sphincter muscle

▪ anatomy

any of the ringlike muscles surrounding and able to contract or close a bodily passage or opening. One of the most important human sphincter muscles is the sphincter pylori, a thickening of the middle layer of stomach muscle around the pylorus (opening into the small intestine) that holds food in the stomach until it is thoroughly mixed with gastric juices. Other sphincters are involved in excretion of waste: the sphincter ani externus keeps the anal opening closed by its normal contraction, and the sphincter urethrae is the most important voluntary control of urination. There is also a sphincter in the eye, the sphincter pupillae, a ring of fibres in the iris that contracts the pupil in the presence of bright light. Compare dilator muscle.

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sphincter muscle of male urethra external — sphincter muscle of membranous urethra musculus sphincter urethrae externus urethrae masculinae … Medical dictionary
sphincter muscle of urethra internal — sphincter muscle of urinary bladder musculus sphincter urethrae internus … Medical dictionary
sphincter muscle — noun a ring of muscle that contracts to close an opening • Syn: ↑sphincter, ↑anatomical sphincter • Hypernyms: ↑muscle, ↑musculus • Hyponyms: ↑physiological sphincter, ↑ … Useful english dictionary
sphincter muscle — musculus sphincter … Medical dictionary
sphincter muscle of urethra — sphincter urethrae muscle see musculus sphincter urethrae externus urethrae femininae and musculus sphincter urethrae externus urethrae masculinae … Medical dictionary
External sphincter muscle of male urethra — Muscle infobox Name = Sphincter urethrae membranaceae muscle Latin = musculus sphincter urethrae externus urethrae masculinae, musculus sphincter urethrae membranaceae GraySubject = 120 GrayPage = 429 Caption = The male urethra laid open on its… … Wikipedia
sphincter muscle of anus external — musculus sphincter ani externus … Medical dictionary
sphincter muscle of anus internal — musculus sphincter ani internus … Medical dictionary
sphincter muscle of bile duct — musculus sphincter ductus choledochi … Medical dictionary
sphincter muscle of female urethra external — musculus sphincter urethrae externus urethrae femininae … Medical dictionary

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sphincter muscle

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