Question

Threshal -1 time ) Describe your perception of a pressure wave that initially stimulates many organs of corti, at about 30mm from the oval window, then steadily decreases the total number of organs it stimulates as it crosses the basilar membrane closer and closer to the oval window. 4

Answer 1

The inner ear has 2 separate regions - cochlea and vestibule. These are responsible for hearing and balance. The neural signals from these two organs are relayed to the brain stem through separate fiber bundle.sound is transduced into neural signals within the cochlea which contains sensory neurons of spiral ganglia. The cochlea is attached to the stapes through the oval window.

Cochlear duct consists of scala vestibule and scala tympani which run along the side of the cochlear duct. The cochlear duct contains several organs of Corti. This is responsible for the transduction of waves into neural signals. The organs of Corti lie upon the basiliar membrane. As the fluid motion, the basilar membrane moves at a specific spot depending n the frequency of the waves. Higher frequency waves move the region of the basilar membrane that is close to the base of the cochlea and lower frequency away. Thus the wave velocity decreases from the base of the cochlea to tip. Movement of basilar membrane induces forces in the stereocilia of the hair cells and triggers the series of mechanical, biochemical and electrical events that are responsible for mechanical sensory transduction and initial signal processing. This decrease in the frequency of waves explains the reason why pressure wave decreases the total no. of organs as it crosses the basilar membrane closer to the oval window.

Urticle Semicircular canals Oval window Saccule Cochlea Basilar membrane and hair cells