06c: Peripheral Auditory System Flashcards Preview

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Flashcards in 06c: Peripheral Auditory System Deck (45):
1

Perceived loudness of sound reflects (X).

X = amplitude of pressure fluctuations

2

The Sound Pressure Level (SPL) is defined as:

20*log(P/Po)

3

SPL has which units?

dB

4

If the pressure of a sound wave is 100 times greater than reference level, the intensity would have which value?

SPL = 20*log(100) = 40 dB

5

For every increase in pressure by one order of magnitude, the intensity we perceive is increased by:

20 dB

6

Perceived pitch of sound reflects (X).

X = frequency

7

Frequency units.

Hz

8

Explain reason for "impedance mismatch" in (X) system?

X = auditory;

Air is less dense than inner ear fluid, so most E from incoming sound wave would be reflected back upon reaching interface

9

The (X) system overcomes "impedance mismatch" because (Y) is (Z) times greater than:

X = auditory;
Y = ear drum/tympanic membrane
Z = 20

Oval window/footplate of Stapes

10

Since the tympanic membrane's surface area is so much larger than (X), the (Y) is amplified correspondingly.

X = oval window
Y = force per unit area

11

The orientation and movement of middle ossicles bones provides (X) advantage factor of (Y).

X = mechanical;
Y = 1.5

12

T/F: sound arriving at inner ear through the skull passes the middle ear.

False

13

Ossicles are present in (external/middle/internal) ear. List them, from lateral to medial.

Middle

1. Malleus
2. Incus
3. Stapes

14

(X) is the site for transducing sound waves into neural impulses

X = cochlea

15

Cochlea composed of (X) number of (perpendicular/parallel) canals. List them, from top to bottom.

X = 3
Parallel;

1. Scala vestibuli
2. Scala media
3. Scala tympani

16

Which canals in cochlea contain perilymph, which is high in (X) ion?

Scala vestibuli and tympani

X = Na

17

Which canals in cochlea contain endolymph, which is high in (X) ion?

Scala media

X = K

18

Which canals in cochlea in contact with round window?

Scala tympani

19

Which canals in cochlea in contact with oval window?

Scala vestibuli

20

(Round/oval) window found at base of cochlea.

Both

21

Reissner's membrane separates:

Scala vestibuli from scala media

22

Basilar membrane separates:

Scala media from scala tympani

23

Name the structure at (base/apex) of cochlea that connects (X) and (Y) canals.

Apex;
X = scala vestibuli
Y = scala tympani

Helicotrema

24

(X) is the name of the sensory epithelium of the auditory system. It sits on top of (Y).

X = organ of corti
Y = basilar membrane

25

Base of HCs in auditory system are implanted in (X). Tips protrude into (Y).

X = organ of corti
Y = tectorial membrane

26

HCs in auditory system composed of:

Stereocilia only

27

Auditory system: depolarization when stereocilia bend toward (X).

X = tallest stereocilia

28

(X) membrane in inner ear is the one that vibrates in response to sound waves.

X = basilar

29

Stereocilia of HCs in auditory system are bathing in (peri/endo)lymph of (X) canal, which is (high/low) in K and has standing potential of (Y).

Endolymph;
X = scala media
High;
Y = +100 mV

30

Sound intensity is encoded in which way(s)?

1. Firing rate
2. Number of HCs (and afferent fibers) responding

31

Sound pitch is encoded in which way(s)?

Location of basilar membrane that is vibrating (between apex and base)

32

Sound with high (X) will vibrate (apex/base) of (Y) membrane.

X = frequency;
Base;
Y = basilar

33

Resonator theory is that which describes how (X) is encoded.

X = sound pitch/frequency

34

Each auditory afferent nerve has a preferred (X) that it's most sensitive to.

X = sound frequency

35

As a sound deviates further from an auditory nerve's preferred frequency, there's an (increase/decrease) in (X) at which the nerve can detect the sound.

Increase;
X = threshold of loudness (dB)

36

Auditory nerve fibers have a (more/less/equally) selective response to frequency of sound compared to the basilar membrane.

More selective (second filter)

37

"Second filter" tuning mechanism in auditory nerve fibers may be due to which phenomena?

1. Lateral inhibition
2. Mechanical and electrical resonance

38

(X) ion entering and depolarizing auditory hair cell from (perilymph/endolymph) is due to (chemical/electrical) gradient.

X = K
Endolymph; electrical

39

(X) ion leaving and repolarizing hair cell goes into (perilymph/endolymph) due to (chemical/electrical) gradient.

X = K
Perilymph;
Chemical

40

When HC is depolarized, due primarily to (X) ion (leaving/entering), which other key ion (leaves/enters) HC and helps in repolarization process.

X = K
Entering;
Ca enters

41

"Ringing" or electrical resonance in hair cells is dependent on which factor(s)?

1. Density of K and Ca channels in hair cell
2. Kinetics of calcium-gated K channels

42

HC toward apex of membrane will have (higher/lower) density of K/Ca channels with (faster/slower) calcium-gated K channels.

Lower; slower

43

(Inner/outer) HCs provide most, (X)%, of input to auditory nerve.

Inner;
X = over 95

44

(Inner/outer) HCs change shape to mechanically (dampen/amplify) (X).

Outer;
Amplify;
X = oscillatory movement of basilar membrane

45

In tinnitus, there's uncontrolled (X) of (Y), producing an actual measurable sound emitted by tympanic membrane.

X = cyclical contraction
Y = outer HCs