Chronic Kidney Disease (CKD) affects 26 million Americans. Early detection can help to prevent progression of the disease – which ultimately can lead to kidney failure and death. However, early detection can be difficult because the signs and symptoms of kidney disease, and even acute kidney failure, are often overlooked.
When it comes to kidney disease or kidney cancer, any well-informed patient must understand how the kidneys work.
The following is a reprint of information compiled and created by the National Kidney and Urologic Diseases Information Clearinghouse, a service of the National Institute of Health.
What do the kidneys do?
The kidneys remove wastes and extra water from the blood to form urine. Urine flows from the kidneys to the bladder through the ureters.
Your kidneys are bean-shaped organs, each about the size of your fist. They are located near the middle of your back, just below the rib cage. The kidneys are sophisticated reprocessing machines. Every day, your kidneys process about 200 quarts of blood to sift out about 2 quarts of waste products and extra water. The waste and extra water become urine, which flows to your bladder through tubes called ureters. Your bladder stores urine until you go to the bathroom.
The wastes in your blood come from the normal breakdown of active tissues and from the food you eat. Your body uses food for energy and self-repair. After your body has taken what it needs from the food, waste is sent to the blood. If your kidneys did not remove these wastes, the wastes would build up in the blood and damage your body.
The actual filtering occurs in tiny units inside your kidneys called nephrons. Every kidney has about a million nephrons. In the nephron, a glomerulus—which is a tiny blood vessel, or capillary—intertwines with a tiny urine-collecting tube called a tubule. A complicated chemical exchange takes place, as waste materials and water leave your blood and enter your urinary system.