The urinary tract is a group of organs that work together to remove urine from the body. It includes the bladder, two ureters, and the urethra. Urine is made in the kidneys and travels to the bladder by two long tubes called ureters. The bladder is a hollow organ located in the pelvis. The purpose of the bladder is to store urine and then to release it out of the body through a tube called the urethra.
The inside of the urinary tract is lined by cells called urothelial cells. These cells form a barrier called the urothelium. The tissue directly below the urothelium is called the lamina propria. The inside of the ureters and urethra are also lined by urothelial cells.