L3 audition Flashcards
what are the 4 features of sound?
Amplitude
Frequency
Phase
Waveform
What do perceptions of sound correspond to?
loudness and pitch
what is the most sensitive threshold for humans?
2000-5000 Hz
What is the threshold for uncomfortable loudness?
100 dB
What is the threshold for painful loudness?
120-140
What are the fxns of the external ear?
protection
sound gathering
sound localization and elevation detection
What does the middle ear consist of?
malleus
incus
stapes
What is the stapes?
smallest bone that pounds on the oval window
What is the fxn of the middle ear?
impedance matching
How much sound would be gained w a middle ear?
34 dB
What is the area advantage?
27 dB
What is the ossicular lever action?
1.3 dB
What is the curved membrane buckling mechanism?
6 dB
What is the effect of the stapes pounding on the oval window?
fluid in the cochlea is displaced
Where is perilymph found in the inner ear?
scala vestibuli
scala tympani
What are the three parts of the cochlea
scala tympani
scala media
scala vestibuli
Where would be the maximum displacement of high frequencies in the cochlea?
the base
Where would be the maximum displacement of low frequencies in the cochlea?
the apex
What makes of the organ of corti?
basilar membrane
3 rows of outer hairs
1 row of inner cells
supporting cells
What structure covers the apical matrix of the organ of corti?
tectorial membrane
T/F the tectorial membrane is not part of the organ of corti
True
The tectorial membrane covers it, but it is not considered part of the organ of corti
What is generated when the basilar membrane move upward?
shear force
What happens to the stereocilia when the basilar membrane moves in the downward direction?
they bend in the medial direction
What is the result of medial bending of the stereocilia?
MET channels close and hair cells are repolarized
What are the two types of hair cells?
outer and inner
What is the role of outer hair cells ?
amplify sound
What is the role of inner hair cells?
transduce sound
….. cells are cylindrical shaped and ….. cells are flask shaped
Outer, inner
Activation/inhibition of an PHC causes it to change length. By stretch what protein?
Prestin proteins
they allow for recoil
What is the most common type of permanent hearing loss?
damage to OHCs
Activation of IHC release NT to what neuron?
CN VIII
vestibular cochlear
What type of fibers are afferents from CNVIII?
Type 1, assoc w IHC
What type of fibers are efferents from CNVIII that can modify sound?
Type II assoc w OHC
Where is the cochlear nucleus located
in the medulla
What are the main fxns of the cochlear nucleus?
relay signal to SOC
analyze comples signals and send it to Inf. colliculus
Where is the sup. olivary complex located?
pons
Which two nuclei are involved in sound localization in the SOC?
Lateral sup. Olive
Medial sup. Olive
LSO is the localization of what frequency?
high frequency
MSO is the localization of what frequency?
low frequency
How does the LSO localize high frequency
using sound differences
How does the MSO localize low frequency
time differences
Where is the inferior colliculus located?
midbrain
What coordinates the auditory and visual responses w/ the sup. colliculus?
Inferior colliculus
What auditory reflexes is the IC involved in?
auditory startle reflex
head turn response
Where is the medial geniculate body located?
In the thalamus
Where does the highest level of sound processing occur?
auditory cortex
What are the components of the olivocochlear bundles
Uncrossed and crossed olivocochlear bundle
Auditory memory, complex auditory discrimination, motor responses, and concepts about auditory stimuli are characteristic of what brain structure?
Auditory cortex
What hair cells are the UOCB assc w?
LSO, inner hair cells
What hair cells are the COCB assc w?
MSO, outer hair cells
