About the Urinary System

The urinary system may not be the most glamorous part of the human body, but it's certainly necessary for healthy existence -- and if something goes wrong with it, the results can range from embarrassing (such as incontinence) to dangerous (diseases of the bladder or kidneys). The urinary system is relatively simple and is made up of only a few organs, which are relatively close together in the body. These organs help keep the body clean.

Purpose

• The urinary system helps filter waste products out of your body -- specifically a waste product called urea. Urea is formed when protein from food is broken down in the body. The urea runs through the bloodstream to the urinary system, where it is removed from the blood and mixed with water and some other waste products to form urine. The urine then is stored until it is time to urinate.

Kidneys

• The kidneys are the first stop in the urinary system. These fist-sized organs are located below the rib cage towards the back of the body. The kidneys contain little balls of blood vessels and tubes called nephrons. The nephrons strip out the urea and send a mix of urea and water -- the substance called urine -- down the tubes. The urine travels through a large tube called the ureter to reach the bladder.

Bladder

• The bladder serves as the body's urine storage system. It's a big hollow muscle located in your pelvis that, when full of urine, can swell up like a balloon. A healthy bladder can hold up to two cups of urine for five hours. Nerves inside your bladder serve as "warning signals," sending warning messages that the bladder is filling up.

Sphincter/Urethra

• The urethra is the tube that leads from the bladder to out of the body -- located in the vulva in women and in the penis in men. Muscles called urinary sphincters sit at the top of the urethra and close tightly to keep urine in. When it's time to urinate, the brain sends out signals to the sphincters to loosen and for the bladder to squeeze. Urine then comes out of the body through the urethra.

Conditions

• There are several conditions that can affect the urinary system. Some are serious, while some can be painful but not life-threatening. Urinary tract infections are a relatively common complaint that can usually be cleared up with antibiotics. Kidney stones that form in the kidneys are extremely painful but not dangerous, while kidney disease can be debilitating. Incontinence can be a symptom of several conditions or a problem in and of itself.