retina
The definitions used in this glossary of terminology either have been provided by the authors of the articles, or have been extracted wholly or in part, or paraphrased from the following sources: The American Medical Association Encyclopedia of Medicine, Charles B. Clayman, MD, Medical Editor, Random House, New York, 1989; Biotechnology from A to Z, 2d Edition, William Bains, Oxford University Press, New York, New York, 2002; A Dictionary of Genetics, 6th Edition, Robert C. King and William D. Stansfield, Oxford University Press, New York, New York, 2002; Dorland's Illustrated Medical Dictionary, 29th and 30th Editions, W. B. Saunders Company, Philadelphia, 2000, 2003; Genes VII, Benjamin Lewin, Oxford University Press, New York, New York, 2000; The Gale Encyclopedia of Genetic Disorders, Volumes I and II, Stacey L. Blachford, Ed., Thomson Learning, New York, New York, 2002; The Merriam-Webster Dictionary, Merriam-Webster, Inc., Springfield, Massachusetts, 1997; Molecular Biology of the Cell, 3rd Edition, Bruce Alberts, et al., Garland Publishing, 1994; The Random House Dictionary of the English Language, Unabridged Edition, 1966; Webster's Ninth New Collegiate Dictionary, 1991.
DEFINITION:
- retina
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The light-sensitive membrane that lines the inside of the back of the eye (like film in a camera) on which images are cast by the cornea and lens. The retina contains specialized nerve cells (the rods and cones) that convert light energy into nerve impulses. The retina also contains a network of connecting and integrating cells, some with very long fibers, that convey these impulses back along the optic nerve to the brain.
The rods are exceptionally sensitive, responding to very dim light. The cones are less sensitive but are responsible for color vision; different cones produce impulses that vary in strength with the color of the light striking them.
Near the center of the retina is the fovea. Here, retinal blood vessels are absent; the light-sensitive cells (almost all cones) are packed so that vision has the highest resolution.
Used in 4 Article translations
Used in 4 Article translations