The Urinary System is the system of production, storage and elimination of urine. It removes wastes from the blood and helps to maintain water and electrolyte balance; it keeps the internal environment of the body clean. The whole system includes the kidneys which form urine and control its concentration; the ureters which connect the kidneys to the bladder; the bladder which stores the urine before it is eliminated from the body; the urethra which is a tube that connects the bladder to the external genitalia for elimination from the body; and the sphincter muscles which control the elimination of urine from the body.