Hearing

Question 1

what is the pathway sound must travel by to reach the oval window?

Answer 1

Tympanic Membrane - Malleus - Incus - Stapes - Oval Wndow

Question 2

What is the ratio Tympanic Membrane : Oval Window

Answer 2

the first is 20x bigger thus there is an amplification of the wave

Question 3

What are the subdivisions of the cochlea?

Answer 3

Scala Vestibuli
Scala Media
Scala Tympani

Question 4

Where is the basilar membrane found?

Answer 4

between the scala media and scala tympani

Question 5

What is tonotopia?

Answer 5

the coding of different information by the basilar membrane depending on the frequency of the sound

Question 6

What area of the basilar membrane codes for higher frequencies?

Answer 6

the stiffer part: the base (close to the oval window)

Question 7

What area of the basilar membrane codes for lower frequencies?

Answer 7

the less stiff part: the apex (away from oval window)

Question 8

what type of cells code for sound and where are they found?

Answer 8

Hair Cells

on the basilar membrane

Question 9

what is at the top of the hair cells?

Answer 9

Stereocillia

Question 10

What type of hair cells can be damaged by aspirin or gentomycin or other ototoxic compunds? and what is the result of the damage?

Answer 10

Outer hair cells

Loss of hearing

Question 11

Where does the efferent signal for the outer hair cells come from?

Answer 11

Superior Olivary Complex

Question 12

What do inner hair cells do?

Answer 12

Sound coding

Question 13

What are the stereocillia of the outer hair cells attaching to?

Answer 13

the tectorial membrane

Question 14

What is the function of the outer hair cells?

Answer 14

increase movement of the basilar membrane when low intensity waves reach the cochlea
depolarisation causes contraction

Question 15

What type of channels sit at the top of the inner hair cells? how are they activated?

Answer 15

K+ channels

Mechanically Activated

Question 16

What is the Kinocillium?

Answer 16

tallest sterocillia at the top of the inner hair cell

Question 17

Movement towards the Kinocillium causes 1

Movement away from the Kinocillium causes 2

Answer 17

1 Depolarisation (Always bigger)
2 Hyperpolarisation

Question 18

activation of the inner hair cells causes the release of the neurotransmitter….

Answer 18

Glutamate

Question 19

Which scala is filled with high [k+]

Answer 19

scala media

Question 20

How is K recycled for activation of the inner hair cells?

Answer 20

thanks to K channels between the scala media and the scala tympani

Question 21

what is the middle ear’s function?

Answer 21

impedance matching, without it all the sound would just bounce back

Question 22

Where does the information of the auditory pathway is integrated?

Answer 22

Superior Olivary Complex

Question 23

Where is the cell body of the CN8?

Answer 23

Spiral Ganglion within the chochlea

Question 24

The nerve cells of CN8 are bipolar T/F

Answer 24

T

Question 25

The information that reaches each Superior Olivary Complex comes from one ear only

Answer 25

F, information comes from both

Question 26

Where is the nucleus of CN8?

Answer 26

Pons

Question 27

in which lobe is the auditory cortex?

Answer 27

Temporal Lobe

Question 28

Information from the Superior Olivary Complex travels via

Answer 28

the lateral lemniscus

Question 29

what midbrain structure connects the lateral lemniscus of the pons with the Medial Geniculate Nucleus of the thalamus

Answer 29

the inferior colliculus

Question 30

What is the Medial Geniculate Nucleus (MGN) related to

Answer 30

Hearing

Question 31

in the cortex of the brain is there asymmetrical representation of complex sounds? if so how it it divided?

Answer 31

Speech-> left | Music -> Right

Question 32

the auditory cortex is tonotropic (T/F) and receives information from one ear only (T/F)

Answer 32

T | F

Question 33

What is the pathway for sound signalling?

Answer 33

Inner Hair Cells - CN8 (Spiral Ganglion) - Chochlear Nuclei - Superior Olive (x2) - Lateral Lemniscus - Inferior Colliculus - Medial Geniculate Nucleus - Auditory Cortex

Question 34

At what site do we determine where is sound coming from?

Answer 34

Superior Olivary Complex

Question 35

The medial superior olive localises time depending on... (1)... and this is the most relevant form for ----2--

Answer 35

1 Time Delay | 2 Low frequencies

Question 36

Time Delay analysis of sound depends on

Answer 36

more neurons are activated by the ear where the sound is closer to

Question 37

Localising sound by intensity differences happens in

Answer 37

Lateral Superior Olive and Medial Nucleus of Trapezius Body

Question 38

Localising sound by intensity differences is more relevant for

Answer 38

Higher Frequencies

Question 39

What is the process of Localising sound by intensity differences

Answer 39

1 one nuclei gets activated more than the other 2 lateral superior olive sends excitatory signal to ipsilateral Medial Nucleus of Trapezius Body which then sends inhibitory signal to contralateral lateral superior olive 3 Both lateral superior olives send signals to the higher centres but one is going to be stronger than the other due to more inhibition from Medial Nucleus of Trapezius Body