The urinary tract is made up of the kidneys, the ureters, the bladder and the urethra. Each plays an important role in helping your body to eliminate waste products in the form of urine. The main job of the kidneys is to remove wastes from the blood and return the cleaned blood back to the body. The ureters are tubes that carry the waste products, as urine, from the kidneys to the bladder. The bladder stores urine until it passes out of the body, when you urinate, through a tube called the urethra. ■ What is a urinary tract infection? A urinary tract infection (UTI) is an inflammation usually caused by bacteria (or germs) attacking the kidneys, ureters, bladder or urethra. Under normal circumstances the urinary tract is sterile, or free of bacteria.