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The Inner Ear - Coggle Diagram

- - - - the scala vestibuli, the scala media, and the scala tympani (MTV :tv:)
        
        membranes that separate these chambers
        
        Reissner’s membrane :car:
        
        separates the scala vestibuli from the scala media
        
        basilar membrane :silhouette:
        
        separates the scala tympani from the scala media
        
        Sitting upon the basilar membrane is the organ of Corti
        
        contains auditory receptor cells :woman-getting-haircut:
        
        hanging over this organ is...
        
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        convert mechanical energy into a change in membrane polarization
        
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        called hair cells because each one has 10–300 hairy-looking stereocilia on top
        
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        At the apex of the cochlea, the scala media is closed off
        
        the scala tympani becomes continuous with the scala vestibuli at a hole in the membranes called the helicotrema 🐚
        
        fluid in the scala vestibuli and scala tympani, called perilymph (similar to CSF - low K, high Na)
        
        The scala media is filled with endolymph (concentrations similar to intracellular fluid – high K, low Na)
        
        difference in ion content is generated by active trans- port processes taking place at the stria vascularis Ⓜ️
        
        absorbs sodium from, and secretes potassium into, the endolymph.
        
        Because of the ionic concentration differences and the permeability of Reissner’s membrane, the endolymph has an electrical potential that is about 80 mV more positive than that of the perilymph
        
        this is called the endocochlear potential
        
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  - - - structures inside the cochlea are not rigid
        
        basilar membrane is flexible and bends in response to sound.
        
        two structural properties that determine the way it responds to sound
        
        the membrane is wider at the apex than at the base by a factor of about 5
        
        the stiffness of the membrane decreases from base to apex, the base being about 100x stiffer :swimmer:
        
        Sound causes a continual push–pull motion of the footplate
        
        movement of the perilymph and endolymph makes the basilar membrane bend near its base
        
        starting a wave that propagates toward the apex. :ocean:🪢
        
        The distance the wave travels up the basilar membrane depends on the frequency of the sound.
        
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