Detrusor

Detrusor urinae muscle
Urinary bladder
Details
Origin	posterior surface of the body of the pubis
Insertion	prostate (male), vagina (female)
Nerve	Sympathetic - hypogastric n. (T10-L2) Parasympathetic - pelvic splanchnic nerves (S2-4)
Actions	Sympathetic relaxes, to store urine Parasympathetic contracts, to urinate
Identifiers
Latin	musculus detrusor vesicae urinariae
TA	A08.3.01.014
FMA	68018
Anatomical terms of muscle []

Sympathetic - hypogastric n. (T10-L2)

Sympathetic relaxes, to store urine

The detrusor urinae muscle, also detrusor 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.

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 and its capsule. These fibers pass, in a more or less 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 and intersect one another.

The 3 layers of muscles are arranged longitudinal-circular-longitudinal from innermost to outermost.

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Wikipedia