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15 Cards in this Set
- Front
- Back
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What initiate the Transduction cascade in the eye?
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rhodopsin (a GPCR)
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What happens when light hits the photoreceptors in the eye?
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during light response cGMP falls, channels close, current decreases
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What is transducin and what does it activate?
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G protein that activates phosphodiasterase which cGMP to GMP and closes Na channel
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How is the GPCR rhodopsin inactivated?
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by phosphorylation and binding of arrestin
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How would mutations in kinase or arrestin impact vision?
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persistent activity of the photoreceptors and delay of the light response (ex: night blindness)
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chromophore molecules change their conformation when light hits. T/F?
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T
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what causes the delay in rod adaptation at night?
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time it takes to pump the chromophore back into the rods and re-associate with the opsin
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What does the decrease of [ca] in the photoreceptor cause?
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Events to counter the effects of light:
1. Decrease gain of rhodopsin 2. speads rhodopsin shut off 3. increase rate of cGMP production 4. increase sensitivity of channels to cGMP |
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what is the difference between photoreceptors and olfactory receptors in terms of signal propagation?
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olfactory receptors have active propagation of signal down the axons
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in an olfactory cell being stimulated, is the current positive or negative? is it going in or out of the cell?
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negative, out
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in an olfactory cell the binding of the stimuls activates the Gprotein which opens/closes the ion channels?
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opens
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in an olfactory cell activation, which of the following molecule is used: cGMP or cAMP
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cAMP
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non-selective ion channels have a reversal potential of...?
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zero
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what is a tensilon test
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Tensilon (Ach esterase inhibitor) is used to diagnose Myasthenia gravis. After the injection, the patient's muscle function improves
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in guillain barre synd, pain and temperature sensations are affected. T/F
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F. Pain and temperature are carried out by unmyelinated azons
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