The bones’ sizes ratio, their location and the difference between the surfaces size of the ear drum and the oval window, all influence the efficiency of the voice transmission to the inner ear.
This transmission has to overcome the amplification loss that is caused be moving from air-conducting (outer ear) to fluid-conducting (inner ear) since air and fluid got different resistance.
The oval window is one of two openings in the cochlea. The cochlea is filled with fluids, and shaped like a shell with 2.5 rounds.
The last of the three hearing bones functions as a piston and transmits the sound wave to the fluids in the cochlea. These movements vibrate different areas in the cochlea with different intensity. Low frequency sounds (and therefore, long wave length) will vibrate the top notch of the cochlea and high frequencies (and therefore, short wave length) will vibrate the part closer to the oval window.
Inside the cochlea, There is the Corti organ with lines of small hair cells. When a certain part of the cochlea vibrates, the hair cells in this part transform the movements to neural signals. These signals go through the hearing nerve that is connected to the hair cells, on the one hand, and to the brain on the other end.
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