1. After light hits a photoreceptor, what happens to cause hyperpolarization (repolarization of the photoreceptor membrane)?...

 

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1. After light hits a photoreceptor, what happens to cause "hyperpolarization" (repolarization of the photoreceptor membrane)? 2. 4. A. Cyclic AMP inhibits Ca2+ channels B. Na+, K+-ATPase is activated 5. C. Calcium levels rise and K* channels open in response to Ca²+-dependent phosphorylation D. Cyclic AMP levels rise and inward Cl- current is blocked E. Cyclic GMP levels fall and Na+ channels close 3. Off-center responses in the retina (in On-center, Off-surround receptive fields) involve which of the following target neurotransmitter receptors on bipolar cells? A. A-type GABA receptors (GABAARS) Ganglion cells in the retina: A. are hyperpolarized in the dark B. send action potentials to the lateral geniculate nucleus C. are activated by acetylcholine D. synapse on retinal bipolar cells E. cause lateral inhibition via GABA B. Metabotropic-type glutamate receptors (mGluRs) C. Muscarinic acetylcholine receptors (mAChRs) D. Ionotropic-type glutamate receptors (iGluRs) E. Nicotinic acetylcholine receptors (nAChRs) An orientation column in the visual cortex refers to: A. A vertical block receiving input (signals) onto simple cells from either the upper or the lower half of each retina B. A cylindrical subregion receiving input (signals) from both retinas onto complex cells coding for movement in the visual field C. A vertical block receiving input (signals) onto simple cells coding for the slope of a bar of light out in the visual hemi-field D. A vertical block receiving input (signals) onto complex cells from either the left or the right hemi-retina E. A semi-circular subregion that orients the rest of the visual cortex to visual input Simple cells in the visual cortex are activated best by retina exposure to: A. Bars of light of a particular orientation and position B. Boxes of light of a particular orientation but not a precise position C. Simple circles of light D. Simple black squares E. Diffuse, flickering light 1. After light hits a photoreceptor, what happens to cause "hyperpolarization" (repolarization of the photoreceptor membrane)? 2. 4. A. Cyclic AMP inhibits Ca2+ channels B. Na+, K+-ATPase is activated 5. C. Calcium levels rise and K* channels open in response to Ca²+-dependent phosphorylation D. Cyclic AMP levels rise and inward Cl- current is blocked E. Cyclic GMP levels fall and Na+ channels close 3. Off-center responses in the retina (in On-center, Off-surround receptive fields) involve which of the following target neurotransmitter receptors on bipolar cells? A. A-type GABA receptors (GABAARS) Ganglion cells in the retina: A. are hyperpolarized in the dark B. send action potentials to the lateral geniculate nucleus C. are activated by acetylcholine D. synapse on retinal bipolar cells E. cause lateral inhibition via GABA B. Metabotropic-type glutamate receptors (mGluRs) C. Muscarinic acetylcholine receptors (mAChRs) D. Ionotropic-type glutamate receptors (iGluRs) E. Nicotinic acetylcholine receptors (nAChRs) An orientation column in the visual cortex refers to: A. A vertical block receiving input (signals) onto simple cells from either the upper or the lower half of each retina B. A cylindrical subregion receiving input (signals) from both retinas onto complex cells coding for movement in the visual field C. A vertical block receiving input (signals) onto simple cells coding for the slope of a bar of light out in the visual hemi-field D. A vertical block receiving input (signals) onto complex cells from either the left or the right hemi-retina E. A semi-circular subregion that orients the rest of the visual cortex to visual input Simple cells in the visual cortex are activated best by retina exposure to: A. Bars of light of a particular orientation and position B. Boxes of light of a particular orientation but not a precise position C. Simple circles of light D. Simple black squares E. Diffuse, flickering light

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1 E Explanation Na channels are kept in the open state by very high levels of resting Na which resul... View the full answer