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5 Cards in this Set
- Front
- Back
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Rod
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Black and white
High sensitivity (night vision, more photo-pigment, high amplification, saturate in daylight) Low temporal resolution (slow response, long integration time) More sensitive to scattered light |
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Rod system
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Low acuity: high convergent retinal pathways
Not in the central fovea Achromatic |
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Cone
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Colors detected by three types
Low sensitivity (day vision, less photopigment, less amplification, saturate only in intense light) High temporal resolution (fast response, short integration time) More sensitive to scattered light |
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Cone system
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High acuity (less convergent retinal pathways)
Concentrated in fovea Chromatic (3 types of cones are sensitive to a different part of the visible spectrum) |
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Explain the photoreceptor response to light
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The photoreceptor response to light decrease cGMP concentration and close ion channels. This hyperpolarizes the photoreceptor and releases glutamate. Glutamate can hyperpolarize or depolarize other neurons.
Increase in cGMP will open the ion channel (Na+ and Ca2+ in) : Dark current Decrease in cGMP will close the ion channel The whole process involves transducin, phosphodiesterase and cGMP when rhopsodin (which is composed of retinal or vitamin A and opsin) is hit by the light |
