Difference between revisions of "The Eye and Retina"
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| − | + | [[File:EyeDrawing.jpg | thumb| right| 500px | A drawing of a section through the human eye with a schematic enlargement of the retina. <ref name="Kolb">Kolb, Helga, Nelson, Ralph, Fernandez, Eduardo, Jones, Bryan, The Organization of the Retina and Visual System, Simple Anatomy of the Retina. url=http://webvision.med.utah.edu/book/part-i-foundations/simple-anatomy-of-the-retina/</ref>]] | |
| + | The retina is a light-sensitive layer of tissue that lines the rear surface of the eye. Light from one's visual field passes through the eye and projects onto the retina to create an image. Subsequently, retinal neurons detect this image, which initiates a cascade of biochemical and electrical processing that is sent through the optic nerve and eventually to the visual cortex of the brain. These biochemical and electrical signals provide the basis for vision. | ||
| + | ==All the Parts== | ||
=== Cornea === | === Cornea === | ||
Transparent surface of the eye that covers the pupil and iris | Transparent surface of the eye that covers the pupil and iris | ||
| Line 59: | Line 61: | ||
Muscles insert into the sclera and move the eyeball and keep image focused on the fovea | Muscles insert into the sclera and move the eyeball and keep image focused on the fovea | ||
| − | 6 main muscles: | + | 6 main muscles: <br> |
| − | superior rectus | + | superior rectus<br> |
| − | inferior rectus | + | inferior rectus<br> |
| − | medial rectus | + | medial rectus<br> |
| − | lateral rectus | + | lateral rectus<br> |
| − | superior oblique | + | superior oblique<br> |
| − | inferior oblique | + | inferior oblique<br> |
medical: lazy eye, etc. | medical: lazy eye, etc. | ||
== Anatomy of the human retina == | == Anatomy of the human retina == | ||
| − | + | [[File:NormalRetina.gif | thumb | right | 300px | A diagram showing the locations of the Optic cube and disc, Macula, Fovea, veins, and arteries. <ref name="Kolb"></ref>]] | |
Funduscopic examination of the retina | Funduscopic examination of the retina | ||
| − | |||
=== Optic cup and disc === | === Optic cup and disc === | ||
| − | retinal ganglion axons converge here | + | retinal ganglion axons converge here<br> |
| − | central area are retinal artery and veins | + | central area are retinal artery and veins <br> |
| − | “Blind spot” | + | “Blind spot”<br> |
=== Macula and Fovea === | === Macula and Fovea === | ||
| − | high quantity of ganglion cells and cones for visual acuity and color perception | + | high quantity of ganglion cells and cones for visual acuity and color perception<br> |
Interactive site: | Interactive site: | ||
http://www.aao.org/theeyeshaveit/anatomy/normal-fundus.cfm | http://www.aao.org/theeyeshaveit/anatomy/normal-fundus.cfm | ||
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| − | |||
| − | |||
=== 10 histological layers of the retina === | === 10 histological layers of the retina === | ||
| Line 90: | Line 88: | ||
Retinal pigment epithelium<br> | Retinal pigment epithelium<br> | ||
Single layer of hexagonal cells<br> | Single layer of hexagonal cells<br> | ||
| − | Located between the choroid and the photoreceptor layer | + | Located between the choroid and the photoreceptor layer<br> |
| − | Forms a blood-retina barrier with tight junctions with the choroid | + | Forms a blood-retina barrier with tight junctions with the choroid<br> |
| − | It is not firmly attached to the the neural aspect of the retina (photoreceptor layer) | + | It is not firmly attached to the the neural aspect of the retina (photoreceptor layer)<br> |
| − | medical: a potential site of retinal detachment | + | medical: a potential site of retinal detachment<br> |
Photoreceptor layer<br> | Photoreceptor layer<br> | ||
| − | Composed of rods and cones | + | Composed of rods and cones<br> |
| − | Outer limiting “membrane” | + | Outer limiting “membrane”<br> |
| − | Site of connection between photoreceptors and Müller cells | + | Site of connection between photoreceptors and Müller cells<br> |
Outer nuclear layer<br> | Outer nuclear layer<br> | ||
| − | Nuclei of photoreceptor cells | + | Nuclei of photoreceptor cells<br> |
Outer plexiform layer<br> | Outer plexiform layer<br> | ||
| − | Photoreceptor fibers | + | Photoreceptor fibers<br> |
| − | Bipolar cell dendrites | + | Bipolar cell dendrites<br> |
“Two important synaptic interactions that occur at the outer plexiform layer are: | “Two important synaptic interactions that occur at the outer plexiform layer are: | ||
