AEMCA Practice Exam

What is the role of cranial nerve 3?

1. Controls pupil dilation and constriction

2. Involved in hearing

3. Transmits taste sensations

4. Controls emotional responses

The correct answer is: Controls pupil dilation and constriction

Cranial nerve 3, also known as the oculomotor nerve, primarily controls pupil dilation and constriction, as well as most eye movements. It plays a crucial role in regulating the size of the pupil in response to light and accommodation for near vision. The nerve innervates several muscles, including the sphincter pupillae, which is responsible for constricting the pupil, and the dilator pupillae, indirectly controlled by other pathways. This autonomic function is essential for protecting the retina from excessive light and aiding in visual clarity during different distances. While other cranial nerves are responsible for functions like hearing, taste, or emotional responses, cranial nerve 3 is specifically focused on controlling the pupil and coordinating movements of the eye, making the choice related to pupil dilation and constriction the correct one.