Pinna
part of outer ear
funnel of cartilage
helps to collect sound vibrations
directs sound waves into external auditory canal
Auditory Canal
sound waves are funneled into the canal and amplified, natural acidity helps to protect against infections
outer ear
pinna, auditory canal
inner ear
oval window, round window, cochlea, and semicircular canals
middle ear
tympanic membrane/ear drum, eustachian tube, auditory ossicles(MALLEUS, INCUS, STAPES)
auditory canal
sounds waves and funneled and amplified, natural acidity helps to protect it from infection
tympanic membrane
sound waves from auditory canal hit the membrane and causes it to vibrate, reproduces frequency and form of sound wave
what is the oval window?
it is the membrane that connects the middle ear to the upper half of the cochlea
oval window
vibrations from the isosceles are transferred to the cochlea via the action of the stapedial footplate in the oval window
what is the round window?
membrane the connects the middle ear to the lower half of the cochlea
round window
aids fluid motion within the cochlea and serves to equalize the hydraulic pressure
Eustachian tube
equalizes air pressure inside and outside of the tympanic membrane and allows the drainage of normal and diseased secretions of the middle ear
cochlea
converts stimulus from outside environment into nerve impulses for transmission to the brain
the more hair cells that vibrate, the
louder the sound
the longer hairs found near top of the cochlea pick up
low frequencies
hairs near middle of spiral response are moved by
middle frequencies
shorter, thinner hairs at the base of the cochlea respond to
higher frequencies
semicircular canals
hair cells within canals perceive sense of balance and space, fluid flows in certain directions when you move your head, different movements affect different canals, aids in maintaining balance
how does hearing work?
Sound waves enter the ear canal and make the ear drum vibrate. This action moves the tiny chain of bones (ossicles - malleus, incus, stapes) in the middle ear. The last bone in this chain 'knocks' on the membrane window of the cochlea and makes the fluid
Presbycusis
-usually happens as people age, and people usually have difficulty hearing high pitched noises
-causes: changes in the inner ear of a person as they age, but this can also result from a change in the middle ear or from complex changes along the nerve path
Mieniere's Disease
-disorder in the inner ear that causes episodes in which you feel as if you're spinning, and you have fluctuating hearing loss. You may also experience tinnitus
-causes: abnormal amount of fluid in the inner ear, head trauma
-symptoms: episodes of vertigo
hearing loss from bacterial meningitis
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