The "dark current" of photoreceptors refers to A) the exit of Na⁺ and Ca²⁺ out of the cell when light is not hitting the cell. B) the entry of Na⁺ and Ca²⁺into the cell when light is not hitting the cell. C) the entry of K⁺ into the cell when light is not hitting the cell. D) the exit of K⁺ out of the cell when light is not hitting the cell.

Question

Quizplus · Accepted Answer

In the dark, photoreceptors are depolarized due to the continuous influx of Na⁺ and Ca²⁺ ions through open cGMP-gated channels, creating a "dark current."

The "Dark Current" of Photoreceptors Refers to