The ear consists of three basic parts - the outer ear, the middle ear, and the inner ear. Each part of the ear has a specific role in the task of detecting and interpreting sound. The outer ear is called pinna. It collects and transmits the sound to the middle ear through the auditory canal.
At the end of the auditory canal there is a thin membrane called the eardrum or tympanic membrane. The eardrum moves inward and outward as the compression or rarefaction reaches it. In this way the eardrum vibrates. These vibrations are amplified by the three bones namely the hammer, anvil and stirrup in the middle ear.
The middle ear transmits these vibrations to the inner ear. Inside the inner ear, the vibrations or the pressure variations are converted into electrical signals by the cochlea. These electrical signals are sent to the brain via the auditory nerve and the brain interprets them as sound.