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Physiology Special Senses eaf682e6

Which of the following best describes the permeability to sodium and potassium in rod cells in response to the light?

A
Decreased sodium permeability, decreased potassium permeability
B
Decreased sodium permeability, increased potassium permeability
C
Decreased sodium permeability, no change in potassium permeability
D
Increased sodium permeability, decreased potassium permeability
High-Yield Explanation
Activated rhodopsin (metarhodopsin II) closes cGMP-gated sodium channels by lowering levels of cGMP; this action decreases sodium permeability. Potassium permeability is not affected.

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