This will tell about water balance, electrolyte balance, acid base balance, water input and water output, major routes of water excretion

1. Water and mineral metabolism
Dr. Kuldeep Bansod

2. The acid-base homeostasis speaks:
We maintain the pH at 7.4!
Regulate by buffers, lungs and kidney

3. You will be able to . . .
1. Explain the distribution of water in the body.
2. Describe the importance of water balance and organs involved
in it.
3. Define dehydration and give its symptoms, causes and
treatment.
4. Define electrolyte balance, acid-base balance.
5. How body maintains the normal pH.
6. State the various disease mechanism of changes in blood pH.

4. Kidney functions
Maintenance of
homeostasis
•Regulate
water,
electrolyte and
acid-base
balance
Excretion of
metabolic waste
•End products
of protein &
nucleic acid
metabolism are
eliminated
Retention of
vital substances
•Reabsorb &
retain several
substances of
biochemical
importance
Hormonal
functions
•Erythropoietin:
stimulates Hb
synthesis and
erythrocytes
formation
•Calcitriol: active form of Vit. D if produced
•Renin: Proteolytic enzyme, stimulates formation of Angiotensin II
aldosterone production regulate electrolyte balance

5. Water balance
Solvent of life

6. Water functions
● Provides aqueous medium to the organism which is
essential for the various biochemical reactions to occur
● Directly participates as a reactant in several
metabolic reactions
● Serves as a vehicle for transport of solutes
● Regulate body temperature

7. Distribution of water
● 70 kg of person will have 42 L of water

8. Water turnover and balance
Exogenous
• Ingested water and beverages, water
content of solid foods
• Controlled by climate and thirst
center
• Increase in osmolarity of plasma
causes increased water intake by
stimulating thirst center
Endogenous
• Metabolic water produced within the
body by oxidation of foods (0.3-0.35
L/day)
• 1 g carbohydrate 0.6 mL water
• 1 g proteins  0.4 mL water
• 1 g fat  1.1 mL water
Water intake
About 125 mL of water is generated for 1000 Cal consumed

9. Urine
• Major route for
water loss
• Output is 1-2
L/day
• It is essential as
medium to
eliminate the
waste products
• Hormones regulate
urine production
Skin
• Loss
perspiration
• Depends on
atmospheric temp
and humidity
• Fever increases
water loss through
skin
• 1°C ↑ in body
temp 15% ↑
loss of water
Lung
• Respiration
water lost through
expired air
• Hot climates/
fever ↑ water
loss through lungs
Feces
• Most water is
reabsorbed from
intestine
• Lost through feces
• Fecal loss is
tremendously
increased in
diarrhea
Water turnover and balance
Water Output
Diabetes insipidus is a disorder characterized by the deficiency of ADH
which results in a n increased loss of water from the body.

10. Body water
42000 mL
Drinking water
1500 mL
Food stuffs
700 mL
Metabolic water
300 mL
Water turnover and balance
Water Output
Water intake
Urine
1500 mL
Skin
450 mL
Lungs
400 mL
Feces
150 mL
2500 mL
2500 mL

11. Electrolyte balance
Electrolytes dissociate in solution and exist as ions

12. Composition of electrolytes in the body fluids (Expressed as mEq/l)
● Na+  principal extracellular cation
Extracellular fluid Intracellular fluid
Cations Anions Cations Anions
Na+ 142 Cl- 103 K+ 150 HPO4
2- 140
K+ 5 HCO3
- 27 Na+ 10 HCO3
- 10
Ca2+ 5 HPO4
2- 2 Mg2+ 40 Cl- 2
Mg2+ 3 SO4
2- 1 Ca2+ 2 SO4
2- 5
Proteins 16 Proteins 40
Organic acids 6 Organic acids 5
155 155 202 202
● K+ principal intracellular cation

13. Osmolarity and osmolality of body fluids
Osmolarity
Osmolality
• The number of
moles (or millimoles)
per liter of solution
• The number of
moles (or millimoles)
per kg of solution

14. Osmolality of plasma
● It is in the range of 285-295 milliosmoles/kg
● Generally measured by osmometer
● Plasma osmolality can be computed as
2(Na +) + 2(K +) + Urea + Glucose
● Factor 2 is used for NA + and K + to account for the associated
anion concentration.
● Plasma Na + is most abundant contributor of osmolality, the above
calculation simplified to
Plasma osmolality = 2 X Plasma Na+
● This true when the glucose and urea are in normal range

15. Regulation of electrolyte balance
● Aldosterone
● ADH
● Renin-angiotensin
● Atrial natriuretic factor
○ Secreted by right atrium
○ ↑ Na+ excretion

16. Dehydration
● It is a negative water balance leading to a decrease in
water content of the body.
Water Output
Water intake
● Deprivation of water
and electrolytes
● Loss of water alone

17. Causes of dehydration
Diarrhea Vomiting Fever
Excessive swatting Increased urination Excessive exercise
Excessive burns
Kidney disease

18. Characteristic features of dehydration
ECF volume is decreased  rise in electrolyte conc and osmotic pressure
Water drawn from ICF  shrunken cells and disturbed metabolism
ADH secretion increased↑ water retention urine volume low
Plasma protein and blood urea concentration increased
Water depletion often accompanied by loss of electrolytes (Na+, K+, etc.)
Symptoms: ↑ pulse rate, ↓ BP, sunken eyeballs, ↓ skin turgor, lethargy, confusion and coma.

19. Treatment of dehydration
● Intake of plenty of water
● If not possible orally then 5% glucose
● If dehydration accompanied with electrolytes loss then same
should be administered orally or intravenously
● ORS should administered
● Carefully monitor the water and electrolyte status of the body

20. Osmotic imbalance and dehydration in cholera
● Transmitted through water and foods
● Bacterium vibrio cholerae
● Bacterium produces toxin stimulates intestinal cells to secrete ions
into intestinal lumen suck water into lumen watery diarrhea
● If not treated in time patient die due to dehydration
● Oral rehydration therapy (ORT) commonly used

21. Overhydration (water intoxication)
● Excessive retention of water in the body
● Reasons: excessive water intake, salt free fluids, renal failure,
overproduction of ADH
● Clinical symptoms: headache, lethargy, and convulsions
● Treatment: stoppage of water intake and administration of hypertonic
saline

22. Acid-base balance
Normal blood pH: 7.35-7.45
Erythrocyte pH: 7.2
Skeletal muscle pH: 6
H2CO3 H+ + HCO3
-

23. Thank you
Dr. Kuldeep Bansod
9404485404
kuldeepbansod@gmail.com
KuldeepBansodEduPharma