The tube that carries URINE from the kidney (see KIDNEYS) to the URINARY BLADDER. There are two ureters, one for each kidney, and they originate from the kidney pelvis and track for 25–30 cm (10–12 inches) through the loins and pelvis. They open by a narrow slit into the base of the bladder. The lower end of the ureter pierces the wall of the bladder so obliquely (lying embedded in the wall for about 21 mm) that, although urine runs freely into the bladder, it is prevented from returning up the ureter as the bladder becomes distended.