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15 Cards in this Set
- Front
- Back
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Retinal landmarks
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Fovea: only cone photoreceptor
Optic disc: blind spot bc no photoreceptors, vasculature enter/exit eye |
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Blood supply via
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Opthalamic a which splits into central retinal & post. ciliary a
No vasculature to lens & cornea |
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Aqueous humor
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Ultrafiltrate of blood
Reabsorbed by trabecular meshwork & canal of schlemm Dec outflow of humor causes glaucoma |
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What are the fxns of the pigment epi cells?
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1. tight jxns for BBB
2. cells collect garbage 3. protect photoreceptors |
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Glial cells of retina
Control microenvironment Take excess glutamate & turn into non-toxic glutamine |
Muller cells
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Highly sensitive to low levels of light.
High convergence Low spatial resolution (bc loc not knowns) |
Rods
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For bright conditions
Low convergence 1:1 High spatial resolution Low sensitivity (takes 100's of photons) |
Cones
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Phototransduction in dark
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High cGMP which Na levels are sensitive to causing depolarization
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Phototransduction in light
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Stimulated by rhodopsin
Activates G-protein causing inc. cGMP PDE Na channels close Hyperpolarization |
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Depolarization means
Hyperpolarization means |
Release Neurotransmitters
Retain Neurotransmitters |
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Which, either rods/cones, have an intermediate step involving amacrine cells and so therefore is an indirect method to depolarizing ganglion cells?
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Rods
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When visual stimulus present results in change in firing rate
Only bipolar & ganglion cells involved Able to see contrast/edges |
Recpetive fields
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Deals with temporal modulation
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Amacrine
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Types of ganglion cells
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1. Parasol
2. Midget cells 3. Small-field bistratified cells |
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What part of the visual system travels ipsilateral?
...contralateral? |
Temporal
Nasal |
