Outer hair cells in the cochlea have what role?

Outer hair cells in the cochlea have what role?

• A. They sense the initial mechanical vibration and convert it to neural signals.
• B. They are responsible for producing cerumen.
• C. They convert sound waves directly into neural impulses.
• D. They modulate the stiffness of the tectorial membrane, fine-tuning cochlear sensitivity.

Answer: (D)

Outer hair cells act as active amplifiers in the cochlea. When the basilar membrane moves in response to sound, these cells undergo electromotility—they change length in response to the receptor potential—which feeds energy back into the cochlear partition. This mechanical feedback changes the stiffness and motion of the organ of Corti and its contact with the tectorial membrane, boosting sensitivity to faint sounds and sharpening frequency selectivity. Hence, their role is to modulate the stiffness and motion of the tectorial membrane, fine-tuning cochlear sensitivity. The other options describe inner hair cell functions (transducing mechanical energy into neural signals) or non-auditory tasks like cerumen production.

Outer hair cells act as active amplifiers in the cochlea. When the basilar membrane moves in response to sound, these cells undergo electromotility—they change length in response to the receptor potential—which feeds energy back into the cochlear partition. This mechanical feedback changes the stiffness and motion of the organ of Corti and its contact with the tectorial membrane, boosting sensitivity to faint sounds and sharpening frequency selectivity. Hence, their role is to modulate the stiffness and motion of the tectorial membrane, fine-tuning cochlear sensitivity. The other options describe inner hair cell functions (transducing mechanical energy into neural signals) or non-auditory tasks like cerumen production.