Retina: [TA] Grossly, the retina consists of three parts: optic, ciliary, and iridial. The optic part, the physiologic portion that receives the visual light rays, is further divided into two parts, the pigmented part (pigment epithelium) and the nervous part, which are arranged in the following ten layers: pigmented layer; layer of inner and outer segments (of rods and cones); outer limiting layer (actually a row of junctional complexes); outer nuclear layer; outer plexiform layer; inner nuclear layer; inner plexiform layer; ganglionic (cell) layer; layer of nerve fibers; and inner limiting layer. Layers 2-10 comprise the neural layer. At the posterior pole of the visual axis is the macula, in the center of which is the fovea, the area of acute vision. Here, layers 6-9 and blood vessels are absent, and only elongated cones are present. About 3 mm medial to the fovea is the optic disc, where axons of the ganglionic cells converge to form the optic nerve. The ciliary and iridial parts of the retina are forward prolongations of the pigmented layer and a layer of supporting columnar or epithelial cells over the ciliary body and the posterior surface of the iris, respectively. SYN: optomeninx. [Mediev. L. prob. fr. L. rete, a net]
Source: Stedman's Medical Spellchecker, © 2006 Lippincott Williams & Wilkins. All rights reserved.
Retina: The light-sensitive layers of nerve tissue at the back of the eye that receive images and sends them as electric signals through the optic nerve to the brain.
Source: National Institute of Health
Retina: the light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve.
Source: WordNet 2.1
Retina: innermost of the three tunics of the eyeball, the retina is a ten layered nervous tissue membrane; it is continuous with the optic nerve and receives images of external objects and transmits visual impulses to the brain; its outer surface is in contact with the choroid and the inner surface with the vitreous body; the outermost layer is pigmented, whereas the inner nine layers are transparent.
Source: CRISP
Retina: The ten-layered nervous tissue membrane of the eye. It is continuous with the OPTIC NERVE and receives images of external objects and transmits visual impulses to the brain. Its outer surface is in contact with the CHOROID and the inner surface with the VITREOUS BODY. The outer-most layer is pigmented, whereas the inner nine layers are transparent.
Source: MeSH 2007
Retina (organ): Light receiver inside and at the back of the eye.
Retina (organ): The retina is the receiver of visual images at the back of the eye. Light passes through the frontal lens, then through the clear gel-like vitreous in the inner eyeball, to the retina at the back of the eye, which then sends electrical signals down the optic nerve to the brain.
Retina (organ): The retina is a paper-thin tissue that lines the back of the eye and sends visual signals to the brain. In the middle of the retina is a tiny area called the macula. The macula is made up of millions of light-sensing cells that help to produce central vision. (Source: excerpt from Are You at Risk for Age-Related Macular Degeneration: NEI)
The retina is a light-sensitive tissue at the back of the eye. When light enters the eye, the retina changes the light into nerve signals. The retina then sends these signals along the optic nerve to the brain. Without a retina, the eye cannot communicate with the brain, making vision impossible. (Source: excerpt from Facts About Diabetic Retinopathy: NEI)
Retina (organ): See Retina (organ information).
More information on organs: Retina:
Source - MeSH 2007
Source - MeSH 2007
Source - CRISP
Source - MeSH 2007
Source - CRISP
Source - WordNet 2.1
Source: CRISP
The following list attempts to classify Retina into categories where each line is subset of the next.
Source: WordNet 2.1
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