Table of Contents
Urinary incontinence is the inability to control urination. It may be temporary or permanent, and can result from a variety of problems in the urinary tract. Urinary incontinence is generally divided into four types:
- Stress incontinence
- Urge incontinence
- Overflow incontinence
- Functional incontinence
Often, more than one type of incontinence is present. When this occurs, it is called mixed incontinence. Because incontinence is a symptom, rather than a disease, it is often hard to determine the cause. In addition, a variety of conditions may be the cause.
The urinary system helps to maintain proper water and salt balance throughout the body:
- The process of urination begins in the two kidneys, which process fluids and eliminate water and waste products to produce urine.
- Urine flows out of the kidneys into the bladder through two long tubes called ureters.
- The bladder is a sac that acts as a reservoir for urine. It is lined with a tissue membrane and enclosed in a powerful muscle called the detrusor. The bladder rests on top of the pelvic floor. This is a muscular structure similar to a sling running between the pubic bone in front to the base of the spine.
- The bladder stores the urine until it is eliminated from the body via a tube called the urethra, which is the lowest part of the urinary tract. (In men it is enclosed in the penis. In women it leads directly out.)
- The connection between the bladder and the urethra is called the bladder neck. Strong muscles called sphincter muscles encircle the bladder neck (the smooth internal sphincter muscles) and urethra (the fibrous external sphincter muscles).
|Click the icon to see an animation about urination.|
The Process of Urination
Review Date: 07/26/2010
Reviewed By: Harvey Simon, MD, Editor-in-Chief, Associate Professor of Medicine, Harvard Medical School; Physician, Massachusetts General Hospital. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.