Your morning alarm includes a gradual increase in room lighting to help you awaken. This increase in ambient light triggers the _____ in your brain to constrict your pupils in response to the increase in light.
A) superior colliculi
B) periaqueductal gray
C) red nucleus
D) inferior colliculi

Question

Quizplus · Accepted Answer

The superior colliculi are responsible for controlling the dilation and constriction of the pupils in response to changes in ambient light. When there is an increase in light, the superior colliculi will signal the muscles in the iris to constrict the pupils to reduce the amount of light that enters the eye. Therefore, A) is the correct choice. The other options, (B) periaqueductal gray, (C) red nucleus, and (D) inferior colliculi, are not involved in the regulation of the pupils in response to changes in light.

Your Morning Alarm Includes a Gradual Increase in Room Lighting