When the doctor shines a penlight into the patient's eye, which of the following occurs?
A) The parasympathetic nervous system is activated, which causes contraction of the outer radial muscle of the iris and pupillary dilation.
B) The sympathetic nervous system is activated, which causes contraction of the outer radial muscle of the iris and pupillary constriction.
C) The parasympathetic nervous system is activated, which causes contraction of the inner circular muscle of the iris and pupillary constriction.
D) The parasympathetic nervous system is activated, which causes contraction of the outer radial muscle of the iris and pupillary constriction.
E) The sympathetic nervous system is activated, which causes contraction of the outer radial muscle of the iris and pupillary dilation.

Question

Quizplus · Accepted Answer

The parasympathetic nervous system is responsible for the pupillary light reflex, which involves the contraction of the inner circular muscle of the iris, leading to pupillary constriction in response to light.

When the Doctor Shines a Penlight into the Patient's Eye