Which cranial nerve is responsible for the sense of smell?

• A. Optic nerve (CN II)
• B. Facial nerve (CN VII)
• C. Olfactory nerve (CN I)
• D. Trigeminal nerve (CN V)

Answer: (C)

The olfactory nerve, or cranial nerve I, is specifically dedicated to the sense of smell. It consists of sensory nerve fibers that transmit olfactory information from the receptors in the nasal mucosa to the olfactory bulbs in the brain. This direct pathway is essential for the perception of odors, making this nerve crucial for the sense of smell.

Other cranial nerves listed have different functions. The optic nerve is responsible for vision, carrying visual information from the retina to the brain. The facial nerve facilitates taste sensations from the anterior two-thirds of the tongue, as well as controlling the muscles of facial expression. Meanwhile, the trigeminal nerve is primarily involved in sensation from the face and motor functions such as biting and chewing. None of these nerves contribute directly to the sense of smell like the olfactory nerve does.