Question

Give account on mechanism of hearing.

Answer 1

The pinna of the external region collects the sound waves and directs it towards ear drum or external auditory canal. These waves strike the tympanic membrane and vibrations are created. Then, these vibrations are transmitted to the oval window, fenestra ovalis, through three ear ossicles, named as malleus, incus, and stapes. These ear ossicles act as a lever and transmit the sound waves to internal ear. These vibrations from fenestra ovalis are transmitted into the cochlear fluid. This generates sound waves in the lymph. The formation of waves generates a ripple in the basilar membrane. This movement bends the sensory hair cells present on the organ of Corti against tectorial membrane. As a result of this, sound waves are converted into nerve impulses. These impulses are then carried to the auditory cortex of brain via auditory nerves. In cerebral cortex of the brain, the impulses are analysed and the sound is recognized.