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20 Cards in this Set
- Front
- Back
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What is hyperopia?
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farsightedness, people can see okay far but not up close because focal point is behind the retina. can be do to the eye being short
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What is myopia?
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nearsightedness. People can see well up close but can't see far because focal point is infront of retina
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What is astigmatism?
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cornea has radius of curvature different in one axis then the other so light is focused in more then one place>> blurred vision
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Ganglion cells send APs to to optic nerve which goes to the thalamus. What do the other cells (ie.bipolar and horizontal) do to transmit signals?
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Use graded potentials
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What are the layers of the retina that light passes through before being phototransduced?
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ganglion cells, bipolar cells (inner cell layer), outer plexiform layer with horizontal cells, outer cell layer with photoreceptors to phototransduce. If any more goes, hits the retinal pigment epithelium
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What is the role of melanin cells in the retinal epithelium?
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supply nutrients and O2 to the photoreceptors, produce trophic factors and reduce light scatter (just like skin), and are responsible for phagocytosing outer segments of rapidly shedding rods
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What are the steps of phototransdxn?
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Light strikes photoreceptors causing retinaldehyde to be isomerized which leads to biochemical events leading to the closure of Na channels and subsequent hyperpolarizing of cell to -60mV
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When in dark adaptation a bright light is flashed, which cells, rods or cones, adapt more quickly?
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Cones (bright light cells)
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What determines the light senstitivty of the three types of cones (red, blue, green)?
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the type of photopigment in the cone, which has a specific absorption spectrum
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What is the mechanism of exudative AMD?
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neovascularization of the subretinal choroidal membrane and detachment of the retinal pigment epithelium and subretinal hemorrages
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What is the mechanism of non-exudative AMD?
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clumps of pigments in the outer retina with focal atrophy of retinal pigment epithelium
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What is the role of melanin cells in the retinal epithelium?
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supply nutrients and O2 to the photoreceptors, produce trophic factors and reduce light scatter (just like skin), and are responsible for phagocytosing outer segments of rapidly shedding rods
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What are the steps of phototransdxn?
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Light strikes photoreceptors causing retinaldehyde to be isomerized which leads to biochemical events leading to the closure of Na channels and subsequent hyperpolarizing of cell to -60mV
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When in dark adaptation a bright light is flashed, which cells, rods or cones, adapt more quickly?
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Cones (bright light cells)
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What determines the light senstitivty of the three types of cones (red, blue, green)?
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the type of photopigment in the cone, which has a specific absorption spectrum
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What is the mechanism of exudative AMD?
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neovascularization of the subretinal choroidal membrane and detachment of the retinal pigment epithelium and subretinal hemorrages
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What is the mechanism of non-exudative AMD?
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clumps of pigments in the outer retina with focal atrophy of retinal pigment epithelium
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What is retinitis pigmentosa? What are abnormal pathological findings in retinitis pigmentosa?
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Mutated genes causes peripheral retina degeneratioin thus affecting rods causing night blindness and tunnel vision. Abnormal findings are black pigment in periph retina and thin blood vessels in head of optic nerve
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What happens in diabetic retinopathy?
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circulation of blood vessels in eyes becomes compromised leading to abnormal angiogenesis causing blindness
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What is the route of the pupillary reflex?
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Light strikes retina causing APs in ganglion cells. APs travel down ganglions in optic tract and decussate at chiasm if nasal. They pass the LGN (do NOT synapse) and go to both EW nuclei in the pretectum of midbrain (superior colliculi). EW nuclei send axons to ciliary gang-- iris sphincter mm and ciliary body
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