1b Auditory Systems

Question 1

What does a vestibular organ capture?

Answer 1

Captures low frequency motion (movements)

Question 2

What does a hearing organ capture?

Answer 2

Captures high frequency motion (sound)

Question 3

What is meant by the frequency of a sound?

Answer 3

The number of cycles of the sound per second, perceived tone

Question 4

What is the frequency measured in?

Answer 4

Hertz

Question 5

What is the amplitude?

Answer 5

the sound pressure - therefore corresponding to loudness

Question 6

What is the human range of hearing?

Answer 6

20-20000 Hz
0-120 decibels

Question 7

What are the functions of the outer ear?

Answer 7

Capture sound and focus it onto the tympanic membrane

Modest amplification of the upper range of speech frequencies by resonance in the canal

To protect the ear from external threats

Question 8

By how much does the outer ear amplify the sound?

Answer 8

10 DB

Question 9

What is the middle ear?

Answer 9

All the structures from the tympanic membrane to the oval window

Question 10

What is the main function of the middle ear?

Answer 10

Mechanical amplification (Provides an additional 20-30DB)

Question 11

What happens to the tympanic membrane when a sound hits it?

Answer 11

It vibrates at the same frequency as the sound wave which just hit it

Question 12

What are the ossicles?

Answer 12

The three smallest bones in the body -

Malleus
Incus
Stapes

Question 13

What is the function of the cochlea?

Answer 13

function is to transduce vibration into nervous impulses

Question 14

What two things does the cochlea capture?

Answer 14

Captures the pitch and intensity of the sound

Question 15

Where does the stapes connect to the cochlea?

Answer 15

The oval window

Question 16

Where does the sound go from the oval window of the cochlea?

Answer 16

Scala Vestibuli

Question 17

What does the scala vestibuli and the scala tympani contain?

Answer 17

Perilymph

Question 18

What does the scala media contain?

Answer 18

Endolymph

Question 19

What is the perilymph high in?

Answer 19

Sodium

Question 20

What is the endolymph high in?

Answer 20

Potassium

Question 21

Where is the hearing organ or Organ of Corti Located?

Answer 21

In the basilar membrane - separates the scala media and the scala tympani

Question 22

What type of structures are the scala vestibuli and the scala tymphani?

Answer 22

Bone structures

Question 23

What type of structure is the scala media?

Answer 23

Membranous Structure

Question 24

What structure does the Organ of Corti lie in?

Answer 24

The basilar Membrane

Question 25

Which sound frequency moves the base of the basilar membrane?

Answer 25

high frequency sounds- narrow and tight

Question 26

Which sound frequency moves the apex of the basilar membrane of the cochlea?

Answer 26

Low frequency sounds- Wide and loose

Question 27

How is the basilar membrane arranged?

Answer 27

Tonotopically

Question 28

What are the two types of hair cells which the organ of corti contains?

Answer 28

Inner hair cells Outer hair cells

Question 29

What is the difference in the way the inner and outer hair cells of the organ of corti are arranged?

Answer 29

Inner = one line Outer = three lines

Question 30

What sits above the hair cells in the cochlea?

Answer 30

the tectoral membrane

Question 31

What does the tectoral membrane allow?

Answer 31

Allows hair deflection, which in turn depolarises the cell

Question 32

Inner hair cells carry which type of signal?

Answer 32

Afferent signals

Question 33

Which nerve do the inner hair cells pass information to?

Answer 33

Auditory nerve

Question 34

What is the function of the inner hair cells?

Answer 34

Transduction of the sound into nerve impulses

Question 35

What do the outer hair cells do?

Answer 35

Carry efferents from the auditory nerve

Question 36

What is the function of the Outer Hair cells?

Answer 36

Modulate the sensitivity of the response

Question 37

What are the hairs of the hair cells called?

Answer 37

Stereocilium

Question 38

What is the longest cilium called?

Answer 38

Kinocilium

Question 39

What does deflection of the stereocilium towards the longest cilium cause?

