Q.8 Describe osmoregulatory function of kidney.
Answer:
Osmoregulation
Osmoregulation is defined as the regulation of the concentration of water and salts in blood and other body fluids. Kidneys play an important role in osmoregulation by regulating the water contents of blood. It is an important process as excessive loss of water concentrates the body fluids whereas excess intake of water dilutes them.
Dilute urine
When there is excess water in body fluids, kidneys form dilute (hypotonic) urine. For this purpose, kidneys filter more water from glomerular capillaries into Bowman’s capsule. Similarly less water is reabsorbed and abundant dilute urine is produced. It brings down the volume of body fluids to normal.
Concentrated urine
When there is shortage of water in body fluids, kidneys filter less water from glomerular capillaries and the rate of reabsorption of water is increased. Less filtration and more reabsorption produce small amount of concentrated (hypertonic) urine. It increases the volume of body fluids to normal.
This whole process is under hormonal control.