Dilation of the Pupil is Mediated By

Question

Dilation of the pupil is mediated by
A) Parasympathetic output from the Edinger-Westphal nucleus
B) Sympathetic output from the superior celiac ganglion
C) Sympathetic output from the vagus nerve
D) Parasympathetic output from the vagus nerve
E) Sympathetic output from the inferior mesenteric ganglion

Accepted Answer

Dilation of the pupil, also known as mydriasis, is primarily mediated by the sympathetic nervous system. The superior cervical ganglion (not the superior celiac ganglion as mentioned in the options, which seems to be a mix-up), is responsible for the sympathetic innervation that causes the dilation of the pupil.