A Sudden Increase of Light into the Eye Would Cause

Question

A sudden increase of light into the eye would cause
A) contraction of the sphincter pupillary muscles.
B) contraction of the radial pupillary muscles.
C) conversion of 11-trans to 11-cis retinal.
D) an increase in the size of the pupil.
E) parasympathetic stimulation to the pupil.

Accepted Answer

A sudden increase of light into the eye would stimulate the photoreceptor cells and send signals to the brain via the optic nerve. This would activate the parasympathetic nervous system, which would cause the sphincter pupillary muscles to contract and reduce the size of the pupil to restrict the entrance of light into the eye.