What Is a Urinary Sphincter?

The muscles that contract around the urethra form the urinary sphincter.
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  • Written By: Katriena Knights
  • Edited By: A. Joseph
  • Last Modified Date: 04 September 2014
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The urinary sphincter, also referred to as the urethral sphincter, is a series of muscles that contract around the urethra in order to achieve bladder control. An internal urinary sphincter prevents flow of urine through the urinary tract from the bladder, and the external urinary sphincter provides additional voluntary control. Weakness or malfunction of these muscles can lead to urinary incontinence.

Function and structure of the urinary sphincter differs in men and women because of a different anatomical structure and different requirements of the muscle. For example, the internal urinary sphincter in men helps prevent urine from mixing with seminal fluid during ejaculation. In women, the external urinary sphincter consists of three separate muscles, one of which also contracts the vagina. Muscles to manage urinary flow can be controlled in both men and women by contracting the pelvic floor muscles.

Urinary incontinence is one of the most common problems associated with the urinary tract muscles. This complaint is particularly common with women who have borne children. The pelvic floor muscles can become weakened or damaged in the course of pregnancy and childbirth, making it difficult for women to contract these muscles in order to control the flow of urine through the urethra. Doctors often suggest physical therapy to strengthen the pelvic floor muscles to both men and women suffering from urinary incontinence. These exercises, also called Kegel exercises, are simple to perform and can greatly increase bladder control if practiced diligently.

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Men can suffer from urinary incontinence, as well, particularly after prostate surgery. In some cases, prostate surgery results in permanent intrinsic sphincter deficiency, in which the urinary sphincter no longer functions properly. Various treatments have been developed for this condition, including physical therapy or electrical stimulation therapy to strengthen the muscles, behavioral therapy, diet therapy and other approaches. Medications are sometimes prescribed, and severe cases might require surgery.

Other approaches to managing a weakened or atrophied urinary sphincter include placement of devices within the body that can reduce bladder leakage. Women can use pessaries, which are placed in the vagina and press against the urethra to hold it closed. Men sometimes are fitted with an artificial urinary sphincter, which is implanted within the body and controlled through a pressure pump located in the scrotum. Additional surgical approaches include creating an internal sling to help hold the urethra closed or a bladder neck suspension procedure that adds additional support to the neck of the bladder.

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seag47
Post 5

My son had a lot of problems with wetting the bed a few years ago. His doctor said that his body just hadn't developed full control over the urinary sphincter yet, and he recommended using a moisture alarm.

I put this alarm in the bedsheets, and when my son wet the bed, it would go off. Usually, he would sleep through it, but I would hear it and get up. I would make him get up and go to the bathroom while I put fresh sheets on the bed.

After awhile, his mind and body started responding subconsciously to the alarm. Though he would remain asleep when it went off, he would suddenly stop urinating, so there would only be a small puddle of urine in the bed. This alarm eventually trained him to wake up when he had to go.

Because of this experience, I think that urinary sphincter control is partly mental. He had to learn to exercise control, even though he wasn't fully aware of the mechanics of his body.

kylee07drg
Post 4

My grandmother's urinary sphincter has weakened with age, and she is now incontinent. She is too scared to use a pessary, though.

She has been wearing adult diapers for the past year, and surprisingly, she is fine with it. If I were her, I would want to pursue any other option that would keep me from having to have the urine held against my body, but she is old-fashioned, and she prefers simple methods.

I think it's sad that old age can do this to a person. I'm afraid that incontinence may be in my genes, but I know I will handle it differently.

Perdido
Post 3

@cloudel - I have heard of a couple of things that affect the urinary sphincter of a dog. Both can make them lose control of their bladder, and both require medication.

I have one young dog that has problems with incontinence, and the vet told me that it is because she was spayed so early in life. She said that she has a lack of certain hormones that help with urinary sphincter control, and she will unfortunately have to be on medication for the rest of her life to help her control her leaky bladder.

My other dog is eight years old, and she is losing control of her sphincter because of the aging process. She, too, will have to take medicine for as long as she lives.

Both dogs urinate on themselves in their sleep if they do not take their medicine. The tablets are chewable and flavored, so getting them to take them is no problem at all.

cloudel
Post 2

Has anyone here ever heard of a dog losing control of its bladder? Last week, I was dogsitting for a neighbor, and I noticed that the dog wet himself during the night. There was a big puddle on the bed, too, so it wasn't just a little trickle.

This probably has to do with the urinary sphincter somehow, but I don't know what the cause could be. I know he wasn't frightened by anything, so it must be physical rather than mental. I just wonder what could make a seemingly healthy, middle-aged dog leak like that.

ElizaBennett
Post 1

Kegels are great and they can be important for a lot of people, but a lot of women don't know that *squats* are also a great way to tone the pelvic floor and help out those urinary sphincters, especially before and after childbirth. Yep, those glutes are key to maintaining a healthy pelvic floor. Also from preventing that flat butt that a lot of old ladies get.

Traditional crunches can also strain your pelvic floor. Man or woman, if you've had trouble with incontinence, you might want to skip the crunches and take up alternative exercises like planks to protect your pelvic floor.

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