Which cranial nerve is responsible for the sense of smell?

• A. Trigeminal nerve
• B. Optic nerve
• C. Olfactory nerve
• D. Facial nerve

Answer: (C)

Smell is carried by a dedicated sensory nerve that starts in the nasal mucosa and transmits olfactory information to the brain. This is the olfactory nerve, which is the first cranial nerve. Its fibers pass through the cribriform plate to the olfactory bulb and then project to the primary olfactory cortex, with strong connections to limbic areas, allowing odor perception and related memories and emotions. The other nerves listed have different primary roles: the trigeminal nerve provides facial sensation and some irritant sensing in the nose but not odor perception; the optic nerve handles vision; and the facial nerve controls facial movements and some taste. Hence, sense of smell is mediated by the olfactory nerve.