Detrusor muscle
{{Short description|Muscle of the bladder that expels urine}}
{{Infobox muscle
| Name = Detrusor muscle
| Latin = musculus detrusor vesicae urinariae
| Image = Illu bladder.jpg
| Caption = Urinary bladder
| Width = 260
| Origin = Posterior surface of the body of the pubis
| Insertion = Prostate (male), vagina (female)
| Blood =
| Nerve = Sympathetic - hypogastric n. (T10-L2)
Parasympathetic - pelvic splanchnic nerves (S2-4)
| Action = Sympathetic relaxes, to store urine
Parasympathetic contracts, to urinate
| Antagonist =
|Artery=Internal pudendal artery, inferior vesical artery}}
The detrusor muscle, also detrusor urinae muscle, muscularis propria of the urinary bladder and (less precise) muscularis propria, is smooth muscle found in the wall of the bladder. The detrusor muscle remains relaxed to allow the bladder to store urine, and contracts during urination to release urine. Related are the urethral sphincter muscles which envelop the urethra to control the flow of urine when they contract.
Structure
The fibers of the detrusor muscle arise from the posterior surface of the body of the pubis in both sexes (musculi pubovesicales), and in the male from the adjacent part of the prostate. These fibers pass, in a more or less longitudinal manner, up the inferior surface of the bladder, over its apex, and then descend along its fundus to become attached to the prostate in the male, and to the front of the vagina in the female. At the sides of the bladder the fibers are arranged obliquely and intersect one another.
The three layers of muscles are arranged longitudinal-circular-longitudinal from innermost to outermost.
Nerve supply
The detrusor muscle is innervated by the autonomic nervous system.
During urination, parasympathetic pelvic splanchnic nerves act primarily on postganglionic M3 receptors to cause contraction of the detrusor muscle.{{Cite web |title=Bladder: Pharmacology of the detrusor receptors |url=https://www.urology-textbook.com/bladder-detrusor-receptors.html |access-date=2024-06-07 |website=www.urology-textbook.com}}{{Cite journal |last=Sellers |first=Donna J. |last2=Chess-Williams |first2=Russ |date=2012 |title=Muscarinic agonists and antagonists: effects on the urinary bladder |url=https://pubmed.ncbi.nlm.nih.gov/22222707/ |journal=Handbook of Experimental Pharmacology |issue=208 |pages=375–400 |doi=10.1007/978-3-642-23274-9_16 |issn=0171-2004 |pmid=22222707}}{{Cite journal |last=Giglio |first=Daniel |last2=Tobin |first2=Gunnar |date=2009 |title=Muscarinic receptor subtypes in the lower urinary tract |url=https://pubmed.ncbi.nlm.nih.gov/19295256/ |journal=Pharmacology |volume=83 |issue=5 |pages=259–269 |doi=10.1159/000209255 |issn=1423-0313 |pmid=19295256}}
At other times, the muscle is kept relaxed via sympathetic branches from the inferior hypogastric plexus to allow the bladder to fill.{{Citation |last1=Ho |first1=MAT H. |title=CHAPTER 51 - Lower Urinary Tract Disorders in Postmenopausal Women |date=2007-01-01 |work=Treatment of the Postmenopausal Woman (Third Edition) |pages=693–737 |editor-last=Lobo |editor-first=Rogerio A. |url=https://www.sciencedirect.com/science/article/pii/B9780123694430500636 |access-date=2021-02-05 |place=St. Louis |publisher=Academic Press |language=en |isbn=978-0-12-369443-0 |last2=Bhatia |first2=NARENDER N.}}
Clinical significance
In older adults over 60 years in age, the detrusor muscle may cause issues in voiding the bladder, resulting in uncomfortable urinary retention.{{cite journal|last1=Stoffel|first1=JT|date=September 2017|title=Non-neurogenic Chronic Urinary Retention: What Are We Treating?|journal=Current Urology Reports|volume=18|issue=9|pages=74|doi=10.1007/s11934-017-0719-2|pmid=28730405|s2cid=12989132 }}
The bladder also contains β3 adrenergic receptors, and pharmacological agonists of this receptor are used to treat overactive bladder.
The mucosa of the urinary bladder may herniate through the detrusor muscle.{{Citation|title=Bladder Diverticula|date=2018-01-01|url=https://www.sciencedirect.com/science/article/pii/B9780323477789501537|work=Imaging in Pediatrics|pages=205|editor-last=Merrow|editor-first=A. Carlson|publisher=Elsevier|language=en|doi=10.1016/b978-0-323-47778-9.50153-7|isbn=978-0-323-47778-9|access-date=2021-02-05|editor2-last=Hariharan|editor2-first=Selena|url-access=subscription}} This is most often an acquired condition due to high pressure in the urinary bladder, damage, or existing connective tissue disorders.
See also
References
External links
- {{KansasHistology|urinary/renal18}}{{dead link|date=January 2024}}
- {{Cite journal |last=Swami |first=K.S. |last2=Feneley |first2=R.C.L. |last3=Hammonds |first3=J.C. |last4=Abrams |first4=P. |title=Detrusor myectomy for detrusor overactivity: a minimum 1-year follow-up |url=http://www.urologyjournal.us/studies/detrusor-myectomy-overactivity-year-follow-up.html |url-status=dead |archive-url=https://web.archive.org/web/20120714075550/http://www.urologyjournal.us/studies/detrusor-myectomy-overactivity-year-follow-up.html |archive-date=Jul 14, 2012 |journal =The Medical Journal of Urology}}
{{Urinary system}}
{{Authority control}}