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Flashcards in Chapter 11 Deck (81):
1

what is the environmental stimuli for hearing?

pressure changes in the air

2

Two types of definitions for sound

physical definition: pressure changes in the air

perceptual definition: the experience we have when we hear

3

condensation

 

when air molecules are pushed together

 this causes an increase in air pressure

 

4

rarefaction

decreased density of air molecules

 causes a slight decrease in air pressure

5

sound wave

pattern of pressure changes in some kind of medium

6

how fast can sound waves travel through air?

through water?

340 meters per second

1,500 meters per second

7

what is the pattern of air pressure changes in the environment

what happens to molecules during these changes

what is transmitted in the end

they move outward

air molecules move back and forth but stay in about the same place

pattern changes 

8

pure tone

-what is it

-when do they occur

type of sound wave

when air pressure changes happen in a pattern of a sine wave

9

frequency

the number of cycles per second pressure changes repeat

10

amplitude

the size of pressure changes

11

4 examples of pure tones

whistleing

high pitched flute tones

tuning forks

computers

12

hertz (Hz)

-what is it

-what is it equivalent to

measure of frequency

1 Hz = 1 cycle per second

13

What range of frequencies can humans perceive?

20 - 20,000 Hz

14

Hertz is to amplitude as _____ is to _____

pitch, loudness

15

decibel (dB)

-what is it

-how is it used

a unit of sound

used to convert very large ranges of sound pressures into a smaller scale

16

opposite of pure tone

complex tone

17

periodic tone

a tone that has a repeating waveform

18

fundamental frequency

number of times the pattern of a tone repeats per second

19

harmonic

pure tones that are added up to create complex tone

20

first harmonic

-what is it

-what can it also be called

the pure tone with a frequency equal to the fundamental frequency of the overall tone

the fundamental of the tone

21

higher harmonics

pure tones with frequencies that are whole number multiples of the fundamental frequency

22

frequency spectra

representation of a tone's harmonic components

x-axis: frequency of each harmonic

y-axis: amplitude

23

what happens to the tone when one of the harmonics is removed

 

why does this happen

waveform changes, repetition rate stays the same

 

 

spacing between harmonics = repetition rate        when one of them is removed the spacing stays the same; still enough info about the fundamental frequency

24

loudness

-what is it

-what is it related to 

-how is it represented

perceptual quality

the level or amplitude of a sound

decibles

25

audibility curve

what is it (x and y axises)

what two things does it tell us (1) sounds we can hear

(2) where is threshold lowest

hearing threshold x frequency

can hear sounds between 20 Hz and 20,000 Hz

lowest between 2,000 and 4,000 Hz

26

auditory response area

-where is it on the curve

-what does it represent

above audibility curve

represents the area of tones we are able to hear

 

27

threshold of feeling

area on audibility curve

includes tones with such high amplitudes that we can feel them

28

what do equal loudness curves shoe

sound levels that create the same perception of loudness at different frequencies

29

what are at threshold levels like along the audibility curve

how does the perception of loudness change as you move above threshold on the audibility curve?

 can be very different for different frequencies

at certain levels different frequencies can have a similar loudness at the same decibel level

30

pitch

perceptual quality of sound

highs/lows - how we would order sounds on a music scale

31

tone height

how does it relate physically to the tone

the perceptual experience of increasing pitch

goes along with the increase in a tone's fundamental frequency

32

tone chroma

fundamental frequencies of tone chroma

notes with the same letter on a keyboard

fundamental frequencies are whole multiples of one another

33

what happens to frequencies as you move from octave to octave

they double

34

the effect of the missing fundamental

constancy of pitch

even when the fundamental harmonic or any other harmonics are taken out

35

periodicity pitch

what does this tell us about pitch

the pitch we perceive in tones with harmonics removed

pitch is determined by the repitition rate of the waveform, not by the presence of the fundamental frequency

36

timbre

quality that distinguishes two tones that have the same loudness, pitch, and duration but still sound different

37

attack and decay

 build up of sound at the beginning of a tone

  decrease in sound at the end of it

38

2 factors that cause musical instruments to have different timbres

different harmonics

the time course of attack and decay (hard to differentiate when these are cut out)

 

39

3 steps of the auditory system for hearing

  1. sound stimulus is delivered to the receptors
  2. transduction - pressure changes into electrical signals
  3. electric signals are processed to indicate qualities of the sound

 

40

Three divisions of the ear

Outer

Middle

Inner

41

Parts of the outer ear

pinna

auditory cannal

42

pinna

ear structure that sticks out of our head

43

auditory canal

-what is it

-how long

-what does it do

tubelike structure

~3cm long

protects middle ear structures

44

What structure does the auditory canal protect?

Where is it located?

What other way is it protected besides structurally?

