The bladder is a hollow organ in the lower abdomen. It stores urine, the liquid waste produced by the kidneys. Urine passes from each kidney into the bladder through a tube called a ureter.

An outer layer of muscle surrounds the inner lining of the bladder. When the bladder is full, the muscles in the bladder wall can tighten to allow urination. Urine leaves the bladder through another tube, the urethra.

Glossary Terms

The area of the body that contains the pancreas, stomach, intestines, liver, gallbladder, and other organs.

The tube that carries urine from the kidney to the bladder.

The tube through which urine leaves the body. It empties urine from the bladder.

Fluid containing water and waste products. Urine is made by the kidneys, stored in the bladder, and leaves the body through the urethra.