Test 2: Lecture 17 Auditory

Question 1

higher air pressure creates ___

Answer 1

condensation

Question 2

lower air pressure creates ___

Answer 2

rarefaction

Question 3

change is pitch changes ___

Answer 3

frequency

Question 4

change in loudness changes

Answer 4

the amplitude (magnitude of the wave)

Question 5

the peak to peak variation in pressure gives impression of ___

Answer 5

loudness

Question 6

the frequency of the sinusoidal pressure wave will change the ___

Answer 6

pitch

cycles per sec = Hertz

Question 7

sound is measured in

Answer 7

dB (decibels)

Bel is one log unit

measurement relative to 20 microPascals

0 dB is threshold for humans at 1-4 kHz

Question 8

complex sound leads to the ___

Answer 8

combination of all sound waves into a sum sine wave that can be understood by the brain

Question 9

auditory transduction

Answer 9

sound waves into electrical signals that can be interpreted by the brain

Question 10

bones of the inner ear

Answer 10

auditory ossicles

malleus, incus and stapes

Question 11

___ hold the inner ear bones in place

Answer 11

anterior malleal ligament

posterior incudal ligament

tendon of the tensor tympani muscle

Question 12

footplate of the stapes sends vibrations into the ___

Answer 12

oval window of the bony labyrinth

Question 13

bony labyrinth is filled with a fluid called ___

Answer 13

perilymph

Question 14

flexibility of the ___ allows vibrations of the stapes to move the perilymph

Answer 14

round window

Question 15

corridor to the round window is found in the spiral portion called the ___

Answer 15

cochlea

Question 16

vibrations ascending to the apex of the cochlea by the

Answer 16

scala vestibuli

Question 17

vibrations descending from the apex of the cochlea to the round window by the

Answer 17

scala tympani

Question 18

___ is in between the scala vestibuli and the scala tympani

Answer 18

cochlear duct

Question 19

cochlear duct is filled with

Answer 19

endolymph

Question 20

membrane on top of the cochlear duct

Answer 20

reissners membrane

Question 21

membrane below the cochlear duct

Answer 21

basilar membrane

Question 22

___ is found on the basilar membrane of the cochlear duct

Answer 22

organ of corti

Question 23

nerve impulses from the organ of corti to the brain are via the ___nerve

Answer 23

cochlear

Question 24

hair cells within the organ of corti are covered by ___

Answer 24

tectorial membrane

Question 25

lower frequencies vibrate the basilar membrane closer to the ___ of the cochlea

Answer 25

apex

Question 26

higher frequencies vibrate the basilar membrane closer to the ___ of the cochlea

Answer 26

base

Question 27

parts of the labyrinth

Answer 27

Bony
• series of channels in bone

• envelops membranous labyrinth

Membranous
• soft tissue contain sensory cells for hearing and balance

• dorsal is vestibular
– semi-circular canals, utricle, and sacculus
• ventral is auditory
– cochlea

Question 28

movement of sound through the cochlea?

Answer 28

in through footplate of the stapes

up the scala vestibuli

down the scala tympani and out of the round window

Question 29

another name for cochlear duct

Answer 29

scala media filled with endolymph

Question 30

what part of the cochlear is filled with endolymph

and with perilymph?

Answer 30

endolymph → scale media (cochlear duct)

perilymph → scala vestibuli and scala tympani

Question 31

apical surface sensory cells of the organ of corti are bathes in intracellular like ___

Answer 31

ionic environment → high K and low Na

Question 32

there are ___ row of outer hair cells, and ___ row of inner hair cells in the organ of corti

Answer 32

3

1

Question 33

hair cell are ___ cells

Answer 33

mechano-sensory

Question 34

the afferent and efferent cells of the organ or corti are

Answer 34

afferent → inner

efferent → outer

Question 35

hair cells

Answer 35

found in the organ of corti

characteristic sensory hairs or stereocilia on apical surface

» typical organized in 3 rows of descending height

communicate with overlying tectorial membrane

Question 36

___ are essential to the transduction of sound

Answer 36

tip links on the stereocilla

will bind together the stereocilia of the hair bundle

Question 37

deflection of hairs toward the tallest hair

Answer 37

depolarization

Question 38

deflection of hairs away from the tallest hairs

Answer 38

hyperpolarization

Question 39

asymmetric process excitatory

Answer 39

inhibitory

Question 40

transduction channels are found near the tip of the ___ and are ___ channels

Answer 40

sterocilia

non-specific cationic channels

Question 41

afferent fiber to the brain are made of __

Answer 41

inner hair cells contracted by ∼10

contract about 3 outer hair cells

specialized synapses to allow high and prolonged rates of synaptic transmission

Question 42

outer hair cells

Answer 42

Both sensory and motor elements

• OHC are motile!
– contraction and elongation
• induced by voltage changes or inhibitory NT release

– modifies cochlear mechanics

– serves to sharpen cochlear frequency selectivity

– “cochlear amplifier”

Question 43

loss of hearing is caused by ___

Answer 43

damage to hair cells

typical cause of sensorineural hearing loss
– drug insults (aminoglycosides)

– viral infection

– degeneration of genetic origin

– acoustic overstimulation
» break tip links or disrupt actin core - ineffective transduction

» hair cell death - excito-toxicity

Question 44

acoustic overstimulation such as sat a concert will lead to ___

Answer 44

breaking tip links or disrupt actin core → can’t transduce wound

will eventually reform

Question 45

middle ear muscles

Answer 45

tensor tympani

stapedius

Question 46

___ collect and focus sound to the tympanic membrane

Answer 46

outer ear