Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
35 Cards in this Set
- Front
- Back
|
pinna/auricle
|
-outer portion of ear
-collects sound |
|
|
external auditory meatus (EAM)
|
-funnels sound into tympanic membrane
-S-shaped -more constricted at area of bone & cartilage as sound is localized |
|
|
frequencies most enhanced by outer ear
|
1500-1800 Hz
|
|
|
tympanic membrane (TM)
|
-eardrum
-boundary between outer and middle ear |
|
|
ossicles
|
-maleus
-incus -stapes -used for impedance matching |
|
|
oval window
|
entry to the cochlea
|
|
|
impedance
|
-the way your eardrum is going to move
-P=F/A -increase F & P ==> decrease A |
|
|
three types of impedance matching mechanisms
|
-lever difference: 2 dB
-buckling difference: 4-6 dB -area difference: 25 dB |
|
|
lever difference
|
-2 dB
-traveling through ossicular chain ==> amplification -small force applied to lever of incus (mabubrium) ==> large force on long arm of lever |
|
|
buckling difference
|
-4-6 dB
-how eardrum changes its shape in response to different frequencis |
|
|
area difference
|
-25 dB
-area difference between TM and oval window -going from big, localizing to small area |
|
|
effective area of tympanic membrane
|
55mm sq.
|
|
|
effective area of oval window
|
3.2 mm sq.
|
|
|
acoustical gain to the area
|
17:1
associated with 25 dB |
|
|
dB of gain in middle ear lever
|
2 dB
|
|
|
tonotopic
|
-high frequencies perceived at one end, high frequencies perceived at other end
|
|
|
basilar membrane
|
-base: smaller, stiffer, thinner, lighter
-apex: bigger, less stiff, thicker, heavier |
|
|
auditory pathway
|
cochlear nucleus ==> superior olivary complex ==> inferior colliculus ==> medial geniculate body ==> temporal lobe
|
|
|
tympanic muscles
|
-muscles of middle ear attached to ossicles
-protect middle ear from damage -stapedius -tensor tympani |
|
|
eustachian tube
|
-entryway into pharynx
-purpose: ventilation -inferior border of middle ear |
|
|
which cranial nerve is the stapedius associated with?
|
VII Cranial Nerve: Facial Nerve
|
|
|
vastibular system
|
accelorometer in temporal bone, important for balance
|
|
|
round window
|
separates middle ear and scala tympani
|
|
|
two portions of cochlea
|
-osseous portion
-membranous portion - embedded within osseous portion |
|
|
osseous portion of cochlea
|
-bony portion
-divided into two chambers by spiral lamina -core of bony portion: modiolus |
|
|
liquid associated with membranous structures
|
endolymph
|
|
|
liquid associated with bony structures
|
perilymph
|
|
|
helicotrema
|
region in inner ear where scala vestibuli and scala tympani communicate
|
|
|
outer hair cells
|
13,500
three rows |
|
|
inner hair cells
|
3,500
one row |
|
|
tectoral membrane
|
-contains outer hair cells
-fibrogelatenous |
|
|
cochlear nuclus
|
-first stop in auditory pathway
-processes ipsilateral information -deals with timing and loudness |
|
|
joint between malleus and incus
|
malleoincudal joint
|
|
|
joint between incus and stapes
|
incudostapedial joint
|
|
|
% of auditory nerve fibers devoted to outer vs. inner hair cells
|
-outer hair cells: 5%
-inner hair cells: 95% |
