Lecture Wednesday September 19: histology of the ear

Basic Ear Anatomy



- Relationship of middle ear ossicles to the inner ear
Sound waves vibrate the tympanic membrane > vibrates the oval window > fluid wave through the cochlea > wave exits (dampened) at the round window



Histology of the Cochlea
Components:
A. 3 ducts: scala vestibuli, scala tympani, and cochlear duct
B. 3 membranes: vestibular, basilar and tectorial
C. Hair cells in the organ of corti
D. Spiral ganglion (CN VIII)


Displacement of perilymph in the scala vestibuli will bend the vestibular membrane > displaces the endolymph in the cochlear duct > bends the basilar membrane.
Movement of the basilar membrane to which the hair cells are attached cause bending of the hair cell processes embedded in the tectorial membrane > depolarization of the hair cells > depolarization of CN VIII at spiral ganglion.


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