the splitting of the visual signal into two separate channels of information flow, one for detecting objects lighter than background and one for detecting objects darker that background | the splitting of the visual signal into two separate channels of information flow, one for detecting objects lighter than background and one for detecting objects darker that background | ||
the instillation of pathways to create simultaneous contrast of visual objects | the instillation of pathways to create simultaneous contrast of visual objects | ||
| − | In the first synaptic interactions, the channels of information flow are known as the basis of successive contrast, or ON and OFF pathways, respectively, whereas the second interaction puts light and dark boundaries in simultaneous contrast and forms a receptive field structure, with a center contrasted to an inhibitory surround.” | + | In the first synaptic interactions, the channels of information flow are known as the basis of successive contrast, or ON and OFF pathways, respectively, whereas the second interaction puts light and dark boundaries in simultaneous contrast and forms a receptive field structure, with a center contrasted to an inhibitory surround.”<br> |
| − | Inner nuclear layer | + | Inner nuclear layer<br> |
| − | Bipolar cell nuclei | + | Bipolar cell nuclei<br> |
| − | Horizontal cells | + | Horizontal cells<br> |
| − | Amacrine cells | + | Amacrine cells<br> |
| − | Interplexiform cells | + | Interplexiform cells<br> |
| − | Muller cells | + | Muller cells<br> |
| − | Inner plexiform layer | + | Inner plexiform layer<br> |
| − | Presynaptic dendrites of bipolar cells (axons) | + | Presynaptic dendrites of bipolar cells (axons)<br> |
| − | Postsynaptic dendrites of ganglion cells | + | Postsynaptic dendrites of ganglion cells<br> |
| − | Amacrine cell dendrites | + | Amacrine cell dendrites<br> |
| − | Ganglion cell layer | + | Ganglion cell layer<br> |
| − | Nerve fiber layer | + | Nerve fiber layer<br> |
| − | Axons of Ganglion cells | + | Axons of Ganglion cells<br> |
| − | Inner limiting “membrane” | + | Inner limiting “membrane”<br> |
| − | Ends of Muller cells | + | Ends of Muller cells<br> |
| Line 127: | Line 125: | ||
Image credit: | Image credit: | ||
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| − | |||
http://www.ncbi.nlm.nih.gov/books/NBK10885/figure/A740/?report=objectonly | http://www.ncbi.nlm.nih.gov/books/NBK10885/figure/A740/?report=objectonly | ||
Reference credit: | Reference credit: | ||
| Line 138: | Line 134: | ||
=== Cells of the retina === | === Cells of the retina === | ||
| − | Retinal Pigment Epithelium | + | Retinal Pigment Epithelium<br> |
| − | http://www.retinalmicroscopy.com/pigment.html | + | http://www.retinalmicroscopy.com/pigment.html<br> |
| − | Contain pigment granules and absorbs scattered light | + | Contain pigment granules and absorbs scattered light<br> |
| − | Regenerates 11-cis-retinal the chromophore used in photoreceptors | + | Regenerates 11-cis-retinal the chromophore used in photoreceptors<br> |
| − | Responds to oxidative stress | + | Responds to oxidative stress<br> |
| − | Clearing up shed discs of rods and cones | + | Clearing up shed discs of rods and cones<br> |
| − | Blood-retinal barrier functions | + | Blood-retinal barrier functions<br> |
| − | Medical: | + | Medical: <br> |
| − | albinos lack pigment in this layer | + | albinos lack pigment in this layer<br> |
| − | macular degeneration | + | macular degeneration<br> |
| − | retinitis pigmentosa | + | retinitis pigmentosa<br> |
| − | Photoreceptors | + | Photoreceptors <br> |
| − | Segments (outer, inner, fiber) | + | Segments (outer, inner, fiber)<br> |
| − | http://www.retinalmicroscopy.com/photoreceptors.html | + | http://www.retinalmicroscopy.com/photoreceptors.html<br> |
| − | Rods: role in peripheral vision, night vision | + | Rods: role in peripheral vision, night vision<br> |
| − | contain rhodopsins | + | contain rhodopsins<br> |
| − | more rods than cones in the retina | + | more rods than cones in the retina<br> |
| − | no rods in fovea = night blind | + | no rods in fovea = night blind<br> |
| − | more sensitive to dim light | + | more sensitive to dim light<br> |
| − | increases in quantity peripherally | + | increases in quantity peripherally<br> |
| − | Cones: role in visual acuity and color vision | + | Cones: role in visual acuity and color vision<br> |
| − | concentrated at center (fovea and macula) and less at periphery | + | concentrated at center (fovea and macula) and less at periphery<br> |
| − | contains different types of opsins | + | contains different types of opsins<br> |
