Which structure converts sound waves into neural signals?

Which structure converts sound waves into neural signals?

• A. Cochlea
• B. Tympanic membrane
• C. Ossicles
• D. External auditory canal

Answer: (A)

Sound waves are converted into neural signals in the cochlea, the spiral-shaped structure in the inner ear. When the eardrum and middle-ear bones transfer vibrations into the cochlear fluid, the basilar membrane inside the cochlea vibrates in a frequency-dependent way. Hair cells along this membrane have bundles of stereocilia that bend as the membrane moves. This bending opens ion channels, creating receptor potentials and causing the hair cells to release neurotransmitters onto auditory nerve fibers. Those signals then travel to the brain, encoding the pitch and loudness of sounds. The other structures play different roles: the tympanic membrane (eardrum) simply converts sound waves into mechanical vibrations, the ossicles (tiny bones) amplify and pass those vibrations to the inner ear, and the external auditory canal channels sound toward the eardrum. But the actual conversion from mechanical energy to neural signals happens in the cochlea.

Sound waves are converted into neural signals in the cochlea, the spiral-shaped structure in the inner ear. When the eardrum and middle-ear bones transfer vibrations into the cochlear fluid, the basilar membrane inside the cochlea vibrates in a frequency-dependent way. Hair cells along this membrane have bundles of stereocilia that bend as the membrane moves. This bending opens ion channels, creating receptor potentials and causing the hair cells to release neurotransmitters onto auditory nerve fibers. Those signals then travel to the brain, encoding the pitch and loudness of sounds.

The other structures play different roles: the tympanic membrane (eardrum) simply converts sound waves into mechanical vibrations, the ossicles (tiny bones) amplify and pass those vibrations to the inner ear, and the external auditory canal channels sound toward the eardrum. But the actual conversion from mechanical energy to neural signals happens in the cochlea.