Lecture 16

Question 1

Pinna helps with ___ ___

Answer 1

Pinna helps with sound location

Question 2

Auditory canal is a ___-like 3 cm long structure that protects the ___ ___ (ear drum) at the end of the canal

Answer 2

Auditory canal is a tube-like 3 cm long structure that protects the tympanic membrane (ear drum) at the end of the canal

Question 3

Resonance

Answer 3

occurs when sound waves that are reflected back from the tympanic membrane interact with sound waves entering the canal, which can reinforce (increase the intensity of) certain frequencies

Question 4

The auditory canal amplifies frequencies between 1,000 and 5,000 Hz (which is the canal’s ___ ___, or the frequency that is most reinforced)

Answer 4

The auditory canal amplifies frequencies between 1,000 and 5,000 Hz (which is the canal’s resonant frequency, or the frequency that is most reinforced)

Question 5

The __ __ is a two cubic centimetre cavity separating the inner ear from outer ear

Answer 5

The middle ear is a two cubic centimetre cavity separating the inner ear from outer ear

Question 6

The middle ear contains 3 __ (which are the smallest bones in the human body): ___, ___, and ___

Answer 6

The middle ear contains 3 ossicles (which are the smallest bones in the human body): malleus, incus, and stapes

Question 7

Malleus (hammer)

Answer 7

moves due to the vibration of the tympanic membrane (ear drum)

Question 8

Incus (anvil)

Answer 8

transmits vibrations of the malleus

Question 9

Stapes (stirrup)

Answer 9

transmits vibrations of the incus to the inner ear (via the oval window of the cochlea)

Question 10

While the outer and inner ear are filled with __, the inner ear is filled with ___ that is much denser than air. This causes pressure changes in __ to transmit __ into the denser medium (the __). The ossicles helps to amplify these vibrations for better transmission.

Answer 10

While the outer and inner ear are filled with air, the inner ear is filled with fluid that is much denser than air. This causes pressure changes in air to transmit poorly into the denser medium (the liquid). The ossicles helps to amplify these vibrations for better transmission.

Question 11

The middle ear muscles also ___ the ossicles’ vibrations to protect the inner ear from potentially damaging stimuli when exposed to ___ ___ sound waves

Answer 11

The middle ear muscles also dampen the ossicles’ vibrations to protect the inner ear from potentially damaging stimuli when exposed to high amplitude sound waves

Question 12

Two properties of the middle ear assist with amplifying the sound:
1) By ___ the vibrations of the large tympanic membrane onto the much smaller ___
2) By being hinged and therefore creating ‘___ action’ which amplifies a small force

Answer 12

Two properties of the middle ear assist with amplifying the sound:
1) By concentrating the vibrations of the large tympanic membrane onto the much smaller stapes
2) By being hinged and therefore creating ‘lever action’ which amplifies a small force

Question 13

Cochlea

Answer 13

main structure of the inner ear, and the location at which transduction of pressure waves occurs

Question 14

The cochlea is divided by the __ ___ that divides it into 2 sections: the upper half (Scala __) and the lower half (Scala __)

Answer 14

The cochlea is divided by the cochlear partition that divides it into 2 sections: the upper half (Scala vestibule) and the lower half (Scala tympani)

Question 15

___ of ___ is located within the cochlear partition and contains inner and outer hair cells, which are the receptors for hearing

Answer 15

Organ of Corti is located within the cochlear partition and contains inner and outer hair cells, which are the receptors for hearing

Question 16

___ ___ supports the organ of Corti and vibrates in respond to sound

Answer 16

Basilar membrane supports the organ of Corti and vibrates in respond to sound

Question 17

___ ___ extends over the hair cells

Answer 17

Tectorial membrane extends over the hair cells

Question 18

The ‘back and forth’ motion of the oval window transmits vibrations to the liquid inside the cochlea:

puts the basilar membrane into an ‘_____’ motion, puts the tectorial membrane into a ‘____’ motion

Answer 18

The ‘back and forth’ motion of the oval window transmits vibrations to the liquid inside the cochlea:

puts the basilar membrane into an ‘up-and-down’ motion, puts the tectorial membrane into a ‘back and forth’ motion

Question 19

___ (parts of the outer hair cells)bend in response to movement of organ of Corti and the tectorial membrane

Answer 19

Stereocilia (parts of the outer hair cells)bend in response to movement of organ of Corti and the tectorial membrane

Question 20

Movement in one direction opens ion channels in the ___ ___ (parts of the stereocilia). Movement in the other direction closes the ion channels

