Which cranial nerve is primarily responsible for hearing?

The Vestibulocochlear nerve, also known as cranial nerve VIII, is primarily responsible for hearing and balance. It is composed of two parts: the cochlear nerve, which transmits auditory information from the cochlea of the inner ear to the brain, and the vestibular nerve, which helps with balance by carrying information about the position and movement of the head.

This nerve plays a crucial role in the auditory system as it allows us to detect sound vibrations and interpret them. Damage or dysfunction of the vestibulocochlear nerve can result in hearing loss or balance disorders, further underscoring its importance in auditory and vestibular function.

Regarding the other cranial nerves mentioned: the vagus nerve is involved in various autonomic functions including heart rate and digestion; the facial nerve is responsible for facial movements and sensations; and the optic nerve is critical for vision. None of these nerves are responsible for transmitting auditory information, making the vestibulocochlear nerve the clear choice for hearing.