The five main jobs of kidneys, according to the National Kidney Foundation:
- Remove wastes and extra fluid
Your kidneys act as a filter to remove wastes and extra fluid from your body. They filter about 200 quarts of blood each day to make about 1 to 2 quarts of urine.
- Control blood pressure
Your kidneys need pressure to work properly. They can seek more if the pressure seems too low or can try to lower pressure that seems too high by controlling fluid levels and making a hormone that causes blood vessels to constrict.
- Make red blood cells
Kidneys make a hormone called erythropoietin, which tells bone marrow to make red blood cells. These red blood cells carry oxygen throughout the body. Damaged kidneys don’t make enough of the hormone, and that prevents bone marrow from making enough red blood cells, which can cause anemia.
- Keep bones healthy
The kidneys convert vitamin D into an active form the body needs to absorb calcium and phosphorus, important minerals for keeping bones strong. Kidneys also balance the minerals so the right amounts are in your body.
- Control pH levels
A pH level is a measure of acid and base. Kidneys help maintain a healthy balance of the chemicals that control acid levels. Everyday processes from walking to digesting food create acid as a byproduct. Kidneys help determine the pH of your body and blood, and adjust it if it’s too acidic or basic.
While the kidneys might sound like one big filter, they in truth are each made up of about a million filtering units called nephrons. In the nephron, tiny blood vessels called capillaries intertwine with tiny, urine-carrying tubes called tubules. It’s a complicated chemical exchange that allows waste and water to be filtered out and other hormones and chemicals to be created or metered out to keep your body in balance from head to toe.
Healthy kidneys like a healthy body. Because many other diseases can affect the kidney, it’s important to eat healthy, exercise regularly, not smoke, and be careful with over-the-counter pain relievers because prolonged use can cause kidney damage.