Kidneys are located at the rear of the abdominal cavity and on both sides of waist and at the rear of peritoneum. Each of them is 10-12 cm in length and 120-160 g in weight.
Adrenal glands secreting significant hormones for the blood are located at the top of bean-shaped kidneys. Filtering units in the kidneys are called as nephron. Nephron constituting the basic structure for the urine comprises of glomerulus where the blood is filtered and tubes. There are about one million of nephrons in each kidney.
Kidneys fulfill a number of functions simultaneously. Structure of kidneys develop to fulfill basic functions efficiently. Kidneys excrete waste and hazardous substances from the body via urine and maintain salt and water balance of the body and various minerals in the blood at a stabile level.