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macula

Did you mean: macula, Macula (archaeology), Macula (planetary geology)

 
Dictionary: mac·u·la   (măk'yə-lə) pronunciation
n., pl., -lae (-lē'), or -las.
  1. also mac·ule (-yūl') A discolored spot or area on the skin that is not elevated above the surface and is characteristic of certain conditions, such as smallpox, purpura, or roseola.
    1. An opaque spot on the cornea.
    2. The macula lutea.

[Middle English, from Latin.]

macular mac'u·lar adj.

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Pl. maculae [L.]
1. a stain, spot, or thickening;
2. an area distinguishable by color or otherwise from its surroundings. Often used alone to refer to the macula retinae.
3. a macule: a discolored spot on the skin that is not raised above the surface.
4. a corneal scar that can be seen without special optical aids; presenting as a gray spot intermediate between a nebula and a leukoma.
5. macula lutea.

  • m. acusticae — terminations of the vestibulocochlear nerve in the utricle and saccule.
  • m. adherens — see desmosome.
  • m. atrophica — a white atrophic patch on the skin.
  • m. corneae — a circumscribed opacity of the cornea.
  • m. cribrosa — a perforated spot or area; one of three perforated areas (inferior, medial and superior) in the wall of the vestibule of the ear through which branches of the vestibulocochlear nerve pass to the saccule, utricle and semicircular canals.
  • m. densa — a zone of heavily nucleated cells in the distal renal tubule.
  • m. folliculi — the point on the surface of a vesicular ovarian follicle where rupture occurs; follicular stigma.
  • m. germinativa — germinal area; the part of the conceptus where the embryo is formed.
  • inner ear m. — sensory receptor areas in the walls of the utriculus and sacculus which monitor the position of the head relative to gravity; see also macula sacculi, macula utriculi (below).
  • m. lutea — an irregular yellowish depression on the retina, lateral to and slightly below the optic disk. Called also macula retinae.
  • m. retinae — see macula lutea (above).
  • m. sacculi — a thickening on the wall of the saccule where the epithelium contains hair cells that receive and transmit vestibular impulses.
  • m. utriculi — a thickening in the wall of the utricle where the epithelium contains hair cells that are stimulated by linear acceleration and deceleration and by gravity.
Wikipedia: Macula of retina
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Macula of retina
Human eye cross-sectional view grayscale.png
Human eye cross-sectional view.
Latin macula lutea
Gray's subject #225 1015
MeSH Macula+Lutea

The macula or macula lutea (from Latin macula, "spot" + lutea, "yellow") is an oval-shaped highly pigmented yellow spot near the center of the retina of the human eye. It has a diameter of around 5 mm and is often histologically defined as having two or more layers of ganglion cells. Near its center is the fovea, a small pit that contains the largest concentration of cone cells in the eye and is responsible for central vision, and also contains the parafovea and perifovea.

Because the macula is yellow in colour it absorbs excess light that enters the eye and acts as natural sunglasses.

It is specialized for high acuity vision. Within the macula are the fovea and foveola which contain a high density of cones (photoreceptors with high acuity).

Clinical significance

Whereas loss of peripheral vision may go unnoticed for some time, damage to the macula will result in loss of central vision, which is usually immediately obvious. The progressive destruction of the macula is a disease known as macular degeneration and can sometimes lead to the creation of a macular hole. Macular holes are rarely caused by trauma, but if a severe blow is delivered it can burst the blood vessels going to the macula, destroying it.

Visual input to the macula occupies a substantial portion of the brain's visual capacity. As a result, some forms of visual field loss can occur without involving the macula; this is termed macular sparing. (For example, visual field testing might demonstrate homonymous hemianopia with macular sparing.)

See also

Additional images


Translations: Macula
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Dansk (Danish)
n. - plet på huden, solplet

Nederlands (Dutch)
vlek, huidvlek, gele vlek (in oog), zonnevlek

Français (French)
n. - (Méd) macula

Deutsch (German)
n. - Fleck, gelber Fleck

Ελληνική (Greek)
n. - κηλίδα

Italiano (Italian)
macula, macchia (spec. del sole)

Português (Portuguese)
n. - mácula (f)

Русский (Russian)
пятно (на солнце)

Español (Spanish)
n. - mácula, mancha

Svenska (Swedish)
n. - macula, (hud)fläck, solfläck

中文(简体)(Chinese (Simplified))
斑点, 黑点, 污点

中文(繁體)(Chinese (Traditional))
n. - 斑點, 黑點, 污點

한국어 (Korean)
n. - 반점, 기미, 멍, 흑점

日本語 (Japanese)
n. - あざ, 黒点

العربيه (Arabic)
‏(الاسم) بقعه داكنه‏

עברית (Hebrew)
n. - ‮בהרת, איזור ברשתית העין, כתם-שמש‬


 
 

Did you mean: macula, Macula (archaeology), Macula (planetary geology)


 

Copyrights:

Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
Wikipedia. This article is licensed under the Creative Commons Attribution/Share-Alike License. It uses material from the Wikipedia article "Macula of retina" Read more
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