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Glite Dictionary
pupillary sphincter

pupillary sphincter

8.9
A ring of muscle in the coloured part of the eye that makes the pupil smaller
  • noun
  • /ˈpjuːpɪˌlɛri ˈsfɪŋktər/
  • Specialized
translation icon : esfínter pupilar
  • The pupillary sphincter controls how much light enters the eye by adjusting the size of the pupil.

Examples

  • During bright light conditions, the pupillary sphincter contracts.

  • Damage to the pupillary sphincter may result in abnormal pupil reactions to light.

  • Doctors examined the patient's pupillary sphincter function during the eye exam.

  • The pupillary sphincter controls the amount of light entering the eye.

  • The pupillary sphincter contracts to reduce the size of the pupil in bright light.

  • During the eye examination, the doctor tested the function of the pupillary sphincter.

  • An injury to the pupillary sphincter can affect how the pupil reacts to changes in light.

Synonyms

musculus sphincter pupillae
vspupillary sphincter
  • Specialized
8.9

A ring of muscle in the eye that makes the pupil smaller in bright light

is the same structure but described as within the iris rather than around it

Surface Forms

pupillary sphincter singular
pupillary sphincters plural

Morphology

pupillary + sphincter

The meaning is directly compositional: 'pupillary' (pertaining to the pupil) + 'sphincter' (a muscle that closes an opening) yields a muscle that constricts the pupil. This formation is a straightforward medical compound and is cross-linguistically parallel (e.g., Spanish/French medical terms), so a learner who knows both constituents will readily infer the MWE meaning.

Etymology

Pupillary sphincter names the small ring of muscle in the colored part of the eye that squeezes the pupil to make it smaller. When the sphincter tightens, the pupil gets smaller and less light comes in, so it 'controls' how much light enters the eye.