Answer 20

Movement in one direction opens ion channels in the tip links (parts of the stereocilia). Movement in the other direction closes the ion channels

Question 21

Phase locking

Answer 21

nerve fibres firing at/near peak of sound wave, and are thus “locked in phase”. Groups of fibres fire with periods of silent intervals, creating a pattern of firing. Carries temporal information that may assist with pitch perception

Question 22

Bekesy’s Place Theory of Hearing

Answer 22

proposed that the frequency of sound is indicated by the place on the organ of Corti that has the highest firing rate

Question 23

Bekesy noticed that the basilar membrane’s vibration was like a __ ___ (e.g. imagine holding a rope and ‘snapping’ it, then watching the resulting wave travel down the length of the rope)

Answer 23

Bekesy noticed that the basilar membrane’s vibration was like a travelling wave (e.g. imagine holding a rope and ‘snapping’ it, then watching the resulting wave travel down the length of the rope)

Question 24

Because the amount of displacement on the basilar membrane is a function of frequency, we can think of the cochlea as effectively functioning like a ___

Answer 24

Because the amount of displacement on the basilar membrane is a function of frequency, we can think of the cochlea as effectively functioning like a filter

Question 25

cochlea shows an orderly map of frequencies along its length, which can be referred to as __ organization

Answer 25

cochlea shows an orderly map of frequencies along its length, which can be referred to as tonotopic organization

Question 26

Apex responds best to __ frequencies

Answer 26

Apex responds best to low frequencies

Question 27

Base responds best to __ frequencies

Answer 27

Base responds best to high frequencies

Question 28

Pure tones can be used to determine the threshold for specific frequencies measured at single neurons, which can then be used to produce ___ ___ ___ curves

Answer 28

Pure tones can be used to determine the threshold for specific frequencies measured at single neurons, which can then be used to produce neural frequency tuning curves

Question 29

Frequency to which the neuron is most sensitive is the ___ ___

Answer 29

Frequency to which the neuron is most sensitive is the characteristic frequency

Question 30

New research with live membranes shows that the entire outer hair cells respond to sound by ___ ___ and a change in __

Answer 30

New research with live membranes shows that the entire outer hair cells respond to sound by slight tilting and a change in length

Question 31

Higher ___ = lower sensitivity = __ hearing

Answer 31

Higher threshold = lower sensitivity = worse hearing

Question 32

Place theory

Answer 32

suggests the pitch perception is based on the relation between a sound’s frequency and the place along the basilar membrane that is activated

Question 33

The effect of the missing fundamental could be explained by assuming the ___ also vibrate the membrane, and that the ___ of the intervals is informative of the fundamental

Answer 33

The effect of the missing fundamental could be explained by assuming the harmonics also vibrate the membrane, and that the spacing of the intervals is informative of the fundamental

Question 34

The lower harmonics produced by tones tend to create distinct neural responses, which are referred to as ___ harmonics

Answer 34

The lower harmonics produced by tones tend to create distinct neural responses, which are referred to as resolved harmonics

Question 35

Higher harmonics tend to create neural responses that are not clearly distinguishable, and are referred to as ___ harmonics

Answer 35

Higher harmonics tend to create neural responses that are not clearly distinguishable, and are referred to as unresolved harmonics

Question 36

Primary auditory cortex (auditory receiving areas or A1 in temporal lobe) can be divided up into 3 general subregions ….

Answer 36

1) Core area
2) Belt area
3) Parablet area

Question 37

Noise-induced hearing loss

Answer 37

acute exposure to very loud noises can severely damage the hair cells in the organ of Corti

Question 38

Hidden hearing loss

Answer 38

refers to situations in which individuals may have normal results e.g. thresholds in a standard hearing test using pure tones played in isolation, yet have difficulty perceiving more complex ‘real-world’ sounds

Question 39

If the hair cells are functioning normally yet the auditory nerve is not, this could produce ___ ___ ___

Answer 39

If the hair cells are functioning normally yet the auditory nerve is not, this could produce hidden hearing loss

Question 40

Presbycusis

Answer 40

results from the cumulative effects of exposure to noise over time, greatest loss at high frequencies, affects males more severely than females, can be caused by exposure to some drugs

Question 41

Cochlear implants are made up of

Answer 41

a microphone worn behind the ear, a sound processor, a transmitter mounted on the mastoid bone, a receiver surgically mounted on the mastoid bone

Question 42

DeCasper and Fifer found evidence that infants’ recognize their mother’s voice as early as ___ ___ after birth

Answer 42

DeCasper and Fifer found evidence that infants’ recognize their mother’s voice as early as 2 days after birth