Ear Flashcards
Does chorda tympani run through the middle ear cavity?
Does facial?
yes
no
adjacent infection can spread from middle ear to
facial nerve
external ear components
pinna, external auditory meatus
innervation of the pinna
GSA sensory from auriculotemporal (v3)
lesser occipital and great auricular
auricular hematoma
trauma to pinna causeing hemorrhaging, if not evacuated and bandaged the scar tissue may grossly deform the auricle
skin tightly adherent to cartilage and bone in ear. can be very painful
blood supply to pinna
postirior auricular artery
superficial temporal a
sensory nerve to pinna
arnold’s nerve
casual removal of a mass of ear wax may
avulse the tympanic membrane and the ossicles
when infected, the furuncle is very painful due to
close adherence of skin to the underlying periosteum
tympanic membrane is tilted
forward, lateral and downward in the canal
so you can hear steps coming towards you
part of the eardrum that vibrates
pars tensa
three layers of tympanic membrane
outer epidermis
middle fibrous
inner mucous membrane
pars tensa is
fibrous layer in the middle between the epidermis and mucous membrane
outer epidermis of eardrum enervated by
GSA fibers from trigeminal and vagus
pars flaccida
absence of pars tens a in antero-superior quadrant of tympanic membrane
inner mucous membrane is innervated by
GVA fibers of glossopharyngeal nerve via the tympanic plexus
umbo
central concavity of tympanic membrane
anterior and posterior mallear folds formed by
what passes through these folds
inner mucous membrane on borders of pars flaccid
chorda tympani nerve
Facial nerve in the middle ear
NOT in the middle ear cavity, it is in its own bony canal.
ossicles are formed in what branchial arch
2nd
tensor tympani m formed from what branchial arch
1st arch. in relationship with the malleus and incus
auditory tube can be opened by
swallowing
cochlea is _____ to facial nerve
anterior
facial nerve passes between the
chochlea and the semicircular canals in the facial canal.
course of the facial nerve
leaves brainstem, travels laterally in internal auditory meatus befor entering facial canal
within the canal, geniculate ganglion is located above and medial to the promontory of the middle ear cavity.
at the level of the ganglion, the nerve turns sharply posteriorly and forms the external genu
then courses downward, sends a branch to stapedius m. and exits tstylomastoid foramen
muscles of middle ear cavity
tensor tympani
stapedius
Tensor tympani innervation and function
V3
tightens the tympanic membrane and attenuates its vibrations
stapedius m innervation and function
facial nerve
protective mechanism to prevent excessive movement of stapes due to loud sounds
Cochlear division of 8 innervates____
conveys what type of information?
the organ of corti (spiral organ)
auditory
vestibular division of 8 innervates____
conveys what information?
maculae utricle and sacule, and cristae ampullaris
static and dynamic position sense for equlibrium
inner ear blood supply
labryinthine artery
arteriosclerosis of labyrinthine artery
may result in vertigo nausea and other inner ear abnormaliteis
membraneous labyrinth is suspended in
bony structure or canal - bony labyrinth
endolymph is found in ______
perilymph is found in ______
membranous labyrinth
bony labyrinth
this flud has an anatomic and physiologic distinction
semicircular canals are found in
bony labyrinth
vestibule of bony labyrinth houses
utricle and saccule
elliptical cavity in vestibule houses
utricle
spherical cavity in vestibule houses
saccule
what taps on oval window to set up waves in fluid
stapes
electrolytes are different in endolymph so they can set up
depolarization
bone of bony labyrinth covers over the ____ and is extremely hard
the membranous labyrinth
semicircular ducts ar part of what labyrinth? suspended in?
membranous. suspended in semicircular canals of bony labyrinth
crista ampulalaris detects
angular acceleration
utricle and saccule are located in
vestibule of osseous labyrinth
utricle and saccule are connected to each other
by utricle and saccular ducts - join together to form endolymphatic duct
macula utricle detects
linear acclerateion
macula saccule detects
low frequency vibrations
Helical shaped bony tube similar in shape to the shell of a snail
cochlea
inside the cochlea is the
cochlear duct
inside the cochlear duct is the
organ of corti
bony core of chochlea=
modiolus
what passes through the modiolus
choclear nerve
projects from the modiolus like the threads of a screw
spiral lamina
organ of corti inside
the cochlear duct
organ of corti contains
receptors for hearing
hair cells are arranged
tonotopically - to be able to respond to certain frequency of sound.
prolonged exposure to excessive amounts of nose and or music may lead to
partial destruction of the oran of coti. ischemic necrosis may be one of the mechanisms.
