Question

Describe the role the kidneys play in regulating the osmotic pressure of the fluids.

Answer 1

Osmotic pressure

1. The osmotic pressure of a fluid is defined as the minimum pressure required to be applied to the fluid to prevent the inflow of its solvent across a semi-permeable membrane.

Osmoregulation

1. Kidneys regulate the osmotic pressure of the fluids in a mammal by the process of osmoregulation. It helps in maintaining the levels of water and various ions in our bodies.
2. When the blood is dilute, water moves from the blood to the glomerular filtrate producing dilute urine. Otherwise, the cells will undergo oedema.
3. When the blood is concentrated, water moves back from the glomerular filtrate to the blood, producing concentrated urine. Otherwise, the cells will undergo dehydration.
4. The reabsorption of water in the kidneys is controlled by the antidiuretic hormone.
5. Dilute blood inhibits the synthesis of ADH thereby producing a large amount of dilute urine.
6. Concentrated blood with less amount of water stimulates the release of ADH thus initiating reabsorption of water in the nephrons thereby resulting in the production of concentrated urine.
7. The renal tubule is constantly reabsorbing various solutes from the glomerular filtrate back into the blood. This helps in maintaining the osmotic pressure of body fluids.