9. Anatomy of Hearing Flashcards
Components of the Outer Ear
Temporal Bone
Left Cochlea
Brain
Hearing system is a
transducer
What energies are involved in the hearing system? What is the relation?
Acoustic and electrochemical energy
Transducting: acoustic energy is converted into electrochemical energy
Temporal bone contains
middle and inner ear
Audition
process associated with hearing
Transduction
ear converts acoustic energy into electrochemical energy
Auditory mechanism
inner ear
middle ear
outer ear
auditory pathway
Outer ear aka
pinna aka auricle
Components
Helix Antihelix Concha Scaphoid Fossa Crura Anthelicis Trianglualr Fossa
Role of Outer Ear
collects sound; localizes sound in space; captures sound energy
Parts of Concha
Concha Auriculae
Cymba Conchae
Cavum Conchae
Exterior area of ear
Targus
Antitargus
Intertragic Incisure
Lobule (Lobe)
Ear Canal
External Auditory Meatus (EAM)
EAM
External Auditory Meatus aka Ear Canal
EAM is ____ -shaped
S
How much of EAM is cartilage?
1/3 (lateral)
How much of EAM is temporal bone?
2/3 (medial)
Tympanic membrane (TM)
Ear Drum
Ear Drum
Tympanic membrane (TM)
What shape is the TM?
Oval
What are the three layers of tissue of the TM?
Cuticular layer
Fibrous layer
Mucous layer
Outer tissue layer of TM
Cuticular layer - continuation of epithelial lining of EAM and pinna
Intermediate tissue of TM
Fibrous layer
deep - circular fibers, periphery of membrane
superficial - fibers radiate out of handle of malleus to periphery
Inner tissue of TM
Mucous layer
continuous with mucosa of middle ear
Pars flaccida
superior to malleus
Manubrium malli
points of attachment exterior TM
Umbo
most distal attachement of manubrium
Cone of Light
Tensed membrane
Result of tension arising from attachment of manubrium to TM
Cone of Light
Middle Ear Cavity
houses middle ear ossicles
Medial wall of MEC
separates middle ear from cochlea
promontory of MEC
bulge from basal turn of cochlea
oval window of MEC
stapes footplate fits into space; lateral wall of vestible that links three osseous semicircular canals by apertures
lateral semicircular canal
part of vestibular system to determine position in space
shaking head “no”
body rotation
aeration
auditory tube brings in oxygen to middle ear (ONLY WAY)
Auditory tube
equalizes pressure differences between atmposphere and middle ear space
Auditory tube is connected to ______ in ____ and ____ orientation
nasopharynx
medially
anteriorly
Jugular bulb
underneath middle ear cavity floor
Interaction of these three canals allows brain to orient body’s position and orientation in 3D space
osseous semicircular canals
Anterior semicircular canal
side-to-side movement
head moving toward shoulders
posterior semicircular canal
nodding head yes
How does auditory system develop overall sense of rotation?
Anterior semicircular canal of one ear is parallel to posterior canal of other ear
ampulla
sensory organ for movement
inertia
responsible for stability and shape of canals
What structure houses the sensory organ for hearing?
Cochlea
What structure houses the sensory organs for balance?
Vestibular organ
The ___ of each semicircular canal houses the sensory mechanism for that canal
Ampulla
Cochlea
houses sensory organs for hearing
Cochlea coil makes just less(fewer) than ___ turns from base to apex
3
Modiolus
fibers of VIII vestibulocochlear nerve passes through perforation
Internal auditory meatus
VII facial nerve enters cranial activity
VIII vestibulocochlear nerve exits
temporal bone and enters cranial space
Vestibular organ
house sensory organs for balance
scala vestibuli
begins at vestibule and becomes inner part of spiral
how does scala vestibuli connect with middle ear space?
oval window
scala media
between vestibuli and tympani
endolymph
inner labyrinth fluid
perilympth
outer labyrinth fluid
Helicotrema
connects scala vestibuli and scala tympani
how does scala tympani connect with middle ear?
round window
The ___ of each semiciruclar canal houses the sensory mechanism of that canal
ampulla
Stapes footplate
fits in oval window and pushes on fluid
Fluid-filled sac rests within cavity of osseous labyrinth
Membranous labyrinth
Fluid within membranous labyrinth
endolymph
Fluid outside of the membranous labyrinth
perilymph
Houses sensory organ of each semicircular canal
ampulla
found in each ampulla
crista ampularis
overlays each crista ampularis
cupola
Many ___ protrude from each hair cell
sterocilia
One ___ protrudes from each hair cell
kinocilium
The ___ and ___ are within the membranous vestibule
saccule and utricle
what are the three bones in the ossicular chain?
Malleus
Incus
Stapes
which muscle looks like a hammer?
malleus
which muscle looks like an anvil?
incus
which muscle looks like a stirrup?
stapes
ossicles are ___ to the tympanic membrane
medial
produced by the articulation of the lateral process within the tympanic membrane
pars flaccida
forms articulation between malleus and incus
malleoincudal joint
point of articulation of incus and stapes
lenticular process
muscle arising from posterior wall of middle ear cavity
stapedius muscle
muscle that tenses tympanic membrane
tensor tympani muscle
efferent innervation of the hair cell is
inhibitory
rests atop the hair cells
tectorial membrane
organ of corti rests on
basilar membrane
Deiters’ Cells
bed that four rows of hair cells rest on
Where are inner and outer hair cells located?
organ of corti
How many cells and rows in inner hair cells?
one row; 3500 cells
how many cells and rows in outer hair cells?
three rows; 12,000 cells
“many-to-one” innervation
inner hair cell innervates as many as 10 VIII nerve fibers; “10 times as many votes”
“one-to-many” innervation
outer hair cells
Shares innervation with 10 other outer hair cells that are all innervated by SAME VIII nerve fiber