the innermost light-sensitive membrane covering the back wall of the eyeball; it is continuous with the optic nerve
The thin layer of cells at the back of the eyeball where light is converted into neural signals sent to the brain.
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.
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
Etymology: [NL., from L. rete a net. Cf. Reticule.]
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 Dictionary
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 Encyclopedia
a retiform expansion of the sensatory nerves, which receives the impression that gives rise to vision, or visual perception.
U.S. National Library of Medicine
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.
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
The numerical value of retina in Chaldean Numerology is: 9
The numerical value of retina in Pythagorean Numerology is: 4
Examples of retina in a Sentence
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.
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.
The lens seems an interesting concept to provide optical magnification to the retina when required.
There is a standard of care when an eye doctor is expected to perform an eye exam and the eye exam is expected to determine if the patient does or doesn't have things like glaucoma, retina problems, even diabetes can be detected.
Bright light works by stimulating cells in the retina that connect to the hypothalamus, a part of the brain that helps control circadian rhythms.
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Translations for retina
From our Multilingual Translation Dictionary
- شبكية عين, شبكية العينArabic
- Retina, NetzhautGerman
- verkkokalvo, retinaFinnish
- recehártya, retinaHungarian
- 눈의 망막Korean
- netvlies, retinaDutch
- ретина, сетчаткаRussian
- retina, mrežnica, mrežnjačaSerbo-Croatian
- retina, näthinnaSwedish
- ağ tabaka, ağ katTurkish
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