How Kidneys Work
Learn about the important role of kidneys
Think of your kidneys as a complex waste treatment plant for your body. As you eat and drink, your body takes what it needs for nutrients, energy, and self-repair. Whatever it doesn’t use become wastes that end up in your bloodstream. Your kidneys filter out these “leftovers” and water from your blood. The key job of the kidneys is to maintain an internal balance of water and chemicals. This is called homeostasis.
Kidneys are masters of waste removal
1. Your kidneys contain a million tiny filtering centers called nephrons.
2. Inside each nephron is a glomerulus, a special strainer that keeps blood cells and needed substances in—and extra fluid and wastes out. With every heartbeat, blood is pushed through your body.
3. Blood enters the kidney through the renal artery.
4. The kidneys filters out extra fluid and wastes. Drop by drop, urine is made. Urine travels to the bladder through a tube called a ureter. It is removed from your body through urination.
Healthy kidneys clean the blood 24 hours a day and filter out about 2 quarts of extra fluid and wastes every day.
What happens when the kidneys aren’t working well?
Learn signs and symptoms of chronic kidney disease and what you can do to help keep kidneys working over a longer period of time.
The kidneys role with hormones
Hormones are substances made in one part of the body that act on another part. The kidneys make and release hormones that control blood pressure and other functions.
Kidneys produce and release three hormones:
- Renin helps control your blood pressure and regulates how much sodium (salt) and fluid the body saves.
- Erythropoietin tells the bone marrow to make new red blood cells
- Calcitriol is the active form of Vitamin D that helps the body absorb calcium from food.
Making and releasing hormones is another important way the kidneys work to keep your body healthy and working.