Answer 39

Opening of K+ Channels

Question 40

What happens inside the hair cell when the stereocilium are deflected towards the tallest one?

Answer 40

K+ Channels open, Causes depolarisation Opens Ca2+ channels leads to the release of an excitatory neurotransmitter (Glutamate) and therefore the simulation of the afferent nerve

Question 41

How does louder sounds affect the sterocilium?

Answer 41

Louder sounds deflect the kinocilium more

Question 42

What causes the movement of the sterocilium?

Answer 42

The sheer force of the tectoral membrane over the top of the sterocilium will move them

Question 43

What happens when the cells are hyper-polarised?

Answer 43

K+ channels are closed

Question 44

What happens to the nerves from the spiral ganglion?

Answer 44

Via the vesticulo-cochlear nerve, they travel to the ipsilateral cochlear nuclei in the pons

Question 45

Which cranial nuclei come into the pons?

Answer 45

5,6,7,8

Question 46

Where is the cochlear nuclei?

Answer 46

In the pons

Question 47

Where does the auditory system nerve decussate?

Answer 47

In the brain stem - in the pons, at the superior olive level

Question 48

What area of the thalamus is related to hearing?

Answer 48

Medial geniculate body

Question 49

Where is the auditory cortex?

Answer 49

The temporal lobe

Question 50

After what point are the auditory connections bilateral?

Answer 50

After the superior olive level

Question 51

What are the three types of hearing loss?

Answer 51

Conductive Sensorineural Mixed

Question 52

What is conductive hearing loss?

Answer 52

Problem is located in the outer / middle ear

Question 53

What is sensorineural hearing loss?

Answer 53

Damage to the sensory organ (cochlear) or the nerve (auditory nerve)

Question 54

What is central hearing loss?

Answer 54

originates in the brain and the brainstem

Question 55

What is the time frame for sudden hearing loss?

Answer 55

Minutes to days

Question 56

What is the time frame for progressive hearing loss?

Answer 56

Months to years

Question 57

What is cerumen impaction?

Answer 57

Wax in the ear

Question 58

What is otisis

Answer 58

inflammation of the middle ear- bubbles can be seen through the ear drum, suggesting there is liquid inside

Question 59

What is otosclerosis?

Answer 59

When you get breakdown of the middle ear bones

Question 60

What are the causes of sensorineural hearing loss?

Answer 60

Inner ear - noise, presbycusis, ototoxicity Nerve - acoustic neuroma (CN VIII tunour)

Question 61

What is presbycusis?

Answer 61

Deterioration of the hair cells due to old age

Question 62

What is ototoxicity?

Answer 62

Chemotherapy causes inner ear nerve damage And Antibiotics - Gentomycin = aminoglycosides

Question 63

What is a vestibular schwaanoma?

Answer 63

A unilateral tumour which causes damage to the nerve resulting in sensorineural hearing loss

Question 64

What does a tuning fork do?

Answer 64

Two tests to assess the presence of gross hearing

Question 65

what are the two tests done with a tuning fork called?

Answer 65

Weber test Rinne test

Question 66

What is the webber test?

Answer 66

Tuning fork placed on top of the head - sound should be heard in the middle

Question 67

What is the Rinne test?

Answer 67

tuning fork placed behind the ear then moved to air

Question 68

If Rinne test is louder than webber, what does this suggest?

Answer 68

That your problem is an outer ear / conductive problem

Question 69

What pattern on a audiogram would be seen in conductive hearing loss?

Answer 69

Difference between Bone and air conduction

Question 70

What pattern on a audiogram would be seen in sensorineural hearing loss?

Answer 70

Same conduction between air and bone

Question 71

What are the four treatments of hearing loss?

Answer 71

Fix underlying cause hearing Aids Cochlear Implants Brainstem Implants

Question 72

What sounds are made by the outer hair cells as they expand and contract?

Answer 72

Otoacoustic emissions (OAEs)- low intensity sounds * often part of newborn hearing screening and hearing loss monitoring