fluids have important. These include: volume, osmolayality and pH.

Liquid volume.

The volume of fluid depends on the amount of water that is currently present in a particular space. However, water passes as much, mainly due to Na +.

Adult body fluids have volume:

1. Intracellular liquid - 27 l

2. Extracellular liquid - 15 liters

Interstitial liquid - 11 l

Plasma - 3 l

Translationllular liquid - 1 l.

Water, biological role, water exchange

Water in the body is in three states:

1. The constitutional (firmly connected) water is included in the structure of proteins, fats, carbohydrates.

2. Weakly wounded water of diffusion layers and external hydrate shells of biomolecules.

3. Free, mobile water, is a medium in which electrolytes and nicerolites dissolve.

There is a state of dynamic equilibrium between associated and free water. So the synthesis of 1 g of glycogen or protein requires 3 g H 2, which moves from free state to the associated.

The water in the body performs the following biological functions:

1. Solvent of biological molecules.

2. Metabolic - participation in biochemical reactions (hydrolysis, hydration, dehydration, etc.).

3. Structural - ensuring the structural layer between the polar groups in biological membranes.

4. Mechanical - contributes to the preservation of intracellular pressure, cell shape (turgor).

5. Heat balance regulator (saving, distribution, heat recovery).

6. Transport - ensuring the transfer of dissolved substances.

Water exchange

The daily need for an adult water is about 40 ml per 1 kg of mass or about 2500 ml. The time of staying water molecule in the body of an adult is about 15 days, in the body of an infant - up to 5 days. There is a constant balance between the flow and loss of water (Fig. 29.1).

Fig. 29.1 Water balance (external water exchange) of the body.

Note. Water loss through the skin is composed of:

1. Immountless water loss - evaporation from the surface of the skin at a rate of 6 ml / kg of mass / hour. In newborns, the speed of evaporation is greater. These water losses do not contain electrolytes.

2. Tangible water losses - sweating, in which water is lost and electrolytes.

Regulation of extracellular fluid

Significant fluctuations in the volume of the interstitial part of the extracellular fluid may be observed without a pronounced effect on the function of the body. The vascular part of the extracellular fluid is less resistant to change and must be carefully monitored so that the tissues are adequately supplied with nutrients while simultaneously continuously removing metabolic products. The volume of extracellular fluid depends on the amount of sodium in the body, so the regulation of the extracellular fluid is associated with the regulation of sodium exchange. Aldosterone occupies a central place in this regulation.

Aldosterone acts on the main cells of the collecting tubes, i.e. the distal part of the renal tubules - to that section in which about 90% of the filtered sodium is rebupping. Aldosterone binds to intracellular receptors, stimulates gene transcription and protein synthesis that open sodium channels in the apical membrane. As a result, the elevated amount of sodium is included in the main cells and activates Na +, K + - the atpasis of the baselateral membrane. The reinforced transport of K + into the cell in exchange for Na + leads to increased secretion to + through the potassium channels into the lumen of the Channel.

RENIN-ANGIOTENZIN SYSTEM ROLE

The renin-angiotensin system plays an important role in regulating the osmolality and the volume of extracellular fluid.

Activation of the system

With a decrease in blood pressure in the armiests of the kidney, if the decrease in sodium content in the distal tubules in granular cells of the YuCSTAGLOMERAL kidney apparatus is synthesized and secreted into the blood of proteolytic enzyme-renin. Further activation of the system is shown in Fig. 29.2.

Fig. 29.2. Activation of the Renin-angiotensin system.

Atrial sodium system

The atrial sodretric factor (PNF) is synthesized by atriums (mainly right). The PNF is a peptide and stands out in response to any events, leading to an increase in the volume or increase in the pressure of the accumulation of the heart. The PNF, in contrast to angiotensin II and aldosterone, reduces vascular volume and blood pressure.

The hormone has the following biological effects:

1. Enhances the excretion of sodium and water kidneys (by enhancing filtration).

2. Reduces the synthesis of renin and the emission of aldosterone.

3. Reduces the emission of ADG.

4. Causes direct vasodilation.

Disorders of water and electrolyte metabolism and acid-base equilibrium

Dehydration.

Dehydration (dehydration, water failure) leads to an emptiness of the volume of extracellular fluid-hypovolemia.

