Water Metabolism - an overview | Care Pharma Topics

 Water and Electrolytes

WATER METABOLISM

Distribution of body water : Water content of the body is about 60 to 70% of body weight. Water present in the body may be classified as -

• Intracellular water - about 50% of body weight

• Extracellular water - about 20% of body weight

Extracellular water is further classified as -

• Plasma - 7.5% of body weight

• Interstitial fluid - 20% of body weight

• Connective tissue (bones and cartilage) - 15% of body weight

• Transcellular fluids (CSF, endolymph etc.) - 5% of body weight

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Functions of body water :

• It acts as a solvent for cellular components

• It acts as a carrier for nutrition and waste products

• It is a regulator of body temperature

• It regulates electrolyte balance and osmotic pressure

• It lubricates joints and membranes (like pleura and peritoneum)

Water balance : In health, a balance is maintained between intake and output of water. This regulatory mechanism prevents -

• Accumulation of water leading to edema

• Loss of water leading to dehydration. This regulatory mechanism is further influenced by hormones like ADH and aldeosterone

Water gain : Body gains water through the following sources -

• Drinking of water and beverages

• Water present in foods

• Water formed by oxidation of foods

Water loss : Body loses water through the following routes -

• Through lungs by respiration

• Through skin by respiration

• Excretion through urine and faeces

 Body is said to maintain water balance when water gain is equal to water loss.

Water intake ml per day

drinking - 1200

water in food - 1000

oxidation of food - 300

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total amount - 2500

Water lost ml per day

lungs - 300

skin - 600

urine - 1400

faeces - 200

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total amount - 2500

WATER INTOXICATION

 It is the opposite of dehydration. It is caused by excessive retention of water in the body. It is caused by -

• Renal failure

• Excessive administration of IV fluids

• Hyper secretion of ADH or aldosterone

 The symptoms of water intoxication are headache, nausea, incoordination of movements and muscle weakness.