Inner Ear • Overview • Cochlea • Organ of Corti • Hair Cells • Basilar Membrane
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.
Cochlear Fluids • Perilymph - scala vestibuli and scala tympani • Endolymph - scala media • Cortilymph - tunnel of corti in tunnel of corti
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.
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.
Cochlea Cross-Section Scala vestibuli Scala media Scala tympani
Summary • You know the drill.