Which part of the auditory system is responsible for picking up frequency and intensity?

The cilia, which are tiny hair-like structures located on the hair cells within the cochlea, play a crucial role in detecting sound frequencies and intensities. When sound waves enter the cochlea, they cause the fluid inside it to move, which in turn causes the cilia to bend. This mechanical movement of the cilia is converted into electrical signals that the auditory nerve sends to the brain for processing.

The response of the cilia to different frequencies allows the auditory system to distinguish pitch, while the degree of bending indicates intensity or loudness. This precise mechanism is essential for our ability to perceive a wide range of sounds in our environment, making cilia integral to auditory processing.

Comparatively, the cochlea itself houses the cilia and is responsible for overall sound processing, but the specific task of frequency and intensity detection is performed by the cilia. The auditory cortex, while critical for interpreting these signals once they reach the brain, does not physically sense sound frequencies or intensities. The Eustachian tube serves a different function related to equalizing pressure in the ear, rather than sound detection.