LEC65: Our Ears Flashcards
greek, latin, olde english, pinna for ear?
greek: oto (otic)
latin: auris (auricular)
olde english: eare
pinna: from latin, feather, wing, fin
identify the temporal bone
parts of the temporal bone?
squamosal
zygomatic
mastoid
tympanic
what is within temporal bone?
sensory organs for balance and hearing
what connects to styloid process of temporal bone?
stylyhyoid ligament
stylomandibular ligament
styloglossus m (XII)
stylohyoid m (VII)
stylopharyngeus m (IX)
what is different about a baby’s temporal bone?
no mastoid process - it’s a developmental feature
where does internal acoustic meatus open?
into petrous part of temporal bone
which region of skull is temporal bone in?
middle cranial fossa
what is within the mastoid process here?
mastoid air cells
neumatized bone in the mastoid process
bone lessens with aging there - normal - air circulates. but can have infection spread here.
what provides sensory innervation to inner ear canal? nerve and fiber type
what other nerves do you find in the inner ear canal?
GSA of CN VII, facial n
also see vestibular nerve, cochlear nerve - balance
if facial nerve is knocked out when exits internal acoustic meatus, what is lost?
all function of VII
if VII is knocked out distal to greater petrosal nerve, what remains / is lost?
retain lacrimal gland GVE
lose sublingual/submandibular gland GVE
lose taste to anterior 2/3 tongue SVA
lose facial expression SVE
if VII is knocked out distal to chorda tympani, what is retained/lost?
retain:
lacrimal GVE (greater petrosal n)
sensation of inner ear GSA (n to stapedius)
taste to anterior 2/3 tongue SVA submandibular, sublingual glands’ GVE (chorda tympani)
lose:
facial expression SVE
sensory ganglion of facial n?
geniculate ganglion
where do motor branches of facial n traverse?
across parotid gland
then span out, do mm of facial expression
what are our 6 ears?
external, middle, inner on each side of the head
boundaries of each part of ear?
external: pinna - canal - tympanic membrane
middle: tympanic membrane - oval window
inner: deep w/in crevices of petrous
parts of external ear?
1) auricle aka pinna - what we see on outside
2) external acoustic meatus - external ear canal, leads to tympanic membrane
ID: helix, anti-helix, tragus, concha, pinna
first arch syndrome re: ear? what might result?
poor developed meckel’s cartilage
poorly developed pinna
mandible underdeveloped
functions of external ear?
capture, direct, amplify sound
dissipate heat
communicate / mood signaling
what provides auricular sensation?
V - auriculotemporal branch
VII - posteiror canal wall
IX - medial, inner part of tympanic membrane (via tympanic n)
X - most of ear canal, part of outer surface of tympanic membrane (auricular br)
C2, C3 - greater auricular n
C2 - lesser occipital n
where is sexual stimulation on ear? sexual suppression?
what causes cauliflower ear?
blows, damage that separate cartilage of pinna from surrounding tissue
tissue fills with fluid so difficult for blood or other serous fluid to escape
wax function in ears?
catches things coming in
works w/ sebaceous gland, keeps tympanic membrane moist, lubricated
hairs sticking in to sebaceous glands
ceruminous glands v important to give moistening
what is otitis externa
common, inflammation with external ear
why might you cough when inserting something into the ear?
because major innervation is from a branch of X, vagus
this is vagal response
what is otomorphology
study of the appearnce of the external ear
every person’s is different
can be used as a fingerprint substitute
where is middle ear? what is its main property?
air-filled space
from tympanicmembrane laterally to lateral wall of inner ear medially
communicates w/ mastoid air cells & pharyngotympanic (eustachian) tube
identify: pinna, ear canal, eardrum, middle ear, inner ear, eustachian tube
ossicles of middle ear?
malleus
incus
stapes
what is tympanic membrane a remnant of?
pharyngeal pouch of 1st branchial arch
identify chorda tympani, incus, handle of malleus
identify malleus
what is the difference
what is otitis media
build up of pressure in the middle ear, causes ear infection
very painful
what might chronic otitis media cause?
tear in the tympanic membrane (ear drum)
may effect malleus, may effect entire hearing mechanism, may have scaring on tympanic membrane
muscles of inner ear, their innervation, branchial arch derivation, function?
1) tensor tympani - V - arch 1 - dampen sounds, such as those produced from chewing
2) stapedius - VII - arch 2 - stabilize the stapes
how does sound move from outside > inside?
sound through ear canal > hits tympanic membrane
tympanic membrane vibrates, virbation > malleus
malleus passes vibration to incus, passes virbation to stapes > voal window
> inner ear fluids
what is smallest bone in human body?
stapes!
branchial arch of upper portion of malleus and incus?
branchial arch I
branchial arch of lower part of malleus and incus?
branchial arch II
branchial arch of arcus of stapes?
arch II
nerve of branchial arch II?
chorda tympani
what are the joints between the ossicles called? what type of joints?
synovial joints:
1) incudomaller (malleus-incus)
2) incudostapedeal (incus-stapes)
what is otosclerosis? what’s result?
if footplate of stapes becomes fused to oval window
lose hearing
what part of eustachian tube enters middle ear?
bony portion of eustachian tube > middle ear, at nasopharynx, at rear of nasal cavity
components of eustachian tube?
bony and cartilagenous portions
function of eustachian tube?
does aeration- equilibration of pressure in middle ear
describe difference between child/adult eustachian tube
child’s tube is horizontal, so children get infection easily
adults have more vertical tubes, so less likely to get otisis media
most common childhood ailment in the US?
middle ear disease, otitis media
areas of inner ear?
1) bony cavities (bony labyrinth)
2) membranous ducts & sacs (membranous labyrinth)
what does bony labyrinth contain?
vestibule, semicircular canals, cochlea
cavities lined w/ periosteum, contain perilymph
what does membranous labyrinth contain?
semicircular ducts, cochlear duct, utricle, saccule
spaces lined w/ endolymph
where is inner ear lodged?
deep within petrous bone
interaction btwn oval and round windows?
foot of stapes pushe in on oval window > helps push fluid around
round window pushes out, opposes action
functional elements of inner ear?
hair cells
what is on top of hair cells of inner ear? fxn?
stereocilia
highly sensitive, so pick up pressurs and convey info back to brain
have these in semicircular canal, cochlea
how many semicircular canals?
3 on each side of head
types of hearing loss
1) conductive hearing loss
2) sensorineural hearing loss
what is conductive hearing loss caused by, how does it present?
caused by piercing, related activities
failure in efficient conduction of sound waves thru outer ear, tympanic membrane, or middle ear
what is sensorineural hearing loss caused by, what does it damage?
caused by damage to hair cells - ie rock concerts - or diseas or brain trauma
damages: cochlear n, inner ear hair cells, and/or brain
nerves > inner ear?
VII, facial
VIII, vestibulocochlear
presbycusis?
major presentaiton of sensorineural hearing loss
age-related hearing loss
extremely common
how do cochlear implants work?
insert into cochlea
stimulates damaged hair cells > stimulates back to nerves
vestibular system diseases examples? what do we know about them?
balance disorder such as meniere’s disease, labyrinthitis, vertigo
know fluid compositions in perilymph and endolymph are problematic but don’t understand disease process
what is our oldest evolutionary sense?
balance
