Your urinary tract is the body system involved in the formation and excretion of urine. The kidneys filter out waste products from the blood. These waste products in combination with water are urine. The urine passes out of the kidneys through two narrow, muscular tubes called ureters. The ureters empty the urine into the bladder, and the urine is then excreted from the body through a tubelike structure called the urethra.
Source: AMA's Current Procedural Terminology, Revised 1998 Edition. CPT is a trademark of the American Medical Association.