The opening of the iris. The pupil may appear to open (dilate) and close (constrict) but it is really the iris that is the prime mover; the pupil is merely the absence of iris. The pupil determines how much light is let into the eye. Both pupils are usually of equal size. If they are not, that is termed anisocoria (from "a-", not + "iso", equal + "kore", pupil = not equal pupils). Aside from the pupil and iris, the eye has a number of other components. These components include the cornea, lens, retina, macula, optic nerve and vitreous. The cornea is the clear front window of the eye that transmits and focuses light into the eye. The lens is the transparent structure inside the eye that focuses light rays onto the retina. The retina is the nerve layer that lines the back of the eye, senses light and creates impulses that travel through the optic nerve to the brain. The macula is a small area in the retina that contains special light-sensitive cells and allows us to see fine details clearly. The optic nerve is the nerve that connects the eye to the brain and carries the impulses formed by the retina to the visual cortex of the brain. The vitreous humor is a clear, jelly-like substance that fills the middle of the eye.
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The circular orifice in the center of the iris, through which the light rays enter the eye. SYN: pupilla [TA]. [L. pupilla]
- Adie p. SYN: Adie syndrome.
- amaurotic p. p. in an eye that is blind because of ocular or optic nerve disease; this p. will not contract to light except when the normal fellow eye is stimulated with light.
- Argyll Robertson p. a form of reflex iridoplegia characterized by miosis, irregular shape, and a loss of the direct and consensual pupillary reflex to light, with normal pupillary constriction to a near vision effort (light-near dissociation); often present in tabetic neurosyphilis. SYN: Robertson p..
- artificial p. an opening made by excision of a portion of the iris in order to improve the vision in cases of central opacity of the cornea or lens.
- Bumke p. dilation of the p. in response to anxiety or other psychic stimuli.
- cat's-eye p. a distorted, elongated p.; usually due to anterior segment anomaly.
- fixed p. a stationary p. unresponsive to all stimuli.
- Gunn p. SYN: Marcus Gunn p..
- Holmes-Adie p. SYN: Adie syndrome.
- Horner p. constricted p. due to impairment of sympathetic nerve innervation of the dilator muscle of the p.. SEE ALSO: Horner syndrome.
- Hutchinson p. dilation of the p. on the side of the lesion as part of a third nerve palsy; often due to herniation of the uncus of the temporal lobe through the tentorial notch.
- keyhole p. a p. with a coloboma.
- Marcus Gunn p. relative afferent pupillary defect. SYN: Gunn p..
- paradoxical p. paradoxical pupillary reflex.
- pinhole p. an extremely constricted p..
- seclusion of p. (se-kloo′zhun) the condition resulting from posterior annular synechia, in which the iris is bound down throughout the entire pupillary margin, but the p. is not occluded. SYN: exclusion of p..
- tadpole-shaped p. an intermittent, brief distortion and dilation of a p. that draws one part of the iris into a peak so that the p. resembles a tadpole; a temporary, benign condition associated with migraine that may leave the patient with Horner syndrome.
- tonic p. a general term for a p. with delayed, slow, long-lasting contractions to light and to a near vision effort, often with light-near dissociation; due to denervation and aberrant reinnervation of the iris sphincter; seen in various autonomic neuropathies and in Adie syndrome.

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pu·pil 'pyü-pəl n the contractile usu. round aperture in the iris of the eye

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the circular opening in the centre of the iris, through which light passes into the lens of the eye.
pupillary adj.

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pu·pil (puґpil) [L. pupilla girl] the opening at the center of the iris of the eye, through which light enters the eye; in official terminology, called pupilla. See also iris. pupillary adj

Medical dictionary. 2011.

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  • Pupil — Pu pil, n. [F. pupille, n. fem., L. pupilla the pupil of the eye, originally dim. of pupa a girl. See {Puppet}, and cf. {Pupil} a scholar.] (Anat.) The aperture in the iris; the sight, apple, or black of the eye. See the Note under {Eye}, and… …   The Collaborative International Dictionary of English

  • pupil — PUPÍL, Ă, pupili, e, s.m. şi f. Persoană minoră aflată sub tutela sau în grija cuiva (altul decât părinţii). – Din fr. pupille, lat. pupillus. Trimis de ana zecheru, 09.12.2007. Sursa: DEX 98  pupíl s. m., pl. pupíli Trimis de siveco, 09.12.2007 …   Dicționar Român

  • Pupil — Pu pil, n. [F. pupille, n. masc. & fem., L. pupillus, pupilla, dim. of pupus boy, pupa girl. See {Puppet}, and cf. {Pupil} of the eye.] 1. A youth or scholar of either sex under the care of an instructor or tutor. [1913 Webster] Too far in years… …   The Collaborative International Dictionary of English

  • pupil — Ⅰ. pupil [1] ► NOUN 1) a person who is taught by another, especially a schoolchild. 2) Brit. a trainee barrister. ORIGIN from Latin pupillus little boy and pupilla little girl . Ⅱ. pupil [2] …   English terms dictionary

  • pupil — pupil1 [pyo͞o′pəl] n. [ME pupille < MFr < L pupillus, pupilla, orphan, ward, dim. of pupus, boy, pupa, girl: see PUPA] 1. a person, esp. a young person, under the supervision of a teacher or tutor, as in school 2. Civil Law a minor under… …   English World dictionary

  • pupil — index disciple, neophyte, novice, protégé Burton s Legal Thesaurus. William C. Burton. 2006 …   Law dictionary

  • Pupil — Egalement Pupile, Pupille. Le nom, assez rare, se rencontre dans diverses régions, le plus souvent méridionales (Tarn et Garonne notamment). Issu du latin pupilius, il a en gros le même sens qu aujourd hui (enfant confié à un tuteur) …   Noms de famille

  • pupil — [n] person who is learning something adherent, attendant, beginner, bookworm*, brain*, catechumen, disciple, first year student, follower, graduate student, junior, learner, neophyte, novice, satellite, scholar, schoolboy/ girl, senior, sophomore …   New thesaurus

  • pupil — {{/stl 13}}{{stl 8}}rz. mos V, lm M. e, D. ów || i {{/stl 8}}{{stl 7}} człowiek (także zwierzę) przez kogoś faworyzowany, będący czyimś ulubieńcem; faworyt, beniaminek : {{/stl 7}}{{stl 10}}Chłopiec od najmłodszych lat był pupilem dziadka. Ten… …   Langenscheidt Polski wyjaśnień

  • Pupil — The pupil is the hole that is located in the center of the iris of the eye and that controls the amount of light that enters the eye.Cassin, B. and Solomon, S. Dictionary of Eye Terminology . Gainsville, Florida: Triad Publishing Company, 1990.]… …   Wikipedia

  • pupil — pupil1 pupilless, adj. /pyooh peuhl/, n. 1. a person, usually young, who is learning under the close supervision of a teacher at school, a private tutor, or the like; student. 2. Civil Law. an orphaned or emancipated minor under the care of a… …   Universalium

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