Kidneys act as sophisticated filters to remove organic waste products from the blood and then excrete these waste products, along with excess salt and water, from the body through the urine. We are normally born with two kidneys located on either side of the lower back just below the rib cage. The kidneys are such incredibly well-functioning organs that only one normal, healthy kidney is required for good health. Each kidney is 4-5 inches long, weighs about 6 ounces, and contains about 1 million nephrons. Nephrons are the working units of the kidney that are responsible for waste removal. As part of our normal aging process, kidney function diminishes as the number of functional nephrons is reduced.
The kidneys play a role in controlling the acid-base balance in the body as well as helping to control blood pressure. Another function of the kidneys is to produce hormones such as erythropoietin, which regulates the production and release of red blood cells from the bone marrow.
Each day, the kidneys filter approximately 200 quarts of blood, producing about 2 quarts of waste products and water. These waste products and excess water pass from the kidneys through the ureters (tubes that connect the kidneys to the bladder) and into the bladder where they are briefly stored before being eliminated as liquid waste via the urine. Filtered waste products include the normal organic material from the breakdown of cells, proteins, excess food by-products, and various minerals, as well as the individual waste excretions from cells of the body. Alcohol, drugs, excess protein, minerals, and ingested toxins are also filtered by the kidneys. These toxic agents can have a dramatic, destructive effect on the health and function of the kidneys.