- The document discusses water, electrolyte, and acid-base balance in the human body. It covers topics like fluid compartments, regulation of water balance, electrolyte balance, and hormonal control. - Key points include that total body water is about 60% of body weight and is distributed in intracellular and extracellular compartments. Water balance is regulated by thirst, ADH, and urination. Electrolyte levels like sodium, potassium, and calcium are also tightly controlled. - Hormones like ADH, aldosterone, renin-angiotensin system, and atrial natriuretic factor help regulate water and electrolyte levels in response to changes in blood volume, pressure, and os

1. Water, Electrolyte, and Acid-Base Balance

5. FLUID BALANCE 40% 50% OVER 60 40-50% 50-60% 40-60 50% 60% 18-40 55% 65% UNDER 18 FEMALE MALE AGE TOTAL BODY WATER (AS PERCENTAGE OF BODY WEIGHT) IN RELATION TO AGE AND SEX

7. Function of Water : Most of cellular activities are performed in water solutions.

14. 16% TBW 40% TBW 4% TBW - makes up ~60% of total body weight (TBW) - distributed in three fluid compartments. Body Fluid

15. 16% TBW 40% TBW 4% TBW Fluid is continually exchanged between the three compartments.

17. 16% TBW 40% TBW 4% TBW - not affected by electrolyte concentrations - Edema = water accumulation in tissue fluid Exchange between Blood & Tissue Fluid

19. Water Gain Water is gained from three sources. 1) food (~700 ml/day) 2) drink – voluntarily controlled 3) metabolic water (200 ml/day) --- produced as a byproduct of aerobic respiration

20. Routes of water loss 1) Urine – obligatory (unavoidable) and physiologically regulated, minimum 400 ml/day 2) Feces -- obligatory water loss, ~200 ml/day 3) Breath – obligatory water loss, ~300 ml/day 4) Cutaneous evaporation -- obligatory water loss, ~400 ml/day 5) Sweat – for releasing heat, varies significantly

21. Regulation of Water Intake - governed by thirst.  blood volume and  osmolarity  peripheral volume sensors central osmoreceptors  hypothalamus  thirst felt

23. Regulation of Water Output - The only physiological control is through variations in urine volume. - urine volume regulated by hormones

25. HORMONAL MECHANISMS Helps to regulate blood composition and blood volume.

28. 1) ADH dehydration   blood volume and/or  osmolality  hypothalamic receptors / peripheral volume sensors  posterior pituitary to release ADH   H 2 O reabsorption  Water retention

30. 2) Atrial Natriuretic Factor  blood volume =↑ BP  atrial volume sensors  atria to release ANF  inhibits Na + and H 2 O reabsorption   water output = ↓ BP

38. HORMONE REGULATION: Insulin and Epinephrine = cause K+ and phosphate to move from extracellular fluid into cells Parathyroid hormone = cause Ca++ and phosphate to move from bone to extracellular fluid Calcitonin = moves calcium to bones ELECTROLYTE BALANCE

39. Electrolytes = small ions that carry charges

41. Na + K + Ca ++ Cl - PO 4 --- Distribution of Electrolytes Cell Extracellular space

43. Ions - 285 – 295 mosm/kg Osmolality 24 mg = 1 mmol 1.8 – 3.0 mg/dL Magnesium (Mg 2+ ) 31 mg = 1 mmol 2.5 – 4.5 mg/dL Phosphorus 40 mg = 1 mmol 8.5 – 10.5 mg/dL Calcium (Ca 2+ ) 61 mg = 1 meq 22 – 26 meq/L Bicarbonate (HCO 3 - ) 35 mg = 1 meq 98 – 107 meq/L Chloride (Cl - ) 39 mg = 1 meq 3.5 – 5.0 meq/L Potassium (K + ) 23 mg = 1 meq 135 – 145 meq/L Sodium (Na + ) Mass Conversion Normal Plasma Values NORMAL VALUES AND MASS CONVERSION FACTORS

49. 3) ADH increases water reabsorption in kidneys  water retention  dilute plasma Na + plasma Na + H 2 O

59. Hyponatremia Hypernatremia

66. Abnormal Concentration of Potassium Ions

67. HYPERKALEMIA

70. Abnormal Concentration of Potassium Ions

71. HYPOKALEMIA

79. Muscle Contraction

82. Dynamics of Calcium Ca ++ plasma Ca ++ Ca ++ Ca ++

84. 2) calcitonin (secreted by C cells in thyroid gland):

85. 2) calcitonin (secreted by C cells in thyroid gland): depositing Ca ++ in bones Respond when high Ca ++ in the blood plasma Ca ++ Ca ++

86. 3) calcitrol ( derivative of vitamin D): - enhancing intestinal absorption of Ca ++ from food plasma Ca ++ Ca ++ Ca ++

92. (+) Chovstek’s Trousseaus Sign

113. ACID-BASE BALANCE

114. Acid An acid is any chemical that releases H + in solution. Base A base is any chemical that accepts H + .

115. pH is the negative logarithm of H + concentration, and an indicator of acidity. pH = - log [H + ] Example: [H + ] = 0.1  M = 10 –7 M

116. Normal functions of proteins (especially enzymes) heavily depend on an optimal pH. pH7.35-pH7.45

117. Regulation of acid-base balance 1) Chemical Buffers 2) Respiratory Control of pH 3) Renal Control of pH

122. 3) The Protein Buffer There are three major buffers in body fluid. 1) The Bicarbonate (HCO 3 - ) Buffer 2) The Phosphate Buffer Chemical Buffers