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MVST1B NHB > Hearing L2 > Flashcards

Hearing L2 Flashcards

1
Q

T Or F?

The pattern of vibration is not dependent on which end of the cochlea is stimulated.

A

T

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2
Q

what are otoacoustic emissions

A

sound emmisions from the inner ear

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3
Q

are the outer hair cells capable of shape changes?

A

yes

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4
Q

OHCs are capable of shape changes - depolarisation of the cell causes length ______; hyperpolarisation of the cell causes length _______.

A

OHCs are capable of shape changes - depolarisation of the cell causes length decreases; hyperpolarisation of the cell causes length increases.

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5
Q

what happens when outer hari cells stop working well?

A

With total loss of OHC function there is a ~ 55 dB loss in thresholds.

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6
Q

what are the OHC responsible for?

A

sensitivity, sharpness of tuning, and oto-acoustic emissions

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7
Q

role of the iHC?

A

The inner hair cells (IHCs) act to transduce the mechanical events in the cochlea to electrical events in auditory-nerve fibres

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8
Q

how are the OHC involved in a feedback mechanism?

A
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9
Q

describe the The tip-link hypothesis of mechanotransduction

A

stereocilia are stretched towards the tallest stereocilia (or kinocilium in the vestibular apparatus) the probability of mechanically-gated channels opening increases; if they are stretched away from the tallest stereocilia the probability of them closing increases

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10
Q
A
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11
Q

where is teh alrgest current changes in hair cells?

A

at the tips of the steocilia

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12
Q

whats the predominant ion in the endolymph

A

K+

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13
Q

which ion is likely to carry the transucer current in hair cells?

A

K+

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14
Q

describe the K+ gradient for hair cells

A

The resting membrane potential of the cell (-50 mV) coupled with the large endocochlear potential (EP) of +100 mV gives a total gradient of 150 mV

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15
Q

what controls the compositiong of the endolymph?

A

Stria vascularis.

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16
Q
A
17
Q

what is meant by presbycusis

A

Our hearing thresholds elevate with increasing age (presbycusis)

18
Q

Thresholds for both men and women are _______- in the high frequencies than the lower frequencies.

A

Thresholds for both men and women are poorer in the high frequencies than the lower frequencies.

19
Q
A
20
Q

The greatest factor underlying
presbycusis appears to be …..

A

The greatest factor underlying presbycusis appears to be the loss of the endocochlear potential arising from lateral wall degeneration with age.

21
Q

how can we selectively lower the EP in one ear?

A

To test this hypothesis, it is possible to selectively lower the EP in just one ear by application of furosemide to the round window.

The resulting threshold loss seen with a reduction in the EP mimics that seen presbycusis; a relatively flat loss at low frequencies and a sloping loss at high frequencies.

22
Q

descrieb Otoacoustic emissions (OAEs)

A
  • Sounds that may be measured in the external auditory meatus
  • may be ovoked by sound or occur spontaneously
  • strongest piece of evidence for an active process
  • Patients with a significant sensorineural hearing loss lack OAEs.

*

23
Q

when are OAEs useful?

A

The measurement of emissions is particularly useful in neonates where it is difficult to establish the absence of hearing

24
Q

Distortion product evoked otoacoustic emissions (DPOAEs) are generated with the presentation of…..

A

Distortion product evoked otoacoustic emissions (DPOAEs) are generated with the presentation of two tones (aka the primaries, f1 and f2) and the largest of these emissions occurs at the frequency 2f1 – f2.

25
Q

compare inner and outer hair cells

A
26
Q

how do inner hair cells interact with the auditory nerve cells?

A

Inner hair cells release glutamate from ribbon synapses that act on AMPA receptors on the primary afferents (i.e. the auditory nerve fibres)

27
Q

Temporal adaptation in a high spontaneous rate auditory nerve fibre

describe the process of adaptation

A

Adaptation to a tone burst probably takes place at the hair cell/afferent fibre synapse

28
Q

how can we think of the output from the auditory nerve?

A

The output of the auditory nerve can be thought of as a set of parallel, overlapping, bandpass filters.

filters are narrower at higher frequencies.

29
Q

how do we calculate the Q10dB

A
30
Q

example of a QdB10 calculation

A
31
Q

as the charactersitic frquency increases, the Q10dB ?

increases or decreases

A

increases

32
Q

what is frequency resolution?

A

Frequency resolution (the ability to detect one frequency component of a multi-frequency complex stimulus, when all components are presented simultaneously)

33
Q

where is frequency resolution determined?

A

at the level of the basilar membrane.

That is, the psychophysical bandwidths and the neural bandwidths recorded in the same species overlap

34
Q

fat

A

mamba

another tough deck

35
Q
A

MVST1B NHB (25 decks)

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