Develops due to:

1. Abnormal loss of fluid through the skin, kidney, gastrointestinal tract.

2. Reducing water intake.

3. Displacement of fluid in the third space.

A pronounced decrease in the volume of extracellular fluid can lead to hypovolemic shock. Prolonged hypovelee can cause renal failure.

Distinguish 3 types of dehydration:

1. Isotonic - uniform loss Na + and H 2 O.

2. Hypertensive - lack of water.

3. Hypotonic - lack of fluid with prevalence of the lack of Na +.

Depending on the type of fluid loss, dehydration is accompanied by a decrease in or increasing the indicators of osmolality, the core, the level NA + and K +.

Edema - one of the most severe disorders of the water and electrolyte exchange. Edema is an excessive accumulation of fluid in an interstitial space, for example on legs or pulmonary intersets. At the same time, swelling of the main substance of the connective tissue occurs. Even fluid is always formed from blood plasma, which in pathological conditions is not able to hold water.

Entries are developing as a result of the factors:

1. Reducing the concentration of albumin in blood plasma.

2. Increasing the level of ADG, aldosterone causing water delay, sodium.

3. Increase the permeability of capillaries.

4. Increased capillary hydrostatic blood pressure.

5. Excess or redistribution of sodium in the body.

6. Blood circulation impairment (for example, heart failure).

Disorders of the essential equilibrium

Violations occur if there is no ability to maintain the mechanisms of support to prevent shifts. There may be two extreme states. Acidosis - increasing the concentration of hydrogen ions or the base loss leading to a decrease in the pH. Alkalosis is an increase in the concentration of bases or a decrease in the concentration of hydrogen ions causing an increase in pH.

The change in blood pH is below 7.0 or above 8.8 cause the death of the body.

Three forms of pathological conditions lead to a violation of Cor:

1. Violation of carbon dioxide is light.

2. Excessive products of acidic products with fabrics.

3. Disorders of the reasons with urine, feces.

From the point of view of development mechanisms, several types of disorders of Cor are distinguished.

The respiratory acidosis is caused by increasing RSO 2 above 40mm. RT. Art due to hypoventilation for diseases of the lungs, CNS, hearts.

The respiratory alkalosis is characterized by a decrease in RSO 2 less than 40mm. RT. Art., It is the result of an increase in alveolar ventilation and is observed in mental excitation, lung diseases (pneumonia).

Metabolic acidosis is a consequence of the primary reduction in blood plasma bicarbonate, which is observed in the accumulation of non-volatile acids (ketoacidosis, lactoacidosis), loss of bases (diarrhea), reducing the excretion of kidney acids.

Metabolic alkalosis - occurs with increasing level of blood plasma bicarbonate and is observed with the loss of acid content of the stomach during vomiting, the use of diuretics, Cushing syndrome.

Mineral components of fabrics, biological functions

The human body discovered most elements found in nature.

From the point of view of quantitative content in the body, they can be divided into 3 groups:

1. Microelements-content in the body of more than 10-2%. These include - sodium, potassium, calcium, chloride, magnesium, phosphorus.

2. Microelements - the content in the body from 10-2% to 10-5%. These include - zinc, molybdenum, iodine, copper, etc.

3. Ultramic-elements - the content in the body is less than 10-5%, for example, silver, aluminum, etc.

In cells, minerals are in the form of ions.

Basic biological functions

1. Structural - participate in the formation of spatial structures of biopolymers and other substances.

2. Cofactor - participation in the formation of active enzyme centers.

3. Osmotic - maintenance of osmolarity and volume of liquids.

4. Bioelectric - generation of membrane potential.

5. Regulatory - inhibition or activation of enzymes.

6. Transportation - participation in the transfer of oxygen, electrons.

Sodium, biological role, exchange, regulation

Biological role:

1. Maintain water balance and osmolality of extracellular fluid;

2. Maintain the osmotic pressure, the volume of extracellular fluid;

3. Regulation of acid-base equilibrium;

4. Maintaining neuromuscular excitability;

5. Transmission of the nerve impulse;

6. Secondary active transport of substances through biological membranes.

The human body contains about 100 grams sodium, which is distributed mainly in extracellular fluid. Sodium comes with food in the amount of 4-5 gr per day and is absorbed in the proximal division of the small intestine. T? (half-day half-time) for adults 11-13 days. Sodium is distinguished from the body with urine (3.3 Gy / day), then (0.9 Gy / day), feces (0.1 g / day).

Regulation of exchange

The main regulation of the exchange is carried out at the kidney level. They are responsible for the excretion of excess sodium and contribute to its preservation by deficiency.