| − | 3 types - each absorb one of 3 colors of light | + | 3 types - each absorb one of 3 colors of light <br> |
| − | S-cone: short wavelength - blue | + | S-cone: short wavelength - blue<br> |
| − | M-cone: medium wavelength - green | + | M-cone: medium wavelength - green<br> |
| − | L cone: long wavelength -red | + | L cone: long wavelength -red<br> |
=== Medical === | === Medical === | ||
| − | if issues with one or more cones types - colorblindness | + | if issues with one or more cones types - colorblindness<br> |
| − | most common - can’t differentiate red and green | + | most common - can’t differentiate red and green<br> |
| − | usually X-linked recessive - affects men more | + | usually X-linked recessive - affects men more<br> |
| − | http://www.colourblindawareness.org/colour-blindness/ | + | http://www.colourblindawareness.org/colour-blindness/<br> |
| − | Ishihara test | + | Ishihara test<br> |
| − | Vitamin A deficiency | + | Vitamin A deficiency<br> |
| − | Retinitis pigmentosa | + | Retinitis pigmentosa<br> |
| − | Dark adaptation (discuss in the future) | + | Dark adaptation (discuss in the future)<br> |
| − | Phototransduction (discuss somewhere else in the future) | + | Phototransduction (discuss somewhere else in the future)<br> |
== Cells of the Retina == | == Cells of the Retina == | ||
=== Bipolar cells === | === Bipolar cells === | ||
| − | http://www.retinalmicroscopy.com/bipolar.html | + | http://www.retinalmicroscopy.com/bipolar.html<br> |
| − | Several types | + | Several types<br> |
| − | rod-specific bipolar cells (1) | + | rod-specific bipolar cells (1)<br> |
| − | cone-specific bipolar cells (10) | + | cone-specific bipolar cells (10)<br> |
| − | Transmit signals from photoreceptor cells to ganglion cells | + | Transmit signals from photoreceptor cells to ganglion cells<br> |
| − | processes/neurites are called dendrites | + | processes/neurites are called dendrites<br> |
| − | ON and OFF layers | + | ON and OFF layers<br> |
need to explain this* | need to explain this* | ||
“We know that a photoreceptor neurotransmitter (which is glutamate, see Dowling (24) and Massey (25) for reviews) is released in the dark in the vertebrate retina (26). Thus, the photoreceptor, whether it be rod or cone, is in a depolarized state in the dark. On light stimulation, the photoreceptor responds with a hyperpolarization; transmitter release ceases, but the postsynaptic bipolar cells respond with either hyperpolarization or depolarization of their membranes. The hyperpolarizing type of bipolar cell is called an OFF-center cell, whereas the depolarizing bipolar cell is called an ON-center cell (27, 28).” | “We know that a photoreceptor neurotransmitter (which is glutamate, see Dowling (24) and Massey (25) for reviews) is released in the dark in the vertebrate retina (26). Thus, the photoreceptor, whether it be rod or cone, is in a depolarized state in the dark. On light stimulation, the photoreceptor responds with a hyperpolarization; transmitter release ceases, but the postsynaptic bipolar cells respond with either hyperpolarization or depolarization of their membranes. The hyperpolarizing type of bipolar cell is called an OFF-center cell, whereas the depolarizing bipolar cell is called an ON-center cell (27, 28).” | ||
=== Ganglion cells === | === Ganglion cells === | ||
| − | http://www.retinalmicroscopy.com/ganglion.html | + | http://www.retinalmicroscopy.com/ganglion.html<br> |
| − | Bipolar cells contact both dendrites and soma of ganglion cells | + | Bipolar cells contact both dendrites and soma of ganglion cells<br> |
| − | Axons → forms optic nerve (CN II) | + | Axons → forms optic nerve (CN II)<br> |
| − | Association neurons (interneurons) | + | Association neurons (interneurons)<br> |
| − | Modify synaptic transmission in retina | + | Modify synaptic transmission in retina<br> |
=== Horizontal cells === | === Horizontal cells === | ||
| − | http://www.retinalmicroscopy.com/horizontal.html | + | http://www.retinalmicroscopy.com/horizontal.html<br> |
| − | located between OPL and INL | + | located between OPL and INL<br> |
| − | 3 types on human retina (HI, HII, HIII) | + | 3 types on human retina (HI, HII, HIII)<br> |
| − | dendrites contact synaptic terminals of photoreceptor cells and with the dendrites of bipolar cells, which they inhibit | + | dendrites contact synaptic terminals of photoreceptor cells and with the dendrites of bipolar cells, which they inhibit<br> |
=== Amacrine cells === | === Amacrine cells === | ||
