Urinary Incontinence is the involuntary loss of urine from the bladder.
Urination is a complex activity. The bladder is a balloon-like organ that lies in the lowest part of the abdomen. The bladder stores urine that is produced by the kidneys and is transported to it by the ureters. Urine is released through the urethra which carries urine to the outside of the body. Urination requires integrated activity involving nerves, muscles, the spinal cord, and the brain.
The bladder has two types of muscles: one is a muscular sac that stores urine and squeezes to empty. The other is a circular group of muscles at the bottom or neck of the bladder that automatically stay contracted to hold the urine in and automatically relax when the sac contracts to let the urine into the urethra. In males, an enlarged prostate may interfere with the passage of urine. Another group of muscles below the bladder (pelvic floor muscles) can be trained to contract to hold urine within the body.
In a continent individual, as the bladder fills the brain receives messages from the expanding bladder and begins to send messages to the bladder to keep it from automatically emptying. When continent, a person is able to control the time and the place to void.
National Association for Continence: www.nafc.org
Simon Foundation for Continence: www.simonfoundation.org
National Kidney and Urologic Diseases Information Clearinghouse: www.niddk.nih.gov