200057.vtt
1.69 KB
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WEBVTT
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Sound waves entering the ear travel through the external auditory canal
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before striking the eardrum and causing it to vibrate.
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The eardrum is connected to the malleus, one of three small bones of the middle ear.
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Also called the hammer, it transmits sound vibrations to the incus,
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which passes them to the stapes.
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The stapes pushes in and out against the structure called the oval window.
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This action is passed onto the cochlea, a fluid-filled snail-like structure that
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contains the organ of Corti, the organ for hearing.
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It consists of tiny hair cells that line the cochlea.
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These cells translate vibrations into electrical impulses
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that are carried to the brain by sensory nerves.
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In this cut-view, you can see the organ of Corti with its four rows of hair cells.
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There is an inner row on the left and three outer rows on the right.
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Let's watch this process in action.
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First, the stapes rocks against the oval window. This transmits waves of sound through the
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cochlear fluid, sending the organ of Corti into motion.
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Fibers near the upper end of the cochlea resonate to lower frequency sound.
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Those near the oval window respond to higher frequencies.