Function of kidney

• Kidney


  Important for homeostasis in the water balance of the body
• If you are short of water

  Your kidney concentrates it, your body produces very little urine
• If you drink too much

  Your kidney produces lots of dilute urine to get rid of excess
• Kidney


  • Removes excess mineral ions and excretes them in urine
• Kidney filters blood


  1. Glucose, minerals, water filtered out of blood into kidney

  2. Blood cells and large proteins too big to leave blood in filtering process

  3. All blood in body passes through kidney and is filtered

  4. All the filtered substances are reabsorbed back into blood by osmosis, diffusion and active transport

  5. The amount of water reabsorbed back into blood is controlled by a sensitive feedback mechanism to maintain water balance
• Kidney tubules


  Where reabsorption of water and minerals takes place
• Water balance regulation


  1. Receptors in brain detect concentration of solutes in blood plasma

  2. If blood too concentrated, pituitary gland releases ADH hormone

  3. ADH causes kidney tubules to reabsorb more water

  4. If blood too dilute, less ADH is released so less water reabsorbed in kidney tubules