Most people are born with two kidneys which are bean shaped organs that are about the size of your fist. The kidneys are located on each side of the spine in the back of the abdomen just below your ribs.
During normal activities, the cells in the body produce waste products that need to be removed. This waste is picked up by the blood and carried to the kidneys, which are the body’s filtration system. In the kidneys, the waste products and excess water are cleaned out of the blood and combined into urine. Each day, about 200 quarts of blood travel through the kidneys and about 2 quarts of waste and water are removed.
In addition to cleaning out waste products, the kidneys have the important job of regulating the levels of certain chemicals in the blood including sodium, phosphorus, and potassium. As the blood is filtered, the kidneys measure the amounts of these chemicals and replace the correct amount of each one back into the bloodstream.
The kidneys also produce three key hormones which are used by the body as messengers to regulate certain functions. These hormones stimulate red blood cell production in the bone marrow, regulate blood pressure, and regulate vitamin D which is needed for healthy calcium levels in the bones.
Why people need kidney transplants
Kidneys that are injured in an accident or damaged by disease do not work as well as healthy kidneys. High blood pressure and diabetes are the two most common causes of kidney disease. In people with diabetes, excess glucose (sugar) in the blood can damage the filters in the kidneys that trap and remove waste products. High blood pressure can damage the very small blood vessels inside the kidneys which limits the flow of blood through the filters.
Doctors measure kidney function by testing the blood to see how well the kidneys are doing their job of filtering out waste products. Kidney function of 25 percent or less can cause serious health issues because waste products are not being completely cleaned from the blood.