What is the primary function of the Olfactory nerve?

The primary function of the Olfactory nerve is sensory function for smell. This cranial nerve, specifically known as the first cranial nerve (CN I), is primarily responsible for the sense of olfaction. It transmits sensory information from the olfactory epithelium in the nasal cavity to the olfactory bulb in the brain, where the sensation of smell is processed.

The role of the Olfactory nerve is crucial for detecting and identifying different odors, which can influence taste and evoke memories. While the sense of taste is related to gustatory function, it primarily involves different cranial nerves, particularly the facial nerve (CN VII) and the glossopharyngeal nerve (CN IX). The other options relate to motor functions for facial expression and innervation of extraocular muscles, which involve different cranial nerves such as the facial nerve (for facial expressions) and oculomotor nerve (for movement of the eyes). Thus, the correct answer emphasizes the sensory role of the Olfactory nerve specifically linked to the sense of smell.