PHYSIOLOGY OF WATER-ELECTROLYTES BALANCE

1. PHYSIOLOGY OF WATER-ELECTROLYTES BALANCE

3. Total body water in adult human • 60-70 %

4. It consists of • Extra cellular water – 20 % • Intracellular water – 40 % • Extra cellular water consists of • Intravascular water or blood plasma – 5 % • Interstitial water – 15 %

7. Function of body fluids • 1. Facilitate the transport of nutrients, hormones, proteins, other molecules into the cells • 2. Aid in the removal of cellular metabolic waste products • 3. Provide the medium in which cellular metabolism takes place

8. Function of body fluids • 4. Regulate body temperature • 5. Provide lubrication of musculoskeletal joints • 6. Act as a component in all body cavities (pericardial, pleural, spinal, peritoneal fluid – 1 % of TBF)

9. Peculiarities • Fatty tissue contains less water than muscle. • Older adults tend to lose muscle mass as they age, thereby decreasing the percent of body water • Infants have a higher percentage of body weight as water

10. Electrolyte composition of body fluids • The primary body electrolytes are sodium, potassium, chloride, calcium, magnesium, phosphorus, hydrogen, bicarbonate. • Major ICF electrolytes are potassium and magnesium, and phosphorus. • Major ECF electrolytes are sodium and chloride, and bicarbonate.

11. Daily water balance • Enters to body = 1,5-2,5 l • With food • With drinks • Cellular metabolism • Excreted with lungs (0.5 l), skin (0.5-0.6 l), GIT (0.1-0.2 l), kidneys (0.8-1.5 l)

12. Organs, which maintaining water- salts homeostasis • Lungs • Heart • Pituitary • Adrenal cortex • Para thyroids • Kidneys • Blood vessels

13. Renal regulation • Produce renin, which activates angiotensin I, which converted to angiotensin II (power vasoconstrictor), which increase glomerular filtration and urine output (if serum sodium is low with normal). And opposite reaction is in the case of high serum sodium.

14. Endocrine regulation • In the hypothalamus is present the primary regulators of water - thirst center. • In the posterior hypothalamus is present the osmoreceptors which is respond to changes in ECF osmolarity (increases of ECF osmolarity helps to secretes vassopressine - ADH). • Adrenal glands produce aldosterone. • Parathyroid secretes parathyroid hormones.

15. Cardiovascular regulation • The cardiovascular system regulates fluid volume, pressure sensors, and atrial natriuretic factor.

16. Gastrointestinal regulation • Secretion and absorption of fluids.

17. Pulmonary regulation • The elimination process and water loss with hyperventilation and mechanical ventilation.

18. Role of electrolytes • 1. Its conduct electricity across cell membranes; they are needed for life processes to occur. • 2. Maintain osmolality of body fluid compartments • 3. Regulate balance of acids and bases • 4. Aid in neurological and neuromuscular conduction

19. Electrolyte balance • 1. For a homeostatic condition to exist, equal amounts of anions and cations must be present on either side of the cell membrane. • 2. They can move from one to another side. • 3. Extra cellular electrolytes are found in the interstitial and intravascular fluids where there is a balance of cations and anions.

20. Regulation of electrolytes • 1. Kidneys • 2. Endocrine system • 3. Gastrointestinal tract

21. Meaning of main ions • Sodium (135-150 mmol/L) • Potassium (3.8-5.2 mmol/L) • Chloride (98-105 mmol/L) • Calcium (2.35-2.75 mmol/L) • Magnesium (0.70-1.1 mmol/L)

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