The kidneys are two bean-shaped organs, each about the size of a fist. They are located just below the rib cage, one on each side of the spine. Every day, the two kidneys filter blood to produce urine, composed of wastes and extra fluid. The urine flows from the kidneys to the bladder through two thin tubes of muscle called ureters, one on each side of the bladder. The bladder stores urine. The muscles of the bladder wall remain relaxed while the bladder fills with urine. As the bladder fills to capacity, signals sent to the brain tell a person to find a toilet soon. When the bladder empties, urine flows out of the body through a tube called the urethra, located at the bottom of the bladder. In men the urethra is long, while in women it is short.
Why are the kidneys important?
The kidneys are important because they keep the composition, or makeup, of the blood stable, which lets the body function. They:
How do the kidneys work?
- Prevent the build-up of wastes and extra fluid in the body
- Keep levels of electrolytes stable, such as sodium, potassium, and phosphate
- Make hormones that help regulate blood pressure, make red blood cells and bones stay strong
The kidney is not one large filter. Each kidney is made up of about a million filtering units called nephrons. Each nephron filters a small amount of blood. The nephron includes a filter, called the glomerulus, and a tubule. The nephrons work through a two-step process. The glomerulus lets fluid and waste products pass through it however, it prevents blood cells and large molecules, mostly proteins, from passing. The filtered fluid then passes through the tubule, which sends needed minerals back to the bloodstream and removes wastes. The final product becomes urine.
What is kidney disease?
Because your kidneys filter waste, regulate blood pressure, make red blood cells
, and keep bones healthy
, when your kidneys aren’t working as well as they should, your overall health begins to decline. When your kidneys have been permanently damaged and aren’t functioning as well as they should, it’s called chronic kidney disease
(CKD), or kidney disease for short. The damage to the kidneys from a kidney disease can get worse over time. If the damage is very bad, your kidneys may stop working. This is called kidney failure
. If your kidneys fail, you will need dialysis or a kidney transplant
in order to live.
Chronic kidney disease can be caused by many different diseases. The most common causes are diabetes and high blood pressure. Some infections, inherited diseases and injuries can also cause a kidney disease.
Kidney disease often has no symptoms. Testing is the only way to know how well your kidneys are working. If you’re at risk, talk to your nephrologist
about getting tested, and encourage your at-risk loved ones to do the same. Testing is simple: a blood test and a urine test. If kidney disease is found, when it’s caught and treated early, it can often be stopped or slowed.