The Ear Flashcards
what is the basic anatomy of the ear?
pinna
external ear canal
tympanic membrane
middle ear
inner ear
what are the functions of the external ear?
collect sound waves
conduct sound waves to tympanic membrane
determine origin of sound waves
what is the cartilage of the ear that expands to form pinna and is funnel shaped?
auricular
what is the cartilage of the ear that fits w/in the auricular, overlaps the osseous external auditory meatus, and is for flexibility?
annular
what are the components of the external ear canal?
helix (rostra)
tragus (lateral)
antitragus (caudal)
intertragic incisure
what is the name of the division between the vertical and horizontal canal?
noxon’s ridge
what are bacteria which are normal microflora in the outer ear?
staphylococci
micrococcus spp.
beta-streptococcus
corynebacterium spp.
what is the name of yeast normally found in outer ears?
malassezia pachydermatis
which ear gland is superficial and the dutcs open into the hair follicle?
sebaceous
which ear gland is simple & coiled, located deep to the sebacious glands, are modified apocrine glands, and ducts open into the hair follicle or surface of the ear?
ceruminous
what is the emulsion along the ear canal which is removed by epithelial migration, and is the secretions of desquamated keratinize epithelial cells?
cerumen
what are the components of the middle ear?
tympanic membrane
auditory ossicles
typanic cavity
eustachian (auditory) tube
what are the three parts of the tympanic membrane?
pars flaccida
pars tensa
stria mallearis
a bulging pars flaccida is not an indication of otitis media except for in ___ ?
Charles king cocker spaniel dogs
what are the three auditory ossicles?
malleus
incus
stapes
where does the stapes base attach to?
round window
what is the muscle that inserts on the malleus?
tensor tympani m.
what is the muscle that inserts on the stapes?
stapedius m.
what are the three parts of the tympanic cavity?
epitympanic recess
ventral tympanic cavity
tympanic cavity proper
what are the three windows in the tympanic cavity?
round window
oval window
auditory tube
cats have complete while dogs have an incomplete ___?
bulla septum
what is the name of the ridge separating the bulla septum in the dog?
rosychuk’s ridge
where is the inner ear housed?
bony labyrinth
where is the bony labyrinth housed?
membranous labyrinth
the cochlea is housed within the ___ ___ bone
petrous temporal
what is the superior duct of the cochlea?
scala vestibuli
what is the medial duct of the cochlea?
scala media
what is the inferior duct of the cochlea?
scala tympani
what is the name of the membrane which is the floor of the scala vestibule and the roof of the scala media?
ressner’s membrane
what is the name of the membrane which is the floor of the scala media and the roof of the scala tympani?
basilar membrane
what are the two fluids of the scalae of the cochlea?
perilymph
endolymph
where is perilymph found in in the cochlea?
scala vestiboli
scala tympani
where is endolymph found in the cochlea?
scala media
what is the outer wall of the cochlea?
spiral ligament
what composes the stria vascularis of the cochlea?
blood vessels
endolymph
what are the components of the organ of corti?
tectorial membrane
reticular lamina
hair cells (inner & outer)
supporting cells
basilar membrane
which hair cell is the actual receptor for hearing?
inner hair cell
whihc hair cell adjusts the tuning and sensitivity of the inner hair cell?
outer hair cell
which hair cell is most susceptible to damage?
outer hair cell
what is the dorsal component of the hair cell that sticks out past the cell?
stereocilia
what is the name for the tallest stereocilia?
kinocilium
what are the steps for sound to be “heard”?
mechanical input from stapes to oval window
expansion of round window
compression wave - stapes in, round window out, basilar membrane down
rarefaction wave - round window in, basilar membrane up, stapes out, depolarize
vibratory inputn set up traveling wave
what is determined by the rate of action potentials firing?
intensity
what is determined by the portion of the organ of corti that is stimulated?
frequency
what is determined by higher central auditory nervous centers comparing sounds from both ears, requiring biaural hearing?
location
the auditory nerve is part of cranial nerve ___
8
what two parts does the auditory nerve connect?
cochlea
brainstem
where does the auditory nerve course through in the petrous temporal bone?
internal auditory meatus
what is the order of the auditory system within the brain?
cochlear nucleus
superior olivary complex
lateral leminiscus
inferior colliculus
medial geniculate body
auditory cortex
which type of hearing loss is due to sound being unable to reach cochlea and auditory nerve, such as wax, medications, or infection?
conductive hearing loss
which type of hearing loss is due to damage/abnormality of the cochlea and/or auditory nerve, such as drugs, presbycusis, noise induced?
sensorineural