Renal excretion:

1. Enhance: angiotensin-II, aldosterone;

2. Reduces the PNF.

Potassium, biological role, exchange, regulation

Biological role:

1. Participation in maintaining osmotic pressure;

2. Participation in maintaining acid-base equilibrium;

3. Conducting a nervous impulse;

4. Maintaining neuromuscular excitation;

5. Reducing muscles, cells;

6. Activation of enzymes.

Potassium is the main intracellular cation. The human body contains 140 g potassium. About 3-4 g of potassium flows daily, which is absorbed in the proximal division of the small intestine. T? Potassium is about 30 days. It is derived from the urine (3 g / day), the feces (0.4 g / sut), then (0.1 g / day).

Regulation of exchange

Despite the small content K + in the plasma, its concentration is regulated very strictly. Admission to + in cells enhance adrenaline, aldosterone, insulin, acidosis. The total balance of K + is adjustable at the kidney level. Aldosterone enhances the allocation of K + by stimulating secretion according to potassium channels. In hypokalemia, kidney regulatory capabilities are limited.

Calcium, biological role, exchange, regulation

Biological role:

1. The structure of bone tissue, teeth;

2. Muscular cut;

3. The excitability of the nervous system;

4. Intracellular hormone intermediary;

5. blood coagulation;

6. Activation of enzymes (tripsin, succinate dehydrogenase);

7. Secretor activity of ferrous cells.

The body contains about 1 kg of calcium: in the bones - about 1 kg, in soft tissues, preferably extracellularly - about 14 g with food, 1 g per day, and 0.3 g / day is absorbed. T? For calcium contained in the body for about 6 years, for calcium skeleton bones - 20 years.

Calcium plasma contains in two types:

1. Ustiffundable proteins (albumin), biologically inactive - 40%.

2. Diffund, consisting of 2 fractions:

Ionized (free) - 50%;

Integrated, associated with anions: phosphate, citrate, carbonate - 10%.

All forms of calcium are in a dynamic reversible equilibrium. Only ionized calcium has physiological activity. Calcium is released from the body: Calval - 0.7 g / day; with urine 0.2 g / day; From then 0.03 g / day.

Regulation of exchange

In the regulation of Ca 2+ exchange, 3 factor are:

1. Paranthgump - increases the yield of calcium from bone tissue, stimulates reabsorption in the kidneys, and activating the conversion of vitamin D in its form D 3 increases the absorption of calcium in the intestine.

2. Calcitonine - reduces the yield of Ca 2+ from bone tissue.

3. The active form of vitamin D - vitamin D 3 stimulates calcium suction in the intestine. Ultimately, the action of the parathgamon and vitamin D is aimed at increasing the concentration of Ca2 + in extracellular fluid, including plasma, and the calcitonin action is to reduce this concentration.

Phosphorus, biological role, exchange, regulation

Biological role:

1. Education (together with calcium) bone structure;

2. The structure of DNA, RNA, phospholipids, coenzymes;

3. Education of macroehers;

4. Phosphorylation (activation) of substrates;

5. Maintaining acid-base equilibrium;

6. Regulation of metabolism (phosphorylation, dephosphorylation of proteins, enzymes).

The body contains 650 g of phosphorus, of which in the skeleton - 8.5%, in the cells of soft tissues - 14%, in extracellular fluid - 1%. About 2 g per day arrives, from which up to 70% is absorbed. T? Calcium soft tissues - 20 days, skeleton - 4 years. Phosphorus is derived: with urine - 1.5 g / day, with a fee - 0.5 g / day, from then - about 1 mg / day.

Regulation of exchange

Paranthgumon enhances the phosphorus outlet from bone tissue and eliminating it with urine, and also increases suction in the intestine. Usually, the concentration of calcium and phosphorus in the blood plasma changes in the opposite way. However, not always. With hyperparathyroidism, both levels of both are rising, and when children's rickets are reduced by the concentrations of both.

Essential trace elements

Essential trace elements - trace elements without which the body cannot grow, develop and make their natural life cycle. Essential elements include: iron, copper, zinc, manganese, chrome, selenium, molybdenum, iodine, cobalt. They have established the main biochemical processes in which they are involved. The characteristic of vital trace elements is shown in Table 29.2.

Table 29.2. Essential trace elements, brief description.

