Urinary
Incontinence
What does the bladder
control system look like?
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Parts of the bladder control system
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Most of your bladder
control system lies inside your pelvis. Stand with your hands on your
hips. The bones under your hands are the pelvic bones. Your pelvis is shaped
like a big bowl.
The bottom of this
"bowl" is the area between your legs. The striated and voluntary
muscles across this area are the pelvic floor muscles. Your bladder is a smooth muscle not under volitional
control. It is a balloon-shaped organ inside your pelvis, just below your belly
button. Your pelvic floor muscles
should be strong and tight to hold up your bladder in its proper place.
Your bladder should stay
relaxed when it is full of urine. But when you go to the bathroom, the bladder
muscle should tighten. This squeezes urine out of the bladder.
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Parts of the bladder control system
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The sphincter (SFINK-tur)
muscles are two muscles that surround the tube that carries urine from your
bladder down to an opening in front of the vagina. The tube is called the urethra
(yoo-REE-thrah). Urine leaves your body through this tube.
The sphincters keep the
urethra closed by squeezing like tight rubber bands. The pelvic floor muscles
also keep the urethra closed. Urine
stays inside your body when the pelvic floor and sphincter muscles are tight and
the bladder is relaxed.
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Parts of the bladder control system
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Parts of the bladder control system: nerves and brain
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When the bladder is full,
nerves in your bladder signal the brain. That's when you get the
urge to go to the bathroom. Once you reach the toilet, your brain sends a
message down to the sphincter and pelvic floor muscles. It tells them to relax.
The brain signal also tells the bladder muscles to tighten up. That
squeezes urine out of the bladder.
Bladder control means you
urinate only when you want to. For good bladder control, all parts of your
system must work together.
- Pelvic muscles must
hold up the bladder and urethra.
- Sphincter muscles
must open and shut the urethra.
- Nerves must control
the muscles of the bladder and pelvic floor.
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Pregnancy and childbirth sometimes cause stress
incontinence.
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What causes bladder
control problems?
Most bladder control
problems happen when muscles are weak or too active. Problems may also happen
when nerve signals don't work properly.
If the sphincter muscles
that keep your urethra closed are weak, you may have accidents when you sneeze,
laugh, or lift a heavy object. This is called stress incontinence. It is
the most common type of bladder control problem.
Stress incontinence often occurs after childbirth. The pelvic floor
muscles stretch, weaken, or tear after vaginal childbirth.
The same muscles become weak after a woman stops having periods
(menopause). They weaken because they are no longer used (disuse atrophy) or
exercised.
Sometimes, the bladder
muscles become too active which causes a different problem. You may feel
strong, sudden urges to go to the bathroom, even if your bladder has little
urine in it. This kind of bladder problem is called urge incontinence or overactive
bladder. Some women with urge
incontinence perceive that they are not emptying their bladder effectively
because they are going to the bathroom frequently and emptying small amounts.
In truth, incontinence from an inability to empty the bladder (overflow
incontinence) is rare. You are
really experiencing a bladder storage problem.
Several things can cause your bladder to be too active such as a bladder
infection, nerve damage (sometimes from childbirth), drinking alcohol, and some
medicines.
For the urinary system to
do its job, muscles and nerves must work together to hold urine in the bladder
and then release it at the right time. Nerves carry messages from the bladder to
the brain to let it know when the bladder is full. They also carry messages from
the brain to the bladder, telling muscles either to tighten or release. A nerve
problem might affect your bladder control if the nerves that are supposed to
carry messages between the brain and the bladder do not work properly.
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Nerves
carry signals from the brain to the bladder and sphincter.
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What bladder
control problems does nerve damage cause?
Nerves that
work poorly can lead to three different kinds of bladder control problems.
Overactive
bladder. Damaged
nerves may send signals to the bladder at the wrong time, causing its muscles to
squeeze without warning. The symptoms of overactive bladder include
- urinary frequency--defined
as urination eight or more times a day or two or more times at night
- urinary urgency--the
sudden, strong need to urinate immediately
- urge incontinence--leakage
of urine that follows a sudden, strong urge
Poor
control of sphincter muscles.
Sphincter muscles surround the urethra and keep it closed to hold urine in the
bladder. If the nerves to the sphincter muscles are damaged, the muscles may
become loose and allow leakage or stay tight when you are
trying to release urine.
Urinary retention.
For some people, nerve damage means that their bladder muscles do not get the
message that it is time to release urine. If the bladder becomes too full, urine
may back up and the increasing pressure may damage the kidneys. Or urine that
stays too long may lead to an infection in the kidneys or bladder. Urinary
retention may also lead to overflow incontinence.
The
National Kidney and Urologic Diseases Information Clearinghouse (NKUDIC) is a
service of the National Institute of Diabetes and Digestive and Kidney Diseases
(NIDDK). The NIDDK is part of the National Institutes of Health under the U.S.
Department of Health and Human Services. This
e-text is not copyrighted. The clearinghouse encourages users of this e-pub to
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