The kidneys are two bean-shaped organs located on either side of the spine, at the small of the back. The kidneys filter wastes from the blood and help balance water, salt, and mineral levels in the blood.

Wastes filtered out of the blood are carried out of the body as urine. Urine flows through tubes (ureters) to the bladder, where it is stored until a person is ready to urinate. The waste and urine then leave the bladder and exit the body through a tube called the urethra.