pupillary sphincter

noun
a ring of smooth muscle surrounding the iris
Part Holonyms: ↑eye, ↑oculus, ↑optic

Useful english dictionary. 2012.

Look at other dictionaries:

  • Sphincter — A sphincter is an anatomical structure, or a circular muscle, that normally maintains constriction of a natural body passage or orifice and which relaxes as required by normal physiological functioning. Sphincters are found in many animals; there …   Wikipedia

  • 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

  • Pupillary response — or dilation of the pupil is a physiological response that varies the size of the pupil of the eye via the iris dilator muscle. It can have a variety of causes. It may be an involuntary reflex reaction to exposure to light. Or it may indicate… …   Wikipedia

  • Pupillary reflex — refers to one of the reflexes associated with pupillary function. Types include: Pupillary light reflex Accommodation reflex Although pupillary dilation is not usually called a reflex , it is still usually considered a part of this topic.… …   Wikipedia

  • sphincter — A muscle that encircles a duct, tube, or orifice in such a way that its contraction constricts the lumen or orifice. SYN: musculus s. [TA], s. muscle [TA]. [G. sphinkter, a band or lace] s. of ampulla s. of hepatopancreatic ampulla. anatomic s.… …   Medical dictionary

  • pupillary reflex — noun reflex contraction of the sphincter muscle of the iris in response to a bright light (or certain drugs) causing the pupil to become smaller • Syn: ↑light reflex, ↑miosis, ↑myosis • Derivationally related forms: ↑myotic (for: ↑myosis), ↑ …   Useful english dictionary

  • pupillary — Relating to the pupil. p. light near dissociation a stronger near pupil response than light response; due to weak pupillomotor input, Argyll Robertson pupil, dorsal midbrain syndrome, or to misdirection of …   Medical dictionary

  • Iris sphincter muscle — Iris, front view. (Muscle visible but not labeled.) …   Wikipedia

  • anatomical sphincter — noun a ring of muscle that contracts to close an opening • Syn: ↑sphincter, ↑sphincter muscle • Hypernyms: ↑muscle, ↑musculus • Hyponyms: ↑physiological sphincter, ↑ …   Useful english dictionary

  • musculus sphincter pupillae — noun a ring of smooth muscle surrounding the iris • Syn: ↑pupillary sphincter • Hypernyms: ↑sphincter, ↑anatomical sphincter, ↑sphincter muscle • Part Holonyms: ↑eye, ↑oculus …   Useful english dictionary

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