Final answer:
The cochlear branch of the vestibulocochlear cranial nerve forms from the axons of hair cells in the spiral organ, where mechanoreceptor stereocilia convert sound vibrations into nerve impulses that travel to the brain for sound processing.
Step-by-step explanation:
The axons from the hair cells of the spiral organ form the vestibulocochlear cranial nerve, specifically the cochlear branch, which is responsible for transmitting auditory information to the brain. These hair cells are contained within the organ of Corti, and function as mechanoreceptors. They have hair-like stereocilia that, when moved by sound-wave-induced vibrations, bend and cause the hair cells to depolarize. This depolarization triggers nerve impulses that travel along the auditory nerve fibers, leading to the auditory cortex for sound perception.
The spiral ganglion is a key structure here as it contains the cell bodies of the auditory nerve fibers that transmit these signals. A precise understanding of sound involves not only the transduction of sound waves by the hair cells but also the involvement of the spiral ganglion and its location with respect to the neuronal cell bodies that carry the auditory information along the eighth cranial nerve.