Question

Explain the mechanisms that unfold that allow you to discriminate between high pitched and low pitched sounds. Be sure to discuss and describe the structures involved in this process.

Answer 1

The sound are waves produced by vibrations. The loudness of a sound depends upon the amplitude of the vibrating particles, while the pitch of the sound depends upon the frequency of the vibrating particles.

When a sound wave ( vibrating air particles as per the vibration of vibrating particles) reaches the ear, it results in the vibration of the eardrum as per the vibration produced by the vibrating particles. The vibration of the ear drum, vibrates the ossicles (3 in number) of the middle ear which inturns vibrate the basilar membrane present in the cochlea. The nerves (auditory nerves) attached to this basilar membrane sends signals to the brain and we can hear the sound accordingly.

The cochlea have basilar membrane for high frequency sounds at its apex or near, while the cochlea has basilar membrane at the base or far end for low frequency sounds. The high frequency waves are high pitched sound, while the low frequency sounds are low pitched sound. Also the basilar membrane at cochlea for high pitched sound (at near or apex) are narrow and stiff, while for the low pitched sound are wide and loose.

So, as per the frequency of the sound reaches the cochlea, the specific part of the basilar membrane of the cochlea vibrates accordingly. So that the nerves attached to that part of the basilar membrane only carries signal to the brain and we can hear sound with the same pitch similar to the time of production.

The high pitch sound vibrates the basilar membrane at the near end, while the low pitch sound vibrates the far end membrane of the cochlea. As high pitch sounds have high frequency while the low pitch sounds have low frequency.