HEARING

Question 1

what are the 2 theories of language development?

Answer 1

Poverty of stimulus theory (based on Chomsky’s Nativist theory)

Empiricist theory

Question 2

what is neural plasticity?

Answer 2

the inherent ability of the auditory system to reorganise its functioning an early age

Question 3

how is neural plasticity related to age? How is this important in the context of hearing loss?

Answer 3

If congenital hearing loss is corrected by the age of 3, recovery is possible. Much after this, the functionality hearing capabilities will be lost forever

Question 4

which lemniscus (lateral or medial) does the auditory pathway run through?

Answer 4

LATERAL lemniscus

Question 5

what is unique about the organisation of the primary auditory cortex?

Answer 5

tonotopically arranged, meaning it is ordered in terms of frequency recognition

Question 6

what is the innervation of the levator veli palatini?

Answer 6

pharyngeal branch of vagus nerve

Question 7

what is the innervation of the tensor veli palatini?

Answer 7

mandibular branch of trigeminal

Question 8

where is perilymph found?

Answer 8

bony labyrinth

Question 9

where is endolymph found?

Answer 9

membranous labyrinth

Question 10

scala tympani and scala vestibuli are ducts within which cochlear structure?

Answer 10

bony labyrinth

Question 11

which cochlear duct does the stapes bone communicate with at the oval window?

Answer 11

Scala vestibuli

Question 12

what is the name of the membrane that seperates the scala vestibuli and scala media?

Answer 12

vestibular membrane

Question 13

what is the name of the membrane that seperates the scala media and scala tympani?

Answer 13

basillar membrane

Question 14

what is the function of the tectorial membrane?

Answer 14

provides a surface upon which K+ rich endolymph runs over hair cells in response to sound frequencies

Question 15

what is the absolute hearing range of humans?

Answer 15

20-20000Hz

Question 16

what is the sensitive hearing range of humans?

Answer 16

1500-4000Hz

Question 17

short / high frequency waves are absorbed in which part of the cochlear duct?

Answer 17

Base of cochlear

Question 18

low / low frequency waves are absorbed in which part of the cochlear duct?

Answer 18

apex/helicotrema

Question 19

what is the function of inner hair cells?

Answer 19

5-10% of all hair cells

important in conveying sound into action potentials

Question 20

what is the function of outer hair cells?

Answer 20

90-95% of all hair cells

involved in sound modulation in response to sensory input

Question 21

where is the organ of corti located?

Answer 21

scala media of cochlear duct

Question 22

the scala vestibuli and scala tympani belong to which cochlear labyrinth?

Answer 22

Bony labyrinth

Question 23

how is sound transmitted through bone (as opposed to air)?

Answer 23

bone conduction vibrates skull against cochlear, which in turn vibrates basillar membrane of scala media

Question 24

what are deiters cells?

Answer 24

supporting cells that separate and support the IHC and OHC

Question 25

what is the tectorial membrane?

Answer 25

membrane overlying the IHC of scala media

Question 26

tip-link proteins open K+ channels on stereocilia of IHC, what occurs after this?

Answer 26

K+ influx and IHC depolarisation Ca2+ influx Glutamate release type I spiral ganglion neurone excitation

Question 27

how do outer hair cells modulate sound

Answer 27

cause hair cell elongation in response to efferent stimulation More space between tectorial membrane and stereocilia means less endolymph flow

Question 28

what are the two main components of the vestibular system?

Answer 28

vestibule (containing otholitic organs) | semicircular canals

Question 29

what is the function of the vestibule?

Answer 29

detects linear changes in direction (eg. accelleration)

Question 30

the utricle detects ......... changes in accelleration

Answer 30

horizontal

Question 31

the saccule detects ......... changes in accelleration

Answer 31

vertical

Question 32

what is the function of macullae?

Answer 32

receptor cells that convey information from hair cells of utricle/saccule to the vestibular nerve

Question 33

what is the otoconia analogous to in the cochlear?

Answer 33

tectorial membrane

Question 34

what type of movement do the semicircular canals sense?

Answer 34

dynamic and angular movement

Question 35

what is the crista ampullaris?

Answer 35

sensory organ of rotation, found in the ampulla of each of the semicircular canals cone shaped structure containing hair cells that are moved by the cupulla in response to angular changes in accelleration

Question 36

describe the vestibo-ocular reflex

Answer 36

detects angular movement to either side and contracts extraocular muscles to move the other way

Question 37

what ganglion is associated with the vestibo-ocular relfex?

Answer 37

scarpa's ganglion

Question 38

what is nystagmus?

Answer 38

involuntary eye movement that occurs when semicircular canals are being stimulated when the head is not in motion

Question 39

what descending motor tract receives input from the vestibular nuclei in order to control core muscle tone?

Answer 39

vestibulo-spinal

Question 40

what is the diagnostic significance of outer hair cells?

Answer 40

they are motile, releasing otoacoustic emissions which can be measured in a hearing loss diagnostic test

Question 41

what physical property of the basillar membrane allows it to absorb different frequencies?

Answer 41

Tighter @ cochlear base, meaning higher frequencies absorbed here

Question 42

what is pure tone audiometry?

Answer 42

hearing levels (in Db) on y axis and frequency on x axis tests bone and air conduction at different frequencies

Question 43

what are otoacoustic emmsions tests? how can they be interpreted?

Answer 43

measurement of low intensity signals released by outer hair cells of inner ear. OAE normal - conductive hearing loss OAE reduced significantly - cochlear deafness OAE normal/slightly low - auditory pathway neuropathy

Question 44

what is tympanometry?

Answer 44

used to test mobility of tympanic membrane and auditory ossicles

Question 45

how is conductive hearing loss recognised on a pure tone audiogram?

Answer 45

when a net difference of 10Db or more is seen between bone and air conduction

Question 46

how is sensorineural loss recognised on a pure tone audiogram?

Answer 46

when there is a marked reduction in bone and air conduction at certain frequencies

Question 47

how is mixed hearing loss identified on a pure tone audiogram?

Answer 47

no pattern