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Hearing and EquilibriumHearing and Equilibrium
Outer EarOuter Ear Auricle– “ear” shell-Auricle– “ear” shell-
shaped, surrounds shaped, surrounds external opening to external opening to auditory canalauditory canal
Auditory canal – Auditory canal – channel through channel through temporal bonetemporal bone
Tympanic Tympanic membrane-membrane-eardrum; vibrates eardrum; vibrates when stimulated by when stimulated by sound waves.sound waves.
Middle EarMiddle Ear
Air filled cavity called Air filled cavity called tympanic cavity tympanic cavity (middle ear cavity)(middle ear cavity)
From eardrum to From eardrum to bony wall with oval bony wall with oval and round windowand round window
Auditory tube runs Auditory tube runs down connecting ear down connecting ear to throatto throat
Functional parts of middle Functional parts of middle earear Ossicles- 3 small bonesOssicles- 3 small bones
Hammer (malleus), Anvil Hammer (malleus), Anvil (incus), and Stirrup (incus), and Stirrup (stapes)(stapes)
Eardrum vibrates hammer, Eardrum vibrates hammer, which moves anvil, which which moves anvil, which then moves stirrup, then moves stirrup, opening oval window.opening oval window.
Oval window moves fluids Oval window moves fluids inside inner earinside inner ear
Inner EarInner Ear
Located deep Located deep inside temporal inside temporal bone (behind eye bone (behind eye socket)socket)
Contains 3 major Contains 3 major divisionsdivisions
Anatomy of Inner earAnatomy of Inner ear Cochlea- contains Cochlea- contains
auditory (cochlear) auditory (cochlear) nerve, which nerve, which transmits sound transmits sound impulses; hair cells impulses; hair cells receive vibrations receive vibrations from oval window, from oval window, indicating soundindicating sound
Different pitches Different pitches affect different areas affect different areas of cochleaof cochlea
Semicircular canalSemicircular canal
Located in inner earLocated in inner ear Responsible for Responsible for
maintaining maintaining balance/equilibriumbalance/equilibrium
Otoliths float inside Otoliths float inside canalcanal
Hair cells recognize Hair cells recognize when the otolith when the otolith moves, alerting the moves, alerting the body of its positioning body of its positioning when staticwhen static
Dynamic equilibriumDynamic equilibrium
Position while Position while moving is moving is determined in determined in semicircular canalsemicircular canal
Triggered when Triggered when spinning, moving spinning, moving on a boat, etc.on a boat, etc.
Causes dizziness Causes dizziness and motion sicknessand motion sickness
Types of DeafnessTypes of Deafness
Conduction – Conduction – problem in problem in conduction of sound conduction of sound vibrations; hearing vibrations; hearing aids can help by aids can help by transmitting sound transmitting sound to/through boneto/through bone
Sensorineural – Sensorineural – degeneration or degeneration or damage to nerves damage to nerves which carry which carry impulse.impulse.