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3 regions
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outer
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middle
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inner
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Sound waves
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collected by pinna are directed to eardrum
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causes eardrum to vibrate
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Earbones
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amplify and transmit vibration to oval window
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Oval window
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vibrates
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cause perilymph in cochlea to vibrate
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vibrations in perilymph is transmitted to endolymph of cochlea
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Sensory hair cells (central canal)
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stimulated
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generate nerve impulses
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produce sensation of hearing
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nerve impulses travel along auditory nerves to auditory centre in brain
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vibration in perilymph transmitted to round window
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Round window
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releases fluid pressure in the cochlea to the air in middle ear
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Pinna (ear flap)
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flap of cartilage covered by skin
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collects sound waves in surrounding
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directs them along auditory canal to eardrum
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Auditory canal
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produces wax
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wax
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lubricates canal
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traps dirt and bacteria to prevent them entering the middle ear
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Eardrum
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thin, elastic membrane at the end of auditory canal
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convert sound waves to vibrations
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Ear bones
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3 tiny ear bones
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smallest bones in body
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amplify and transmits vibration from eardrum to oval window
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Oval window
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flexible membrane
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transmits vibration from ear bones to inner ear
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Round window
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releases fluid pressure in cochlea into the air
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Eustachian tube
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tube connecting middle ear to pharynx
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normally closed
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swallowing to open it to allow air to enter or leave middle ear
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equalised the pressure on either side of eardrum
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Unequal pressure
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eardrum will bulge
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bulging eardrum cannot vibrate freely
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cannot hear clearly
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Cochlea
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for hearing
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coiled tube with three parallel canals separated by membranes
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perilymph
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fluid in upper and lower canal
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endolymph
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fluid in central canal
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sensory hair cells
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in central canal
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detects vibrations of endolymph
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endolymph vibrates
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sensory hair cell hairs are bent
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sensory hair cells generate nerve impulses
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nerve impulses travels along auditory nerves to auditory centre in brain
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Semicircular canals
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not involved in hearing
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sensory hair cells
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detection of head movements
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stimulated, send nerve impulse to brain
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brain coordinate muscled to maintain body balance
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Cheatography n. The art of mapping complex subjects into clear, instantly navigable reference guides.
