Kidney: Structures and Functions

Your Kidneys and How They Work.

The kidneys are vital organs that have many functions. It keeps our body clean of toxins and balance chemicals in the body. They also help maintain normal blood pressure and maintain the normal number of red blood cells. It is important to understand how your kidneys work so that you will know how to keep them healthy.

The kidneys are two bean-shaped organs located below the ribs toward the middle of the back, one on each side of the spine. They are about the size of your fist. The right kidney is slightly lower than the left because the liver displaces it downward. (See figure on the right. Image Credit: National Kidney and Urologic Diseases Information Clearinghouse-NKUDIC) The kidneys are considered as the primary organs of the urinary system. They process about 200 quarts of blood each day and sifts out about 2 quarts of extra water and wastes. The waste products and extra water comprises the urine, which flows through narrow tubes called the ureters. From the ureters, the urine will flow to the urinary bladder where it is stored until you release it by urinating.

Inside each kidney are about 1 million tiny structures called the nephrons. Each nephron consists of the glomerulus—where actual sifting or filtering of blood occurs—and the tubule. The tubule is the tiny urine-collecting tube of the nephron.(See figure on the right. Image Credit: NKUDIC)

At first, the tubules receive a combination of waste materials and chemicals that your body can still use. Some of these chemicals include sodium, phosphorus, and potassium. If your body is lacking any of these chemicals, your kidneys can release them back to the blood to maintain their normal levels. If these chemicals are in excess, the kidneys will release it to become a part of the urine. This is how the kidneys maintain the normal levels of chemicals inside your body. The right balance is necessary for life, but excess levels can be harmful too.

The kidneys also release important hormones that help to maintain balance in the body. It releases erythropoietin, renin, and calcitriol.

• Erythropoietin (eh-RITH-ro-POY-eh-tin) or EPO, stimulates the bone marrow to make red blood cells
  
• Renin (REE-nin) regulates blood pressure
  
• Calcitriol (kal-suh-TRY-ul), the active form of vitamin D, helps maintain calcium for bones and for normal chemical balance in the body
  

If the kidneys fail to function, a condition called renal failure, this would cause an excessive build up of toxins in the body. You will need dialysis to rid of these toxins.

This article was originally published at the Kidney and Kidney Stones web site.


Source:D.K. Mangusan Jr, PTRP (2008). Kidney: Structures and Functions. Kidney and Kidney Stones (KKS). Web Url: http://www.kidney-and-kidney-stones.blogspot.com/2008/05/kidney-structures-and-functions.html. Retrieved June 2008

Image Credit: National Institute of Diabetes and Digestive and Kidney Diseases. National Institutes of Health.