Which cranial nerve is associated with smell?

The cranial nerve associated with smell is the olfactory nerve, which is designated as cranial nerve I. This nerve is responsible for transmitting sensory information related to olfaction, allowing individuals to perceive odors. The olfactory nerve originates from the olfactory bulb and extends into the nasal cavity, where it detects chemical stimuli (odor molecules) present in the air.

Upon stimulation by these odor molecules, the olfactory receptors send signals through the olfactory nerve to the brain, where the perception of smell is processed. This function is distinct and separate from the roles of the other cranial nerves listed. For instance, the optic nerve, while crucial for vision, does not have a role in the sense of smell. Similarly, the oculomotor nerve is primarily involved in eye movement and pupil size, while the trigeminal nerve is related to facial sensations and motor functions such as biting and chewing, but not to olfactory perception. Therefore, cranial nerve I is uniquely responsible for the sense of smell.