| − | http://www.retinalmicroscopy.com/amacrine.html | + | http://www.retinalmicroscopy.com/amacrine.html<br> |
| − | located between INL and IPL | + | located between INL and IPL<br> |
| − | all dendrites emerge from same side of the cell to branch out and terminate in synaptic complexes between bipolar, ganglion, etc cells | + | all dendrites emerge from same side of the cell to branch out and terminate in synaptic complexes between bipolar, ganglion, etc cells<br> |
| − | thought to lack axons. | + | thought to lack axons.<br> |
| − | some morphologies might have axons but do not leave retina | + | some morphologies might have axons but do not leave retina<br> |
| − | Interplexiform cells | + | Interplexiform cells<br> |
| − | post-synaptic to amacrine cells and pre-synaptic to horizontal and bipolar cells | + | post-synaptic to amacrine cells and pre-synaptic to horizontal and bipolar cells<br> |
| − | feedback loop | + | feedback loop<br> |
=== Neuroglial cells === | === Neuroglial cells === | ||
| − | cells of Müller - principal glial cells of the retina | + | cells of Müller - principal glial cells of the retina<br> |
| − | http://www.retinalmicroscopy.com/glial.html | + | http://www.retinalmicroscopy.com/glial.html<br> |
| − | extend through the whole thickness of the retina | + | extend through the whole thickness of the retina<br> |
| − | Provide architectual support | + | Provide architectual support<br> |
| − | supporting role and other functions (communications?) | + | supporting role and other functions (communications?)<br> |
| − | Astroglia | + | Astroglia<br> |
| − | Microglia | + | Microglia<br> |
Image credit: | Image credit: | ||
| Line 239: | Line 235: | ||
http://www.ncbi.nlm.nih.gov/books/NBK11536/ | http://www.ncbi.nlm.nih.gov/books/NBK11536/ | ||
http://www.ncbi.nlm.nih.gov/books/NBK11516/ | http://www.ncbi.nlm.nih.gov/books/NBK11516/ | ||
| + | |||
| + | ==References== | ||
| + | <references /> | ||
Revision as of 16:19, 12 June 2014
The retina is a light-sensitive layer of tissue that lines the rear surface of the eye. Light from one's visual field passes through the eye and projects onto the retina to create an image. Subsequently, retinal neurons detect this image, which initiates a cascade of biochemical and electrical processing that is sent through the optic nerve and eventually to the visual cortex of the brain. These biochemical and electrical signals provide the basis for vision.
All the Parts
Cornea
Transparent surface of the eye that covers the pupil and iris First refractive surface that light goes through on its way to the retina 3 layers (epithelium, stroma, endothelium) 5, possibly 6 layers, (Epithelium, Bowmans layer, Stroma, Dua’s layer (Discovered last year, still awaiting official confirmation), Descemet’s membrane, endothelium) medical: corneal abrasions, ametropia (any refractive area can be cause), etc
Iris
Muscular diaphragm that controls the size of the pupil and amount of light that can enter the eye Color of the iris is due to quantity and type of melanin
Pupil
Aperture that allows the light to enter the eye
Lens
Second refractive surface that light goes through on its way to the retina tidbit: no blood supply to the lens medical: cataracts, presbyopia
Ciliary body
Ciliary muscle (with zonule fibers) Changes the shape of the lens and allows for accommodation
Ciliary epithelium
Makes the aqueous fluid that fills the anterior and posterior chambers Three fluid chambers Anterior Between cornea and iris Posterior Between iris and lens Vitreous Between lens and retina Humours (hehehe)
Aqueous
Clear, watery fluid that supplies nutrients to the structures it surrounds. Movement of aqueous humor is from posterior chamber to anterior chamber through the pupil. Drainage out of the anterior chamber via canal of Schlemm and trabecular meshwork into venous system. The equilibrium maintains appropriate intra-ocular pressure. medical: glaucoma (open and close angle)
Vitreous
thick, gel-like fluid that maintains the shape of the eye 80% of the volume of the eye medical: floaters, retinal detachment Three layers of the eye sphere (outside to inside)
Sclera
Outermost layer of the globe White fibrous layer that becomes transparent at anterior part of the eye and forms the cornea
Choroid
Middle layer between sclera and retina It is the vascular layer and source of oxygen and nutrients to the outer layers of the retina (photoreceptor layer) Bruch’s membrane
Retina
Inner layer of the globe Light-sensitive neurons transmit visual signals Macula and Fovea Site of high acuity of vision Optic nerve (add this here?) Retinal arteries and veins (add this here?)