 

tympanic membrane (the eardrum)

at the end of the canal

canal keeps this and middle ear at a constant temperature

45

2 functions of outer ear

protection of middle ear

enhancing sound intensities via resonance

46

resonance

when sound waves reflected back from closed end of  auditory canal interact with sound waves coming in

47

resonant frequency

 frequency that is reinforced the most during resonance

48

the amplifying effect of resonance in the auditory canal

which frequencies

whats notable about these frequencies

it increases the sound pressure level of frequencies between 1,000 and 5,000 Hz

(the most sensitive range of hearing)

49

middle ear

-size

-what does it do

-what does it contain

small cavity - 2 cubic cm

separates outer and inner ear

 ossicles and middle-ear muscles

50

3 components of the ossicles

malleus (hammer)

incus (anvil)

stapes (stirrup)

51

Describe how waves travel through the middle ear

3 parts

tympanic membrane sets malleus into vibration

Vibrations transmit to incus and then to stapes

Stapes transmit vibrations to inner ear by pushing on membrane over oval window

52

What structural quality of the inner ear poses a problem for transmitting sound vibrations to it?

It is filled with cochlear fluid whereas the outer and middle ears are filled with air

 

liquid is much denser

53

How do the ossicles help solve the problem of wave transmission from air to liquid

  1. concentrating the vibration of the tympanic membrane increases pressure
  2. it is hinged to create a lever action which amplifies

54

middle-ear muscles

where are they

when do they contract and why

what does this do

small muscles attached to ossicles

 at very high level sounds to dampen bone vibration

reduces transmission of low frequency sounds and prevents intense low frequencies to interfere with perception of higher ones

55

inner ear

cochlea

56

parts of the cochlea

3 parts

upper half - scala vestibuli

lower - scala tympani

seperated by cochlear partition

57

cochlea - base and apex

base - end near the stapes

apex - other end

58

organ of Corti

-where

-what does it contain

inside the cochlear partition

contains hair cell receptors

59

3 things found in the cochlear partition

  1. organ of Corti
  2. basilar membrane
  3. tectorial membrane

 

60

cilia

-what are they

-what do they do

thin things coming out on the tops of hair cells  

 

bend in response to pressure changes

61

two types of hair cells (rows, #, relation to tectorial membrane)

inner - 1 row, about 3,500; do not touch 

outer - 3 rows, 12,00; tallest row touches

62

basilar and tectorial membrane

basilar - membrane organ of Corti sits upon

tectorial - goes over the top of the hair cells

63

How does the motion of the oval window move through the cochlea?

3ish steps

  1. Vibrations transmitted to liquid inside
  2. Basilar membrane begins moving up and down
    1. Organ of corti goes up and down
    2. Tectorial membrane goes side to side
  3. Hair cells bend

 

64

In what ways are each type of hair cells bent?

outer - touching the tectorial membrane that is moving back and forth

inner - pressure waves in the liquid

65

Describe the ion flow of hearing

3 steps

reversal process

  1. tip links at the end of the cilia stretch and open ion channels
  2. positively charged potassium ions flow into hair cell
  3. neurotransmitters released

hair moves in opposite direction and tip links close

66

how does frequency affect electrical signal

auditory nerve fibers fire in synchrony with the rising and falling pressure of the tone

67

phase locking

neural firing at peak but not every single time it peaks

68

What may happen for nerve fibers during high frequency tones?

Some may not fire every time the pressure changes because of refractory periods

When some miss, others react, but reaction still always matches the frequency of the tone

69

phase locking occurs up to what level of frequency

5,000 Hz

70

traveling wave

the way the basilar membrane vibrates

like snapping a rope

71

What is the relationship between tone frequency and the vibration of the basilar membrane?

the places along the membrane that vibrate the most depend on the frequency of the sound

72

What have scientists indicated determines pitch?

-what is most important and at which frequencies

Mostly timing of nerve firing

 place information at frequencies above 5,000 Hz

73

pitch neurons

neurons that respond to a specific pitch; even when certain harmonics are removed

74

What aspect of hearing does the time of nerve firing play a role in 

-which sounds does this occur for and why

pitch perception

sense of pitch appears to only sounds below 5,000 Hz where phase locking occurs

75

what is phase locking

firing of impulses at peak of sound stimulus

76

What evidence indicates that tone is determined by periocity and not place of vibration (2)

you can remove first harmonic and it sounds the same

basilar membrane doesnt vibrate the same way but we still perceive it the same

77

When is place infomation important for pitch?

above 5,000 Hz

78

specificity coding theory

distributed coding theory

place theory

 

timing theory

79

place theory

frequency is indicated by the place along the Organ of Corti where nerve firing is highest

peak of a traveling wave depends on the frequency

80

place theory: where is the peak for low and high frequencies

low - max is at apex

high - max is at base

81

timing theory

frequency is also represented by rate/timing of firing

phase locking