hearing

Question 1

what is relationship between compression and rarefaction?

Answer 1

an oscillating object will cause air to become more and less dense

Question 2

what is the wavelength equation?

Answer 2

wavelength = velocity / frequency

Question 3

what is the standard/mean hearing threshold ?

Answer 3

10ˉ12 WMˉ2

Question 4

what is the range of human hearing frequency and amplitude?

Answer 4

frequency - 20-20000Hz

Amplitude - 0-140dB

Question 5

what can be defined through tuning curves ?

Answer 5

certain neurons have different frequency responsiveness

Question 6

name the 3 parts of the ear

Answer 6

outer - ear drum

middle - ossicles

inner - cochlea

Question 7

what does the ossicle bone do?

Answer 7

pushes against the oval windows

the bottom window allows flexibility

Question 8

in what way does the middle ear act as a lever?

Answer 8

converts high amplitude force motion at ear drum into low force motion at the oval window
- vice versa

Question 9

what is impedance matching ?

Answer 9

when bones match the impedance of the air into the fluid

creates small movement with high force

Question 10

what is crucial for preventing hearing damage ?

Answer 10

stapedius reflex

Question 11

explain the stapedius reflex ?

Answer 11

occurs during loud sound and speech

two muscle act on the ossicles

this causes the stapes to pull away from the oval window

which causes reduced transmission of vibrational energy to cochlea

Question 12

what are the 3 chambers (scalae) of the cochlea - inner ear ?

Answer 12

inner - vestibuli

middle - media

outer - tympani

Question 13

what separates the chambers of scalae?

and what does it do?

Answer 13

basilar membrane

movement of fluid causes the membrane to move

this activates the hair cells from movement in the tectorial membrane caused by basilar membrane movement

Question 14

what is located between the scalae chambers, basilar membrane and reissners membrane ?

Answer 14

organ of corti

Question 15

what do auditory hair cells detect?

Answer 15

physical movement through sound

Question 16

what type of system is used to exaggerate sound in hair cells?

Answer 16

positive feedback

Question 17

what is the role of outer hair cells ?

Answer 17

amplification

Question 18

what causes hair cell inhibition?

Answer 18

stereocilia

Question 19

what cause hair cell activation?

Answer 19

kinocilium

Question 20

what is the pitch place theory ?

Answer 20

the helicotrema is a circular structure
- the further in the tighter the hole is

resonant frequency gets higher the further along

diff parts of basilar membrane is activated at diff frequencies

wider end - basilar membrane responds to high frequencies

tighter end - basilar membrane responds best to low frequency

Question 21

what is used to see how much people can hear and how?

Answer 21

audiograms

sound activates areas like cochlea nerve and auditory cortex

Question 22

explain wernicke’s area

Answer 22

located left temporal lobe

understanding speech

aphasia - speaking nonsense words

Question 23

explain broca’s area

Answer 23

frontal lobe

producing speech

aphasia- can’t produce words/ speak

Question 24

what is sound localisation?

Answer 24

distance and bearing and elevation of sound

Question 25

what are key elements of sound that help judge distance ?

Answer 25

high frequency travel poorly

expectations

relative attenuation - gradual reduction in sound waves

echoes

Question 26

what are key elements of sound that help judge direction?

Answer 26

inter-aural timing/phase differences

intramural volume differences

spectral colouring

Question 27

what is inter-aural volume/time delays ?

Answer 27

head is a sound shadow so sound may reach one ear before the other

the delay can tell you the direction of where the person is depending on the size

Question 28

how is the superior olive in the brain stem linked to hearing ?

Answer 28

each neuron travelling to the olive splits into 5 diff neurons

these are coincidence detectors

if hits 1+5 there’s a time difference

if hits 3+3 the sound is close by

Question 29

what is a smaller sized head good at detecting ?

Answer 29

high frequency sounds

smaller time differences between both ears aids localisation

Question 30

what is the cone of confusion?

Answer 30

sounds from opposite sides of the circle have same volume and time difference

sound from behind can sound infront

Question 31

in animals what is high frequency calls for ?

Answer 31

avoiding localisation

no sharp onsets

Question 32

in animals what is low frequency calls for ?

Answer 32

longer more intense and broad sounds attract attention

Question 33

what is average auditory reaction time ?

Answer 33

140-160ms