Photoreceptors
A) are hyperpolarized in the dark and depolarized by light.
B) are depolarized in the dark and hyperpolarized by light.
C) produce action potentials in response to being in the dark.
D) experience no refractory periods in response to light.

Question

Quizplus · Accepted Answer

Photoreceptors, such as rods and cones, are depolarized in the dark, meaning that they constantly release neurotransmitters. However, when light strikes these cells, this depolarization stops, hence the cells become hyperpolarized. This change in electrical signaling leads to a chain reaction that eventually leads to the generation of action potentials in the optic nerve. Therefore, option B is the correct answer. Option A is incorrect since photoreceptors are not hyperpolarized by light, but rather they are inhibited. Option C is incorrect since photoreceptors do not produce action potentials; instead, they release neurotransmitters that trigger action potentials in downstream cells. Option D is incorrect since photoreceptors, like most neurons, undergo refractory periods after experiencing action potentials, even in response to light.