The bladder is a hollow, globe-shaped muscular organ that collects and stores urine. It is located in the lower part of the pelvis.
The interior of the bladder is covered with a lining called the urothelium, which prevents urine from filtering into the body once again and keeping it contained in the bladder.
Urine is produced by the kidneys and travels to the bladder through tubes called ureters. The bladder stores urine. Urine is made up of water and waste products that the body doesn't need.
When it is full, the bladder sends messages to the brain so that it feels the need to urinate. The muscle contracts and the bladder expels the urine from the body through the urethra.