Anatomy and Physiology of Hearing Flashcards
external ear
includes auricle and external auditory canals
terminates at tympanic membrane
middle ear
air filled space within petrous portion of temporal bone
middle ear contains
malleus
incus
stapes
inner ear
houses sensory organs for hearing and balance
inner ear contains
semicircular canals
vestibule
cochlea
balance
semicircular canals
vestibule
hearing
cochlea
auricle/pinna
made of elastic cartilage
collects sound waves and sends to external auditory canal
external auditory canal
lined w/ hairs and ceruminous glands
tympanic membrane
separate external ear from middle ear
transfer sound waves to middle ear
3 auditory ossicles
malleus
incus
stapes
two muscles of middle ear
tensor tympani
stapedius
tensor tympani muscle
attached to malleus
innervated by trigeminal nerve
stapedius muscle
attached to stapes
innervated by facial nerve
function of 2 muscles
reflexively dampen excessively loud sounds
auditory tubes
opens in pharynx and equalizes pressure between outside air and middle ear cavity
bony labyrinth
tunnels and chambers inside temporal bone
endosteum
layer of connective tissue that lines the internal surface of the bony labyrinth
membranous labyrinth
inside bony labyrinth
smaller set of membranous tunnels and chambers
3 regions of bony labyrinth
vestibule
semicircular canals
cochlea
3 regions of membranous labyrinth
scala vestibuli
scala media
scala tympani
scala vestibuli
extends from oval window to helicotrema
perilymph
scala media
between Scala vestibule and Scala tympani
endolymph
scala tympani
extends from helicotrema to round window
perilymph
vestibular membrane
wall between Scala vestibule and Scala media
basilar membrane
wall between Scala media and Scala tympani
spiral of organ/organ of corti
houses sensory cells for hearing
hair cells
sensory cells for hearing
have synapses w/ sensory neurons that join to form cochlear nerve
cochlear nerves
joins vestibular nerve to form vestibulocochlear nerve
speed of sound
332 m/s
amplified vibrations in perilymph
more force is required to cause vibration in a liquid
mechanical force of vibration
amplified about 20-fold passing from tympanic membrane
sound attenuation reflex
muscles reflexively dampen excessively loud noises to protect delicate ear structures
Sound attenuation reflex responds most to?
low frequency sounds
facial nerve and stapedius muscle
primarily involved in sound attenuation reflex
trigeminal nerve and tensor tympani
stimulated by extremely loud noise
higher pitched tones
optimal vibrations near base of cochlea
lower pitched tones
optimal vibrations near apex of cochlea