Interactive site: http://www.aao.org/theeyeshaveit/anatomy/section-eye.cfm
Extraocular muscles of the eye
Muscles insert into the sclera and move the eyeball and keep image focused on the fovea
6 main muscles:
superior rectus
inferior rectus
medial rectus
lateral rectus
superior oblique
inferior oblique
medical: lazy eye, etc.
Anatomy of the human retina
Funduscopic examination of the retina
Optic cup and disc
retinal ganglion axons converge here
central area are retinal artery and veins
“Blind spot”
Macula and Fovea
high quantity of ganglion cells and cones for visual acuity and color perception
Interactive site:
http://www.aao.org/theeyeshaveit/anatomy/normal-fundus.cfm
10 histological layers of the retina
http://www.retinalmicroscopy.com/species.html
http://www.retinalmicroscopy.com/movies.html
Retinal pigment epithelium
Single layer of hexagonal cells
Located between the choroid and the photoreceptor layer
Forms a blood-retina barrier with tight junctions with the choroid
It is not firmly attached to the the neural aspect of the retina (photoreceptor layer)
medical: a potential site of retinal detachment
Photoreceptor layer
Composed of rods and cones
Outer limiting “membrane”
Site of connection between photoreceptors and Müller cells
Outer nuclear layer
Nuclei of photoreceptor cells
Outer plexiform layer
Photoreceptor fibers
Bipolar cell dendrites
“Two important synaptic interactions that occur at the outer plexiform layer are:
the splitting of the visual signal into two separate channels of information flow, one for detecting objects lighter than background and one for detecting objects darker that background
the instillation of pathways to create simultaneous contrast of visual objects
In the first synaptic interactions, the channels of information flow are known as the basis of successive contrast, or ON and OFF pathways, respectively, whereas the second interaction puts light and dark boundaries in simultaneous contrast and forms a receptive field structure, with a center contrasted to an inhibitory surround.”
Inner nuclear layer
Bipolar cell nuclei
Horizontal cells
Amacrine cells
Interplexiform cells
Muller cells
Inner plexiform layer
Presynaptic dendrites of bipolar cells (axons)
Postsynaptic dendrites of ganglion cells
Amacrine cell dendrites
Ganglion cell layer
Nerve fiber layer
Axons of Ganglion cells
Inner limiting “membrane”
Ends of Muller cells
Image credit:
http://www.ncbi.nlm.nih.gov/books/NBK10885/figure/A740/?report=objectonly
Reference credit:
http://www.ncbi.nlm.nih.gov/books/NBK10885/
http://www.ncbi.nlm.nih.gov/books/NBK11533/
http://www.ncbi.nlm.nih.gov/books/NBK54392/
http://www.ncbi.nlm.nih.gov/books/NBK11518/
http://www.ncbi.nlm.nih.gov/books/NBK11536/
Cells of the retina
Retinal Pigment Epithelium
http://www.retinalmicroscopy.com/pigment.html
Contain pigment granules and absorbs scattered light
Regenerates 11-cis-retinal the chromophore used in photoreceptors
Responds to oxidative stress
Clearing up shed discs of rods and cones
Blood-retinal barrier functions
Medical:
albinos lack pigment in this layer
macular degeneration
retinitis pigmentosa
Photoreceptors
Segments (outer, inner, fiber)
http://www.retinalmicroscopy.com/photoreceptors.html
Rods: role in peripheral vision, night vision
contain rhodopsins
more rods than cones in the retina
no rods in fovea = night blind
more sensitive to dim light
increases in quantity peripherally
Cones: role in visual acuity and color vision
concentrated at center (fovea and macula) and less at periphery
contains different types of opsins
3 types - each absorb one of 3 colors of light
S-cone: short wavelength - blue
M-cone: medium wavelength - green
L cone: long wavelength -red
Medical
