Definitions for retina
ˈrɛt n ə, ˈrɛt nə; ˈrɛt nˌireti·na

Princeton's WordNetRate this definition:5.0 / 1 vote

1. retinanoun

   the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve

WiktionaryRate this definition:1.0 / 1 vote

1. retinanoun

   The thin layer of cells at the back of the eyeball where light is converted into neural signals sent to the brain.

2. Etymology: From retina, the diminutive form of rete, probably from the phrase (tunica), literally "net-like tunic", used to describe the blood vessel system at the back of the eye.

WikipediaRate this definition:0.0 / 0 votes

1. Retina

   The retina (from Latin: rete "net") is the innermost, light-sensitive layer of tissue of the eye of most vertebrates and some molluscs. The optics of the eye create a focused two-dimensional image of the visual world on the retina, which then processes that image within the retina and sends nerve impulses along the optic nerve to the visual cortex to create visual perception. The retina serves a function which is in many ways analogous to that of the film or image sensor in a camera. The neural retina consists of several layers of neurons interconnected by synapses and is supported by an outer layer of pigmented epithelial cells. The primary light-sensing cells in the retina are the photoreceptor cells, which are of two types: rods and cones. Rods function mainly in dim light and provide monochromatic vision. Cones function in well-lit conditions and are responsible for the perception of colour through the use of a range of opsins, as well as high-acuity vision used for tasks such as reading. A third type of light-sensing cell, the photosensitive ganglion cell, is important for entrainment of circadian rhythms and reflexive responses such as the pupillary light reflex. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses that are sent to various visual centres of the brain through the fibres of the optic nerve. Neural signals from the rods and cones undergo processing by other neurons, whose output takes the form of action potentials in retinal ganglion cells whose axons form the optic nerve. Several important features of visual perception can be traced to the retinal encoding and processing of light. In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, specifically the embryonic diencephalon; thus, the retina is considered part of the central nervous system (CNS) and is actually brain tissue. It is the only part of the CNS that can be visualized noninvasively. Much like the rest of the brain is isolated from the vasular system via the blood–brain barrier, the retina is similarly protected by the blood–retinal barrier.

ChatGPTRate this definition:0.0 / 0 votes

1. retina

   The retina is a thin layer of light-sensitive tissue located at the back of the eye that contains cells responsible for converting light rays into impulses. These impulses are then sent to the brain through the optic nerve, enabling visual perception. It is essential to the complex process of sight.

Webster DictionaryRate this definition:1.0 / 1 vote

1. Retinanoun

   the delicate membrane by which the back part of the globe of the eye is lined, and in which the fibers of the optic nerve terminate. See Eye

2. Etymology: [NL., from L. rete a net. Cf. Reticule.]

WikidataRate this definition:0.0 / 0 votes

1. Retina

   The vertebrate retina is a light-sensitive layer of tissue, lining the inner surface of the eye. The optics of the eye create an image of the visual world on the retina, which serves much the same function as the film in a camera. Light striking the retina initiates a cascade of chemical and electrical events that ultimately trigger nerve impulses. These are sent to various visual centres of the brain through the fibres of the optic nerve. In vertebrate embryonic development, the retina and the optic nerve originate as outgrowths of the developing brain, so the retina is considered part of the central nervous system and is actually brain tissue. It is the only part of the CNS that can be visualized non-invasively. The retina is a layered structure with several layers of neurons interconnected by synapses. The only neurons that are directly sensitive to light are the photoreceptor cells. These are mainly of two types: the rods and cones. Rods function mainly in dim light and provide black-and-white vision, while cones support daytime vision and the perception of colour. A third, much rarer type of photoreceptor, the photosensitive ganglion cell, is important for reflexive responses to bright daylight.

Chambers 20th Century DictionaryRate this definition:0.0 / 0 votes

1. Retina

   ret′i-na, n. the innermost coating of the eye, consisting of a fine network of optic nerves.—adj. Ret′inal, pertaining to the retina of the eye.—n. Retinī′tis, inflammation of the retina. [Fr.,—L. rete, a net.]

The Nuttall EncyclopediaRate this definition:0.0 / 0 votes

1. Retina

   a retiform expansion of the sensatory nerves, which receives the impression that gives rise to vision, or visual perception.

U.S. National Library of MedicineRate this definition:0.0 / 0 votes

1. 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.

Editors ContributionRate this definition:0.0 / 0 votes

1. retina

   A facet of the mechanism of an eye.

   Any animal, insect or human that has an eye has a retina that is part of the mechanism that enables them to see.

   
   

   Submitted by MaryC on February 2, 2020  

EntomologyRate this definition:0.0 / 0 votes

1. Retina

   that portion of the eye upon which the image is formed.

Matched Categories

1. • Membrane

Anagrams for retina »

1. retain

2. tin ear

3. nerita

4. ratine

5. tanier

How to pronounce retina?

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How to say retina in sign language?

Numerology

1. Chaldean Numerology

   The numerical value of retina in Chaldean Numerology is: 9

2. Pythagorean Numerology

   The numerical value of retina in Pythagorean Numerology is: 4

Examples of retina in a Sentence

1. Emily Chew:

   The retina is an extension of the brain, a third of your brain functions for vision and the retina lines the eyeball and travels back via an optic nerve all the way to the brain.

2. Phil Schiller:

   Far more than on any iOS device before. In fact, that’s even more pixels than a 15-inch MacBook with Retina display.

3. Christopher Quinn:

   When you look directly at the sun, the intensity of the light and the focus of the light is so great on the retina that it can cook it, if the exposure is great enough, that can and will lead to permanent reduction in vision and even blindness.

4. Shreya Prabhu:

   They’ll do things like check pupils, how well they seem to see with each eye, do an external exam and look for a red reflux in the retina… that (red eye) when people take pictures, if you don’t see that red spot in the center of the eye, there could be something in the eye like a cataract or other things obscuring that.

5. Maya Koronyo-Hamaoui:

   These changes in the retina correlated with changes in parts of the brain called the entorhinal and temporal cortices, a hub for memory, navigation and the perception of time.

Popularity rank by frequency of use

References

1. ^ Princeton's WordNet
   http://wordnetweb.princeton.edu/perl/webwn?s=retina
2. ^ Wiktionary
   https://en.wiktionary.org/wiki/Retina
3. ^ Wikipedia
   https://en.wikipedia.org/wiki/Retina
4. ^ ChatGPT
   https://chat.openai.com
5. ^ Webster Dictionary
   https://www.merriam-webster.com/dictionary/retina
6. ^ Wikidata
   https://www.wikidata.org/w/index.php?search=retina
7. ^ Chambers 20th Century Dictionary
   https://www.gutenberg.org/files/37683/37683-h/37683-h.htm#:~:text=retina
8. ^ The Nuttall Encyclopedia
   https://www.gutenberg.org/cache/epub/12342/pg12342-images.html#Retina
9. ^ Entomology
   https://www.gutenberg.org/files/22748/22748-h/22748-h.htm#:~:text=retina