Which cranial nerve controls the sense of smell?

The olfactory nerve is responsible for the sense of smell, making it the correct answer. This nerve is the first cranial nerve and is primarily involved in the detection of odorants in the environment. It consists of sensory fibers that originate from the olfactory epithelium in the nasal cavity and transmit information about smell to the olfactory bulb in the brain.

The olfactory nerve plays a unique role among cranial nerves as it is directly connected to the limbic system, which is involved in emotion and memory, thereby linking smell to these functions. This connection explains why certain smells can evoke strong memories or emotional responses.

In contrast, the facial nerve has diverse functions, including the control of facial expressions and the sense of taste from the anterior two-thirds of the tongue. The optic nerve is responsible for vision, transmitting visual information from the retina to the brain. The vestibulocochlear nerve is involved in hearing and balance, not smell. Each of these other cranial nerves has distinctly different roles that do not relate to olfactory processing.