Detection of sound vibrations: hair cells arranged in rows of inner hair cells (responsible
for hearing) and outer hair cells (regulate tension on basilar membrane)
• Tip link (gating spring): attaches tip of each stereocilium in hair bundle to side of
longer stereocilium; as stereocilia bend, they open K+ gates (mechanically gated
ion channel)
Bending steriocilia in one direction
depolarizes the cell and stimulates
neurotransmitter release.
Bending in the opposite direction
repolarizes the cell and stops the release.
• Basilar membrane is narrow and stiff (HIGH PITCH) near oval window, wider at
outer end of cochlear duct (LOW PITCH); Hair cells in organ of Corti "tuned" to
certain sound frequencies by way of location in cochlea due to degree of stiffness
in membrane
for hearing) and outer hair cells (regulate tension on basilar membrane)
• Tip link (gating spring): attaches tip of each stereocilium in hair bundle to side of
longer stereocilium; as stereocilia bend, they open K+ gates (mechanically gated
ion channel)
Bending steriocilia in one direction
depolarizes the cell and stimulates
neurotransmitter release.
Bending in the opposite direction
repolarizes the cell and stops the release.
• Basilar membrane is narrow and stiff (HIGH PITCH) near oval window, wider at
outer end of cochlear duct (LOW PITCH); Hair cells in organ of Corti "tuned" to
certain sound frequencies by way of location in cochlea due to degree of stiffness
in membrane
