Maintaining Water and Nitrogen balance in the body

• Water leaves the body via the lungs during exhalation
• Water, Ions and Urea are lost from the skin in sweat
• There is no control over Water, Ion and Urea loss by skin or lungs
• Excess water, ions and urea are removed via the kidneys in the urine
• If body cells lose or gain too much water by osmosis they do not function efficiently
• The digestion of proteins from the diet results in excess amino acids
• In the liver these amino acids are deaminated to form ammonia
• Ammonia is toxic and so it is immediately converted to urea for safe excretion