Explain the Functions of Inner Ear
The inner ear plays an important function in the detection of sound. In the last section, we left middle ear function at the point where the sound stimulus results in movement of the stapes. The footplate of the stapes is adjacent to the oval window of the inner ear as you learnt above. The stapes footplate moves in and out like a piston in response to sound stimuli. Since the footplate is adjacent to the oval window of the inner ear, its 'movements produce pressure variations in cochlear fluids.
These variations result in movement of the basilar membrane (BM) found in the inner ear. Movements of the BM result in movements of hair cells. Hair cell movement displaces their steriocillia, which in turn, enhances or depresses hair cell excitability. Afferent nerve fibers to the centre nervous system convey altered excitability of hair cells. In short, the inner ear transducts vibratory stimulus to electrical signals to be transmitted to the central nervous system. But the inner ear is more than a transducer. It also performs a preliminary analysis of the sound stimulus in terms of its frequency and amplitude characteristics. The BM plays an important role in this analysis. With over a million essential moving parts, the auditory receptor organ or cochlea is the most complex mechanical apparatus in the human body. Surely you would agree, having looked at the structure and the physiological role of this organ now.