Final answer:
The basilar membrane vibrates creating movement against the tectorial membrane, bending hair cells, and leading to neural impulses via the cochlear nerve.
Step-by-step explanation:
As sound waves vibrate the basilar membrane, hair cells are pushed up against the tectorial membrane, causing their hairs to bend. This bending action stimulates the inner hair cells, resulting in the release of an excitatory neurotransmitter at a synapse with a sensory neuron. The sensory neuron then conducts action potentials to the central nervous system through fibers of the cochlear nerve. The pressure bends the membrane of the cochlear duct at a point of maximum vibration for a given frequency, causing hair cells in the basilar membrane to vibrate. There is some modulation or 'sharpening' that occurs, allowing the brain to fine-tune the response of hair cells to certain frequencies.