An EMT (emergency medical technician) is attending to a man who has fainted. She shines a light in one of his eyes and observes that his pupil dilates. This is due to the fact that, when she shines the light in his eye, the:
A)pupil itself dilates.
B)iris surrounding the pupil opens.
C)lens behind the pupil closes.
D)cornea in front of the pupil dilates.

Question

Quizplus · Accepted Answer

When a light is shined into one eye, the pupil of that eye should constrict (not dilate) in response to the light. This is controlled by the iris, which surrounds and controls the size of the pupil. If the iris is functioning properly, it will open in response to low light (dilation) and close in response to bright light (constriction). Therefore, observing dilation of the pupil in response to a light suggests a dysfunction of the iris control and could indicate a neurological problem.

An EMT (Emergency Medical Technician) Is Attending to a Man