Micro element	Contents in the body (on average)	Main functions
Copper	100 mg	Component of oxidases (cytochromoxidase), participation in the synthesis of hemoglobin, collagen, immune processes.
Iron	4.5 g	The component of the gem-containing enzymes and proteins (HB, MB, etc.).
Iodine	15 mg	We are necessary for the synthesis of thyroid hormones.
Cobalt	1.5 mg	The component of vitamin B 12.
Chromium	15 mg	Participates in the binding of insulin with receptors of cell membranes, forms a complex with insulin and stimulates the manifestation of its activity.
Manganese	15 mg	Cofactor and activator of many enzymes (pyruvatkinase, decarboxylase, superoxiddismutase), participation in the synthesis of glycoproteins and proteoglycans, antioxidant effect.
Molybdenum	10 mg	Cofactor and activator of oxidases (xanthine oxidase, serinexidase).
Selenium	15 mg	It is part of selenoproteins, glutathioneer peroxidase.
Zinc	1.5 g	Enzyme cofactor (LDH, carboangeyndasis, RNA and DNA polymerase).

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Basic physico-chemical concepts:

Osmolarity - The concentration unit of the substance reflecting its content in one solvent liter.

Osmolar - A single concentration unit reflecting its content in one kilogram of the solvent.

Equivalence - An indicator used in clinical practice to reflect the concentration of substances in the dissociated form. Equal to the amount of Milimol multiplied by valence.

Osmotic pressure - The pressure that needs to be applied to stop the movement of water through the semipermeable membrane along the concentration gradient.

In the organism of an adult, water is 60% of body weight and distributed in three main sectors: intracellular, extracellular and intercellular (intestinal mucus, serous cavity liquid, spinal fluid). Extracellular space includes intravascular and interstitial compartments.. The capacity of the extracellular space is 20% of body weight.

Regulation of water sectors is carried out according to the Osmosis laws, the sodium ion is played by the main role, and the concentration of urea and glucose is played. Blood plasma osmolarity is equal to 282 -295 MOS / l.. It is calculated by the formula:

P. oSM = 2  Na. +  +2  TO +  +  Glucose +  urea

The resulting formula reflects the so-called. Calculated osmolarity, adjustable through the content of the listed components and the amount of water as a solvent.

The term measured osmolarity reflects the actual value determined by the instrument osmometer. So, if the measured osmolarity exceeds the calculated, then in the blood plasma circulate unaccounted osmotically active substances, such as dextran, ethyl alcohol, methanol, etc.

The main ion of extracellular fluid is sodium. Normally its plasma concentration 135-145 mmol / l . 70% of all sodium organism is intensively involved in the exchange processes and 30% is associated in bone tissue. Most of the cell membranes are impenetrable for sodium. Its gradient is maintained by active removal of cells by Na / K ATP-Ase

In kidneys, 70% of the total sodium is reabidated in proximal tubules and another 5% can be reabidated in distal under the action of aldosterone.

Normally, the volume of fluid entering the body is equal to the volume of fluid allocated from it. The daily exchange of fluid is 2 - 2.5 liters (Table 1).

Table 1. Approximate daily liquid balance

Arrival		Selection
way	Number (ml)	way	Number (ml)
Receive fluids
		Puspiration
Metabolism
Total	2000 - 2500	Total	2000 - 2500

Significantly increase water loss with hyperthermia (10 ml / kg per degree above 37 0 C), tachipne (10 ml / kg with CH  20), hardware respiration without moisturizing.

Dzhiedriy

Pathophysiology of water exchange disorders.

Disorders can be associated with a fluid deficiency (dehydration) or with its excess (hyperhydration). In turn, each of the above disorders may be isotonic (with the normal amount of blood plasma osmoticity), hypotonic (when the plasma osmolarity is reduced) and hypertonic (plasma osmolarity significantly exceeds the permissible boundaries of the norm).

Isotonic dehydration - noted both water deficiency and salts deficiency. Plasma osmolarity is normal (270-295 mosm / l). The extracellular space suffers, it is reduced by hypovolemia. It is observed in patients with losses from the gastrointestinal tract (vomiting, diarrhea, fistula), blood loss, with peritonitis and burn disease, polyuria, in the case of uncontrolled diuretics.

Hypertensive dehydration is a state characterized by an absolute or predominant fluid deficiency with an increase in plasma osmolarity. NA\u003e 150 mmol / l, plasma osmolarity\u003e 290 mosm / l. It is observed in case of insufficient water intake (inadequate probe food - 100 ml of water should be introduced for every 100 kcal), gastrophonic diseases, loss of hypotonic pneumonia, tracheobronchites, fever, tracheostomy, polyuria, osmodioresis during non-car diabetes.