if issues with one or more cones types - colorblindness
most common - can’t differentiate red and green
usually X-linked recessive - affects men more
http://www.colourblindawareness.org/colour-blindness/
Ishihara test
Vitamin A deficiency
Retinitis pigmentosa
Dark adaptation (discuss in the future)
Phototransduction (discuss somewhere else in the future)
Cells of the Retina
Bipolar cells
http://www.retinalmicroscopy.com/bipolar.html
Several types
rod-specific bipolar cells (1)
cone-specific bipolar cells (10)
Transmit signals from photoreceptor cells to ganglion cells
processes/neurites are called dendrites
ON and OFF layers
need to explain this*
“We know that a photoreceptor neurotransmitter (which is glutamate, see Dowling (24) and Massey (25) for reviews) is released in the dark in the vertebrate retina (26). Thus, the photoreceptor, whether it be rod or cone, is in a depolarized state in the dark. On light stimulation, the photoreceptor responds with a hyperpolarization; transmitter release ceases, but the postsynaptic bipolar cells respond with either hyperpolarization or depolarization of their membranes. The hyperpolarizing type of bipolar cell is called an OFF-center cell, whereas the depolarizing bipolar cell is called an ON-center cell (27, 28).”
Ganglion cells
http://www.retinalmicroscopy.com/ganglion.html
Bipolar cells contact both dendrites and soma of ganglion cells
Axons → forms optic nerve (CN II)
Association neurons (interneurons)
Modify synaptic transmission in retina
Horizontal cells
http://www.retinalmicroscopy.com/horizontal.html
located between OPL and INL
3 types on human retina (HI, HII, HIII)
dendrites contact synaptic terminals of photoreceptor cells and with the dendrites of bipolar cells, which they inhibit
Amacrine cells
http://www.retinalmicroscopy.com/amacrine.html
located between INL and IPL
all dendrites emerge from same side of the cell to branch out and terminate in synaptic complexes between bipolar, ganglion, etc cells
thought to lack axons.
some morphologies might have axons but do not leave retina
Interplexiform cells
post-synaptic to amacrine cells and pre-synaptic to horizontal and bipolar cells
feedback loop
Neuroglial cells
cells of Müller - principal glial cells of the retina
http://www.retinalmicroscopy.com/glial.html
extend through the whole thickness of the retina
Provide architectual support
supporting role and other functions (communications?)
Astroglia
Microglia
Image credit: http://www.as.miami.edu/chemistry/2008-1-MDC/2085/Chap-17_New/chap17_files/image018.jpg http://media.learn.uci.edu/cat/media/OC08/11004/OC0811004_3RetinalTypes.jpg http://www.ncbi.nlm.nih.gov/books/NBK11518/figure/A215/?report=objectonly http://www.ncbi.nlm.nih.gov/books/NBK11536/figure/ch06ipl.F9/?report=objectonly http://www.as.miami.edu/chemistry/2008-1-MDC/2085/Chap-17_New/chap17_files/image024.jpg http://www.ncbi.nlm.nih.gov/books/NBK11518/figure/A222/?report=objectonly http://www.ncbi.nlm.nih.gov/books/NBK11518/figure/A226/?report=objectonly http://www.ncbi.nlm.nih.gov/books/NBK11536/figure/ch06ipl.F6/?report=objectonly http://www.ncbi.nlm.nih.gov/books/NBK11516/figure/ch09glia.F2/?report=objectonly
Reference credit: http://www.ncbi.nlm.nih.gov/books/NBK54392/ http://www.ncbi.nlm.nih.gov/books/NBK11522/ http://www.as.miami.edu/chemistry/2008-1-MDC/2085/Chap-17_New/chap17.htm http://www.ncbi.nlm.nih.gov/books/NBK11518/ http://www.ncbi.nlm.nih.gov/books/NBK11536/ http://www.ncbi.nlm.nih.gov/books/NBK11516/
References
- ↑ 1.0 1.1 Kolb, Helga, Nelson, Ralph, Fernandez, Eduardo, Jones, Bryan, The Organization of the Retina and Visual System, Simple Anatomy of the Retina. url=http://webvision.med.utah.edu/book/part-i-foundations/simple-anatomy-of-the-retina/
