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21 Cards in this Set
- Front
- Back
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What is the response to light stimulus from rods and cones ?
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HYPERPOLARIZED
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T or F
Rods and cones have a graded response? |
True
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What does it mean when it is said that rods and cones have a graded response?
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The more intense the light, the more hyperpolarized the cell becomes
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What is the chance that the appropriate color passing thru the retina will be captured?
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50%
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T or F
The photon is absorbed by the protein itself |
False-
It is absorbed by vitamin A bound to a protein |
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After the photon hits the vitamin A bound to a protein, what happens next?
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Activation of G-Protein
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How is G-protein activated?
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thru the membrane protein, which has vitamin A bound to it and absorbs photons
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What does light do to photoreceptors?
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Hyperpolarizes
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What happens when you have a reduction in cGMP?
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Nonselective ion channels in the surface of the membrane close.
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When nonselective ion channels in the surface of the membrane close, what happens to the cell?
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Hyper-polarizing
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T or F
dark photoreceptors have a high concentration of cGMP |
True
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If there are many channels opened in the dark is the membrane depolarized or hyperpolarized?
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Depolarized
Light hyperpolarizes |
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what inhibits On-center bipolar cells?
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glutamate
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What effect does glutamate have on OFF-center bipolar cells?
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excites it
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T or F
Photoreceptors are hyperpolarized by light |
TRUE
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if a photoreceptor is hyperplarixed by light what is the result in the neurotransmitter?
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Less nerotransmitter is released
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What chemical do photoreceptors release?
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glutamate
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T or F
OFF-center = excited |
T
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T or F
ON-center=inhibited |
true
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where do bipolar cells always make excitatory synapeses?
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ganglion cells
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What is the function of horizontal cells?
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Makes inhibitory synapeses on neighboring photoreceptors. (behaves like excitatory receptor for glutamate)
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