Cochlear Hair Cells
Your basilar membrane is lined with tiny hair cells, which are responsible for converting mechanical vibration of the basilar membrane to a chemical signal that stimulates your auditory nerve.
Hair cells in your ear come in two flavours: one row of inner hair cells and three rows of outer hair cells. The inner hair cells are heavily connected to the auditory nerve, and they send sound information to your brain. The job of the outer hair cells, in contrast, is to amplify the sound vibrations by dancing along. Literally! (See for yourself in this little video here.)
Video credit Ashmore Lab