The auditory system Flashcards

1
Q

What is a sound wave?

A

Vibrating particles passing vibrations onto the next particle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the peak of a sound wave?

A

Compressed air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the trough of a sound wave?

A

Rarefied air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is frequency?

A

Number of compressed or rarefied patches of air that pass our ears each second

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the units of frequency?

A

Hertz (Hz)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is intensity?

A

Air pressure difference between peaks and troughs (amplitude)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the units of intensity?

A

Decibels (dB)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What kind of scale is decibels?

A

Logarithmic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is the range of hearing for humans?

A

20 Hz to 20 000 Hz

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the 3 main regions of the ear?

A
  • Outer
  • Middle
  • Inner
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is included in the outer ear?

A

Pinna to the tympanic membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is the tympanic membrane?

A

Eardrum

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is the pinna?

A

Part of the ear that you can see

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is included in the middle ear?

A

Tympanic membrane to the oval window (air filled)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is included in the inner ear?

A

Cochlea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is the function of the outer ear?

A

Convolutions allow for sound localisation in the vertical plane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What are the 3 smallest bones in the body?

A

Ossicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What are the names of the ossicles?

A
  • Hammer (also malleus)
  • Anvil (also incus)
  • Stirrup (also stapes)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Where are the ossicles located?

A

Between the tympanic membrane and oval window

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which ossicle is attached to the tympanic membrane?

A

Hammer (malleus)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which ossicle is attached to the oval window?

A

Stirrup (stapes)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the connection like between the malleus and incus?

A

Rigid

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What is the connection like between the incus and stapes?

A

Flexible

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the purpose of the ossicles?

A

To concentrate the sound when it is transmitted to the cochlea

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Why does the sound need to be concentrated by the ossicles?

A
  • Cochlea is fluid-filled which has a higher impedance than air
  • Without the ossicles, not enough force would be generated by the sound to cause sufficient fluid movement in the cochlea
  • Ossicles overcome the impedance of the cochlear fluid
26
Q

What happens when the tympanic membrane is pushed inwards?

A
  • Malleus moves down which pushes incus forward, stapes pushes into oval window causing fluid to move through the cochlea
  • Fluid pushes out through the round window
27
Q

What happens when the tympanic membrane is pulled outwards?

A
  • Malleus moves up which pulls incus backwards, stapes pulls back so oval window moves out and cochlear fluid comes towards oval window
  • Round window pulls inwards
28
Q

What is the apex of the cochlea?

A

Helicotrema

29
Q

What are the 3 compartments of the cochlea?

A
  • Scala vestibuli
  • Scala media
  • Scala tympani
30
Q

Which direction does fluid move through the scala vestibuli?

A

From the oval window to the apex

31
Q

Which direction does fluid move through the scala tympani?

A

From the apex to the round window

32
Q

What is the fluid inside the scala vestibuli and scala tympani in the cochlea?

A

Perilymph

33
Q

Which sections of the ear are filled with perilymph?

A

Scala vestibuli and scala tympani

34
Q

What is the fluid inside the scala media?

A

Endolymph

35
Q

Which section of the cochlea is filled with endolymph?

A

Scala media

36
Q

What is special about endolymph?

A

High K+ content

37
Q

What do the hair cells rest on?

A

Basilar membrane

38
Q

What is the organ of Corti?

A

Auditory organ containing the basilar membrane and hair cells

39
Q

What are the 2 kinds of hair cells?

A

Outer and inner

40
Q

Which section of the basilar membrane detects high frequency sounds?

A

Bottom

41
Q

Which section of the basilar membrane detects low frequency sounds?

A

Apex

42
Q

Which part of the basilar membrane is stiff and narrow?

A

Bottom

43
Q

Which part of the basilar membrane is floppy and wide?

A

Apex

44
Q

What is the tonotopic map of the cochlea?

A

Base of the basilar membrane responds to high frequency sounds and the apex responds to low frequency

45
Q

What is the membrane which is on top of the hair cells?

A

Tectorial membrane

46
Q

Which hair cells transduce auditory information?

A

Inner hair cells

47
Q

What is the structure of the stereocilia on the hair cells?

A

3 rows of stereo cilia in ascending size

48
Q

What happens when the smaller stereocilia are pulled towards the taller stereocilia?

A

Hair cell depolarises

49
Q

What happens to the hair cells when the stapes pulls outwards?

A
  • Basilar membrane moves upwards
  • Stereocilia pushed towards tallest one
  • Hair cell depolarises
50
Q

What happens when the taller stereocilia are pushed towards the smaller stereocilia?

A

Hair cell hyperpolarises

51
Q

What happens to the hair cells when the stapes pushes inwards?

A
  • Basilar membrane moves downwards
  • Stereocilia pushed towards smallest one
  • Hair cell hyperpolarises
52
Q

Which section of the cochlea is the organ of Corti in?

A

Scala media

53
Q

What is the function of inner hair cells?

A

Transduce sound

54
Q

What connects the stereocilia?

A

Tip links

55
Q

How does high intensity sound cause hearing loss?

A

Breaks tip links between stereocilia

56
Q

What is the mechanoelectrical transducer channel called?

A

TMC1

57
Q

What happens in the hair cell when the short cilia are pulled towards the tall ones?

A
  • Pulling of the tip links opens TMC1
  • K+ from endolymph enters the hair cell and causes depolarisation
  • Voltage-gated Ca2+ channels open
  • Ca2+ causes exocytosis of vesicles containing glutamate
  • Glutamate binds to receptors on primary afferent neuron
58
Q

Which neurotransmitter is used in the auditory system?

A

Glutamate

59
Q

What happens in the hair cell when the tall cilia are pushed towards the small ones?

A
  • TMC1 is closed
  • Hair cell becomes hyperpolarised
  • No Ca2+ so no glutamate released
60
Q

What is the function of outer hair cells?

A

Amplify lower intensity sounds (quiet) by amplifying the movement of the cochlear fluid/basilar membrane

61
Q

How are outer hair cells electromotile?

A

When hyper/depolarised they become shorter/longer