APEA Neurology Practice Test 2026 – Comprehensive Exam Prep

The sense of smell is carried by the first cranial nerve, the olfactory nerve. Odor molecules activate receptors in the nasal mucosa, and the axons of these olfactory neurons bundle together to form the olfactory nerve as they pass through the cribriform plate into the olfactory bulb. From there, the signal goes to higher smell-related brain regions such as the piriform cortex and entorhinal cortex (with connections to amygdala), giving us odor perception. This nerve is purely sensory and is distinct from the others listed: the second nerve handles vision, the third nerve controls most eye movements and pupil constriction, and the eighth nerve handles hearing and balance.