Physiology Of Hearing

Question 1

Travelling speed of sounds?

Answer 1

340m/s

Question 2

What is intensity measured in?

Answer 2

dB SPL

Question 3

What is pain threshold?

Answer 3

140db spl

Question 4

Frequency range for adult humans?

Answer 4

20 to 20,000

Question 5

Over which level can you get permanent hearing damage?

Answer 5

Over 90 db

Question 6

What are 3 bones inside middle ear cavity?

Answer 6

Incus, malleus, stapes

Question 7

How much pressure is increased in middle ear?

Answer 7

X45

Question 8

Otitis media?

Answer 8

Infection/ inflammation of middle ear, in children (upper respiratory tract infection), fills with fluid

Question 9

Grommets?

Answer 9

Small tube placed in ear for drainage

Question 10

Otosclerosis?

Answer 10

Fusion of stapes and oval window

Question 11

Frequency at basal end?

Answer 11

High

Question 12

Frequency apical end?

Answer 12

Low

Question 13

Scala vestibule is connected to?

Answer 13

Oval window

Question 14

Scala tympani is connected to?

Answer 14

Round window

Question 15

Where do scala vestibule and tympani communicate?

Answer 15

Helicotrema at apex of cochlear

Question 16

What do scala vestibule and tympani contain?

Answer 16

Perilymph high sodium low potassium

Question 17

What does scala media contain?

Answer 17

Endolymph

Question 18

Where is endolymph produced?

Answer 18

Stria vascularis

Question 19

What does round window act as?

Answer 19

Pressure relief, bulges out so fluid doesn’t get compressed

Question 20

What does organ of corti do?

Answer 20

Detects sound induced motions of basilar membrane

Question 21

Hair cells are between?

Answer 21

Tectorial and basilar membrane

Question 22

Apical membrane of hair cells is in?

Answer 22

Endolymph

Question 23

Basolateral membrane is bathed in?

Answer 23

Perilymph

Question 24

How many hair cells in human cochlea?

Answer 24

15,000

Question 25

What causes mechano-electrical transducer channels to open?

Answer 25

Tips links pulls open in direction of excitation

Question 26

When outer hair cells depolarise and hyperpolarise what happens?

Answer 26

Depolarise-shorten Hyperpolarise-lengthen Prestin in basolateral membrane, OHC motor, a modified anion exchanger

Question 27

Inner hair cells are innervated by?

Answer 27

10-20 type 1 spinal neurons

Question 28

Outer hair cells are innervated by?

Answer 28

Type 2 spinal neurons, painfully loud sound

Question 29

Efferent fibres from medial olive innervated?

Answer 29

Outer hair cells

Question 30

Efferent fibres from lateral olive synapse on?

Answer 30

Type 1 afferent fibres

Question 31

Cochlear ganglion transmits afferent information via which nerve?

Answer 31

8th

Question 32

Noise can cause what?

Answer 32

Glutamate excitotoxicity Mitochondrial damage Physical effects of hair bundle

Question 33

How many people over 70 have significant hearing loss?

Answer 33

30%

Question 34

Ototxic drugs?

Answer 34

CispLatin, loop diuretics,aminoglycoside antibiotics salicylate

Question 35

Genetic mutation?

Answer 35

1 in 2000

Question 36

How many deafness genes?

Answer 36

More than 50

Question 37

Which genes are affected in congenital deafness?

Answer 37

50% in gap junction genes

Question 38

Maximum channels in cochlear implants?

Answer 38

24

Question 39

Central auditory system?

Answer 39

Can’t stop needing info, must proceed ``` Cochlear nucleus Superior Olivary complex Nucleus of lateral leminiscus Inferior colliculus Medial geniculate body Primary auditory cortex ```

Question 40

What does superior olivary complex do?

Answer 40

Localise sound in space

Question 41

Interaural level difference?

Answer 41

Sound intensity in lateral superior olive

Question 42

Interaural time difference?

Answer 42

Medial superior olive- timing of arrival of sounds in left and right ears

Question 43

Inferior colliculus?

Answer 43

Laminar organisation, isofrequency sheets. Combine complex frequency and amplitude analysis of dorsal cochlear nucleus and sound localisation from superior olivary nucleus Reflex centre

Question 44

Lesions in auditory cortex cause?

Answer 44

Sound localisation, discrimination of temporal pattern, intelligibility of speech

Question 45

What are the targets of deafness genes in the cochlea?

Answer 45

``` Tight junctions Transduction complex Gap junctions Afferent synapse Tectorial membrane Stria vascularis ```

Question 46

What is motor aphasia?

Answer 46

Brocas

Question 47

What is sensory aphasia?

Answer 47

Wernickes