Inner Ear

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Inner Ear

• Overview
• Cochlea
• Organ of Corti
• Hair Cells
• Basilar Membrane

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Inner Ear
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Inner Ear
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Membranous Labrynth
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(No Transcript)
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Cochlea

• Spiral - turban shaped
• In humans
• Two and a half turns
• 35 mm long
• 5 mm high
• 9 mm diameter at base but becomes narrower at
  apical end.

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Cochlea
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Cochlea
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Cochlea (cochlear branch of the VIII nerve)
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Cochlea (spiral ganglion)
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Cochlea (modiolus)
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Cochlea (modiolus)
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Cochlea (scala vestibuli)
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Cochlea (scala media)
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Cochlea (scala tympani)
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Cochlear Fluids

• Perilymph - scala vestibuli and scala tympani
• Endolymph - scala media
• Cortilymph - tunnel of corti in tunnel of corti

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Cochlear Fluids

• Function
• Deliver nutrients and removes waste from inner
  ear cells.
• Important for transduction process between
  hydraulic and neural-electric energy.
• Acts as a medium to transfer hydraulic vibratory
  motion that causes hair cell distortion.

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Cochlear Fluids

• Perilymph
• Similar to cerbrospinal fluid
• Very high in Sodium (Na)
• Very low in Potasium (K)
• Overall has a negative ionic charge
• Endolymph
• Very low in Na
• Very high in K
• Overall has a positive ionic charge
• Cortilymph
• Similar to perilymph in chemical composition and
  ionic charge.
• Possibly increases electrical charge in hair
  cells.

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Cochlea Cross-Section
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Cochlea Cross-Section
Scala vestibuli
Scala media
Scala tympani
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Cochlea Cross-Section (scala vestibuli)
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Cochlea Cross-Section (scala media)
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Cochlea Cross-Section (scala tympani)
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Cochlea Cross-Section(organ of corti)
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Cochlea Cross-Section (Reissners membrane)
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Cochlea Cross-Section (basilar membrane)
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Cochlea Cross-Section
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Cochlea Cross-Section (spiral ligament)
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Cochlea Cross-Section(spiral lamina)
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Cochlea Cross-Section
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Cochlea Cross-Section
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Summary

• You know the drill.