Kidney filters out waste products from blood stream. Normally 200 litres of water are filtered through the kidney daily and only about 2 liters are passed as urine.

Usually, there are two kidneys in each one of us. They are bean shaped and weigh about 150gms and are 12 cm x 5 cms in size. They are located in the middle of the back, just below the rib cage. Each kidney is made up of small, complex units called nephrons. The two kidneys contain about two million nephrons. The nephrons work continuously to filter out waste products from the blood stream, all of which come from the food that one eats and the fluid that one drinks. The kidney also regulates the concentration of most of the constituents of body fluids.

They also retain certain substances that are needed by the body. In addition, the kidneys stimulate the body to produce red blood cells, regulate blood pressure, keep bones healthy by converting inactive Vitamin D to its active form and maintain the water and pH (acidity / alkalinity) balance of the body.