Your kidneys are bean-shaped organs found below the rib cage on either side of the spine. Each one is roughly the size of your fist and weighs 1/3 of a pound. They filter 30-40 gallons of blood per day. They also create urine which contains excess waste, electrolytes and water.

Blood flow to the kidneys is important. They receive 20% of the blood pumped by the heart every minute. Blood travels from the heart through the aorta, which delivers a branch to each kidney. The kidneys clean this blood and extra waste is excreted as urine.

Urine flows through two tubes called ureters into the bladder. The bladder is a muscle which remains relaxed until it fills up with urine. Once filled, the bladder sends electrical signals to the brain asking to be emptied.