Auditory Structure Part 2 PDF

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Sundwora b hig as + oushedova window 41014/09 Grand Cause han then since in , Fig and 01fgets by gotheStapes Sirclar elidmoucochleaallthe window back to J composed toEas +tip, over the of or window g , fluid ois pushed cares out Starvibrant vibra on - up per membrane bes opthair 3 # Auditory Structure – Part 2 nocilium Whatthe S • • • ↓ as Membrane gets pushed up& down these hair Cells more back sells & lower * membrane Y PS I Focus on cochlea and inner ear & forth Let’s unroll the cochlea. Stapes – moving back and forth at same frequency as stimulus. It pushes the elliptical window back and forth. o There’s fluid inside the cochlea, which gets pushed around cochlea, and comes back around. Organ of Corti splits cochlea into 2 – the upper and lower membrane. Cross section of Organ of Corti o Upper and lower membranes, and little hair cells. As fluid flows around the organ, it causes hair cells to move back and forth. o At the upper membrane: The hair cells/cilia are called the hair bundle and it is made of little filaments. Each filament is called a kinocilium. Tip of each kinocilium is connected by a tip link which is attached to gate of K+ channel. When the tip links get pushed back and forth by endolymph movement, they stretch and allows K+ to flow inside the cell from the endolymph (which is K+ rich) o Ca2+ cells get activated when K+ is inside, so Ca2+ also flows into the cell, and causes an AP, which then activates a spiral ganglion cell, which then activates the auditory nerve. 29 flow down mem flow fluid - a um has upper membrane