The bean shaped kidneys located below the rib cage on either side of the spine help to filter the blood usually half a cup every minute. Removing wastes, extra fluids and flushing out toxins from the body, kidneys produce urine that is stored in the bladder. Maintaining a healthy balance of salts, water and minerals in the body, they also remove acid produced by various body cells creating an equilibrium for muscles, nerves and other tissues to function properly.