Hypotonic dehydration - there is a shortage of water with the prevailing loss of electrolytes. The extracellular space is reduced, and the cells are oversaturated with water. NA<13О ммоль/л, осмолярность плазмы < 275мосм/л. Наблюдается при состояниях, связанных с потерей солей (болезнь Аддисона, применение диуретиков, слабительных, осмодиурез, диета, бедная натрием), при введении избыточного количества инфузионных растворов, не содержащих электролиты (глюкоза, коллоиды).

Water deficiency.The cause of water deficiency may be either insufficient entry, or excessive losses. The lack of admission is rarely found in clinical practice.

Causes of water loss:

1. Nonachar diabetes

Central

Nephrogenic

2. Excessive sweating

3. Professional diarrhea

4. Hypervetilation

In this case, there is a loss of non-pure water, but a hypotonic fluid. The increase in the osmolarity of the extracellular fluid causes the movement of intracellular water into the vessels, however, this does not compensate for hyperosmolarity completely, which increases the content of antidiuretic hormone (ADG). Since such dehydration is partially compensated from the intracellular sector, the clinical signs will be weakly expressed. If the reason is not kidney losses, then urine becomes concentrated.

The central unacceptable diabetes often occurs after neurosurgical operations and CMT. The reason is damage to the pituitary gland or hypothalamus, which is expressed in reducing the synthesis of ADG. For the disease, polydipsia and polyuria without gluezuria are characteristic. Urine osmolarity is lower than plasma osmolarity.

Nephrogenic unacciation diabetes develops, most often, secondary, as a result of chronic kidney diseases and sometimes, as a side effect of nephrotoxic drugs (amphotericin in, lithium, demoslocyclin, mannitol). The reason lies in reducing the sensitivity of the renal channel receptors to the vasopressin. The clinical manifestations of the disease are the same, and the diagnosis is verified by the absence of a decrease in the diurea rate when the ADG is introduced.

Sodium deficiency.

The reasons for the lack of sodium can be either its excessive selection, or insufficient receipt. Selection, in turn, can occur through the kidneys, intestines and skin.

Causes of sodium deficiency:

1. Losses through the kidneys

Polyuric phase OPN;

Application of diuretics

Mineralocorticoid deficiency

Osmodiorez (for example, with diabetes mellitus)

2. Losses through the skin

Dermatitis;

Mukobovysidosis.

3. Losses through the intestines

Intestinal obstruction, peritonitis.

4. Losses of liquid rich in salts refundable by baking solutions (profuse diarrhea with a 5% glucose solution compensation).

Sodium can be lost in the composition of hypo-or isotonic fluid. In both cases, there is a decrease in the volume of extracellular space, which leads to the irritation of the voltoreceptors and the allocation of aldosterone. Increased sodium delay causes an increase in the secretion of protons into the lumen of the Netron Canal and the reabsorption of bicarbonate ions (see Renal mechanisms of the KSHC regulation), i.e. Causes metabolic alkalosis.

When sodium loss, its plasma concentration does not reflect the total content in the body, since it depends on the accompanying water losses. So, it was lost in the composition of the hypotonic fluid, the plasma concentration will be higher than the norm, with losses in combination with water delay - below. Losses of equivalent sodium and water and water will not affect its content in plasma. The diagnosis of the predominance of water and sodium losses is set out in Table 2.

Table 2. Diagnosis of prevailing water losses or sodium

In the case of the prevalence of water loss, the osmolarity of the extracellular fluid increases, which causes the transition of water from cells in interstics and vessels. Therefore, clinical signs will be expressed less clearly.

The most typical case is the sodium loss in the composition of isotonic fluid (isotonic dehydration). Depending on the degree of dehydration of the extracellular sector, three degracted degrees are isolated in the clinical picture (Table 3).

Table 3: Clinical degree of dehydration degree.

Excess water.

Excess water is associated with disruption, i.e. renal failure. The ability of healthy kidneys to remove water is 20 ml / h, therefore, if their function is not impaired, excess water due to excess receipts is practically excluded. Clinical signs of water intoxication are due primarily to the edema of the brain. The danger of its occurrence occurs when sodium concentration is approaching to 120 mmol / l.