黄斑　

WordNet

a small yellowish central area of the retina that is rich in cones and that mediates clear detailed vision (同)macula_lutea, macular_area, yellow_spot
a patch of skin that is discolored but not usually elevated; caused by various diseases (同)macula

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(特に,花・葉が)不規則な色の斑点がある,まだら模様の

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/11/26 09:25:21」(JST)

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This article is about the macula of the human eye. For other uses of the term macula, see: Macula (disambiguation)

Fundus photographs of the right eye (left image) and left eye (right image), seen from front so that left in each image is to the person's right. The gaze is into the camera, so in each picture the macula is in the center of the image, and the optic disk is located towards the nose.

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 6 mm^[1] 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, high resolution vision. The macula also contains the parafovea and perifovea.

Because the macula is yellow in color it absorbs excess blue and ultraviolet light that enter the eye, and acts as a natural sunblock (analogous to sunglasses) for this area of the retina. The yellow colour comes from its content of lutein and zeaxanthin, which are yellow xanthophyll carotenoids, derived from the diet. Zeaxanthin predominates at the macula, while lutein predominates elsewhere in the retina. There is some evidence that these carotenoids protect the pigmented region from some types of macular degeneration.

Structures in the macula are 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[edit]

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 from 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.)

In the case of Occipitoparietal ischemia owing to occlusion of elements of either posterior cerebral artery, patients may display cortical blindness (which, rarely, can involve blindness that the patient denies having, as seen in Anton's Syndrome), yet display sparing of the macula. This selective sparing is due to the collateral circulation offered to macular tracts by the middle cerebral artery.^[2] Neurological examination that confirms macular sparing can go far in representing the type of damage mediated by an infarct, in this case, indicating that the caudal visual cortex (which is the principal recipient of macular projections of the optic nerve) has been spared. Further, it indicates that cortical damage rostral to, and including, lateral geniculate nucleus is an unlikely outcome of the infarction, as too much of the lateral geniculate nucleus is, proportionally, devoted to macular-stream processing.^[3]

References[edit]

^ Anita Hendrickson, 2005. Organization of the Adult Primate Fovea. In: P. Penfold, J. Provis, 2005. Macular Degeneration. Berlin: Springer. Ch.1.
^ Helseth,, Erek. "Posterior Cerebral Artery Stroke". Medscape Reference. Medscape. Retrieved 23 October 2011.
^ Siegel, Allan; Sapru, Hreday N. (2006). Betty Sun, ed. Essential Neuroscience (First Revised ed.). Baltimore, Maryland: Lippincott Williams & Wilkins. ISBN 978-0-7817-9121-2.

Additional images[edit]

The interior of the posterior half of the left eyeball.
A fundus photograph showing the macula as a spot to the left. The optic disc is the area on the right where blood vessels converge. The grey, more diffuse spot in the centre is a shadow artifact.

External links[edit]

MedlinePlus Encyclopedia 002252

UpToDate Contents

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1. 加齢黄斑変性：臨床像、病因、および診断 age related macular degeneration clinical presentation etiology and diagnosis
2. 救急外来における眼部損傷の概要 overview of eye injuries in the emergency department
3. 急性持続性視力喪失が認められた成人に対するアプローチ approach to the adult with acute persistent visual loss
4. 網膜色素変性症：臨床症状および診断 retinitis pigmentosa clinical presentation and diagnosis
5. 網膜剥離 retinal detachment

English Journal

A comparative study of chronic kidney disease in dogs and cats: Induction of cyclooxygenases.

Yabuki A, Mitani S, Sawa M, Mizukami K, Fujiki M, Yamato O.SourceLaboratory of Veterinary Clinical Pathology, Department of Veterinary Medicine, Kagoshima University, Korimoto 1-21-24, Kagoshima 890-0065, Japan.
Research in veterinary science.Res Vet Sci.2012 Oct;93(2):892-7. Epub 2012 Jan 13.
The present study investigated whether renal cyclooxygenase (COX) induction is associated with the severity of chronic kidney disease (CKD) in dogs and cats. The collected kidneys were examined histopathologically and immunohistochemically. The immunoreactivities of COX-1 and COX-2 were evaluated qu
PMID 22244709

Nephron segment identification in the normal canine kidney by using lectin histochemistry.

Yabuki A, Mitani S, Mizukami K, Yamato O.SourceLaboratory of Veterinary Clinical Pathology, Department of Veterinary Medicine, Kagoshima University, Japan.
Research in veterinary science.Res Vet Sci.2012 Oct;93(2):560-4. Epub 2012 Jan 2.
Lectin-binding patterns in normal canine kidneys were histochemically investigated using eight lectins. WGA, ConA, and RCA-I showed positive signals in glomerular capillary walls, with signals for RCA-I being detected heterogeneously. In tubular segments, signals for WGA, s-WGA, ConA, and RCA-I were
PMID 22217909

Japanese Journal

〈Review〉Kidney and Hypertension

Arima Shuji
Acta Medica Kinki University 37(1), 1-8, 2012-6
[Abstract]　The kidney plays an important role in the control of systemic blood pressure by regulating the composition of body fluid and electrolytes and by producing and releasing various vasoactive s …
NAID 120004226575

Macular choroidal thickness and volume in eyes with angioid streaks measured by swept source optical coherence tomography.

Ellabban Abdallah A,Tsujikawa Akitaka,Matsumoto Akiko,Ogino Ken,Hangai Masanori,Ooto Sotaro,Yamashiro Kenji,Akiba Masahiro,Yoshimura Nagahisa
American journal of ophthalmology 153(6), 1133-1143.e1, 2012-06
… [Purpose]: To study the mean choroidal thickness and volume of the macula in eyes with angioid streaks using swept source optical coherence tomography (OCT) in the 1050-nm wavelength range. … Mean choroidal thickness of the macula in Group 2 (218.9 ± 46.8 μm) was as great as that in Group 1 (218.8 ± 69.2 μm). …
NAID 120004161067

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リンク元	「黄斑」「variegated」「macular」「macule」「maculae」
拡張検索	「acoustic macula」「Callosobruchus maculatus」
関連記事	「macul」