The kidneys are 2 bean-shaped organs. Each is about the size of a fist. You have 1 on either side of your spine in the middle-to-lower back. They have 2 main roles:

• Filter waste from the blood and make urine;
• Make the hormone erythropoietin that controls the production of red blood cells in the bone marrow;
• Help regulate blood pressure.

Most people are born with 2 kidneys, but you can survive with only 1. You can also survive with no kidneys. People with no kidneys or kidneys that don’t work survive with the help of dialysis. Dialysis uses a special machine to filter the blood.