Why do women not have internal urethral sphincters? Watch

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MedStudentt
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The above ^
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macpatgh-Sheldon
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@MedStudentt

Hi,

I think the use of the adjectives "internal" and "external" to describe the urethral sphincters is only descriptive and does not play any great role in predicting physiology. My answer below is provided after reference to Gray's Anatomy, particularly in view of the fact that I hated obs & gynae as some of my other posts openly declare!

The whole functional usefulness of the urethral sphincter is to prevent incontinence, and you can imagine that this can only be achieved by a ring of muscle that compresses the urethra, and therefore, intrinsically has to be "external". It is labelled the external urethral sphincter in the male and the urethrovaginal sphincter in the female, the latter because of the input of "an elegantly orchestrated system of muscles and connective tissue" (direct excerpt from Gray's) in and around the sphincter.

The other difference between the male and female urethral sphincters is that the male sphincter is located more distally, partly due to the presence of the prostate gland; in addition, the female sphincter can be arbitrarily divided into two parts: the compressor urethrae, which I suppose has the primary role of ensuring continence, and the urethrovaginal sphincter, that surrounds the vaginal wall, which is implicated in the condition called vaginissmus. For obvious reasons, the latter is not necessary, and for that matter, not possible in the male.

I would limit my coverage of this subject to its physiological and clinical relevance. In relation to function, it might be worth knowing that the sphincter has a striated part and a smooth muscle part, so firstly, micturition is partly under the control of the will, and secondly, as we all know (and I can only speak for myself [I am male]!), one can consciously constrict one's sphincter [with the striated muscle part] when desperate to go to the loo, and there is a long queue ). For the latter, with age, dilatation of the sphincter occurs, and can lead to incontinence, and that this is more common in females (especially after childbirth); it may also be worth knowing that, during coughing, etc. which raises intra-abdominal pressure, other mechanisms aid the prevention of extrusion of urine, but these may not be as efficient as one would like, and slight leakage can occur in this situation.

Sorry, slightly convoluted answer - hope it helps!

M
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theresheglows
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In males the internal urethral sphincter is required to prevent backflow of seminal fluid into the bladder during ejaculation.
For fairly obvious reasons females don't need this.
But the female urethral sphincters are actually more elaborate as they consist of 3 parts rather than 2; the sphincter urethrae, the urethrovaginal and the compressor muscles.

(Original post by macpatelgh)
@MedStudentt
use of the adjectives "internal" and "external" to describe the urethral sphincters is only descriptive and does not play any great role in predicting physiology.
this
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Etomidate
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Because patriarchy.
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MedStudentt
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(Original post by macpatelgh)
@MedStudentt

Hi,

I think the use of the adjectives "internal" and "external" to describe the urethral sphincters is only descriptive and does not play any great role in predicting physiology. My answer below is provided after reference to Gray's Anatomy, particularly in view of the fact that I hated obs & gynae as some of my other posts openly declare!

The whole functional usefulness of the urethral sphincter is to prevent incontinence, and you can imagine that this can only be achieved by a ring of muscle that compresses the urethra, and therefore, intrinsically has to be "external". It is labelled the external urethral sphincter in the male and the urethrovaginal sphincter in the female, the latter because of the input of "an elegantly orchestrated system of muscles and connective tissue" (direct excerpt from Gray's) in and around the sphincter.

The other difference between the male and female urethral sphincters is that the male sphincter is located more distally, partly due to the presence of the prostate gland; in addition, the female sphincter can be arbitrarily divided into two parts: the compressor urethrae, which I suppose has the primary role of ensuring continence, and the urethrovaginal sphincter, that surrounds the vaginal wall, which is implicated in the condition called vaginissmus. For obvious reasons, the latter is not necessary, and for that matter, not possible in the male.

I would limit my coverage of this subject to its physiological and clinical relevance. In relation to function, it might be worth knowing that the sphincter has a striated part and a smooth muscle part, so firstly, micturition is partly under the control of the will, and secondly, as we all know (and I can only speak for myself [I am male]!), one can consciously constrict one's sphincter [with the striated muscle part] when desperate to go to the loo, and there is a long queue ). For the latter, with age, dilatation of the sphincter occurs, and can lead to incontinence, and that this is more common in females (especially after childbirth); it may also be worth knowing that, during coughing, etc. which raises intra-abdominal pressure, other mechanisms aid the prevention of extrusion of urine, but these may not be as efficient as one would like, and slight leakage can occur in this situation.

Sorry, slightly convoluted answer - hope it helps!

M
Perfect, just what I was after! Thank you so much x
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Hanna13
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Both sexes have internal
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ecolier
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(Original post by Hanna13)
Both sexes have internal
Thank you for registering just to post this. However I have closed this thread because (1) it's 15 months since last posted (2) it appears OP was satisfied with the answers provided. Please make a new thread if you have any specific questions.
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