About Your Kidneys
You need your kidneys to live, just like you need your heart, lungs and liver. Learn about them and take steps to help keep them healthy.
What do my kidneys do?
The main job of the kidneys is to filter wastes and extra water out of your blood to make urine (pee). Every day your kidneys filter about 120 to 150 quarts of blood—that’s about 30 gallons— and sift out one to two quarts of extra water and waste products. This waste and extra water become urine (pee), which flows to your bladder through tubes called ureters. The bladder stores the urine (pee) before it is released through urination (peeing). The kidneys also do many other jobs that you need in order to live. Your kidneys:
- Control chemicals and fluid in your body
- Help control your blood pressure
- Help keep your bones healthy
- Help you make red blood cells
The wastes in your blood come from the breakdown of food and muscle tissue. After your body takes the nutrients that it needs from food, the wastes are sent to the blood. If the kidneys did not take out these wastes, they would build up in the blood and hurt the body.
Within the kidney, the filtering of wastes happens in tiny units inside the kidneys called nephrons. Each kidney has about 1 million nephrons. Inside the nephron a tiny blood vessel, called the glomerulus, has a membrane that keeps normal proteins and cells in the blood and lets extra wastes and fluid pass through. These waste materials and water go into the urinary system.
Where are my kidneys?
Most people are born with two kidneys. These are bean-shaped organs that are each about the size of a fist. Your kidneys are part of your urinary tract. They are located near the middle of the back, on either side of your spine, just below your rib cage. Each kidney is connected to your bladder by a thin tube called a ureter.
What is kidney disease?
Because your kidneys filter waste, regulate blood pressure, make red blood cells, and keep bones healthy, when your kidneys aren't working as well as they should, your overall health begins to decline. When your kidneys have been permanently damaged and aren't functioning as well as they should, it's called chronic kidney disease (CKD), or kidney disease for short. The damage to the kidneys from CKD can get worse over time. If the damage is very bad, your kidneys may stop working. This is called kidney failure. If your kidneys fail, you will need dialysis or a kidney transplant in order to live.
CKD can be caused by many different diseases. The most common causes of CKD are diabetes and high blood pressure. Some infections, inherited diseases and injuries can also cause CKD.
Kidney disease often has no symptoms. Testing is the only way to know how well your kidneys are working. If you're at risk, talk to your doctor about getting tested, and encourage your at-risk loved ones to do the same. Testing is simple: a blood test and a urine test. If kidney disease is found, when it's caught and treated early, it can often be stopped or slowed.
Learn more about kidney disease
Learn about other kidney problems
Learn more about kidney failure
Learn about tests for kidney disease