physiology of hearing and balance

Question 1

what are the 3 chambers of the cochlea?

Answer 1

scala vestibuli
scala tympani
scala media

Question 2

in terms of sound stimulation what does the external ear do?

Answer 2

collect sound

Question 3

in terms of sound stimulation what does the middle ear do?

Answer 3

mechanical force amplifier

Question 4

in terms of sound stimulation what does the inner ear do?

Answer 4

sound transducer/analyser

Question 5

when waves pass thriugh the cochlea what specific area of the basal membrane is stimulated?

Answer 5

organ of corti

Question 6

what does the organ of corti move against to stimulate nerve impulses?

Answer 6

tectoral membrane

Question 7

when a wave stimulates organ of corti what does it do?

Answer 7

depolarises and fires APs
stimulates CN VIII (8) then central pathways q

Question 8

where does the activity from stimulus reach its highest point?

Answer 8

superior temporal gyrus

Question 9

in terms of sound stimulation what do the inner hair cells do?

Answer 9

receive and pass sound up the auditory nerve

Question 10

in terms of sound stimulation what do the outer hair cells do?

Answer 10

transfer info to brain

Question 11

where is head positive (linear movement) sensed?

Answer 11

inside semicircular canals

Question 12

what type of movement does utricle sense?

Answer 12

horizontal

Question 13

what type of movement does saccule sense?

Answer 13

verticle

Question 14

what inside the semi-circular canals senses head movement?

Answer 14

utricle and saccule

Question 15

where are semi-circular canals located?

Answer 15

base of ampullla

Question 16

what hair-cell containing structure in the ampulla responds to rotational movement?

Answer 16

crista ampullaris

Question 17

what do hair cells in the vestibular apparatus detect movement via?

Answer 17

endolymph

Question 18

what do nerve fibres of the vestibulo-ocular reflex converge to form?

Answer 18

vestibular branch of vestibulocochlear nerve (CN VIII/8)

Question 19

what is the first step in the process of hearing?

Answer 19

vibration stimulates ossicular chain of middle ear - transmits energy to the cochlea

Question 20

what is the second step in the process of hearing?

Answer 20

inner ear receives the mechanical signals from the middle ear and converts them into electrical signals

Question 21

in stage two of hearing process how does the vibrations received by the inner ear eventually result in the stimulation of CN VIII and central pathways?

Answer 21

footplate of stapes vibrates in oval window of cochlea

vibration creates pressure waves in perilymph of cochlea

wave motion transmitted to endolymph inside cochlear duct

basilar membrane vibrates - hair cells at organ of corti move against tectoral membrane -> depolarisation = stimulation

Question 22

what is the third step in the process of hearing?

Answer 22

electrical signals culminate in Brodman areas 41/42 of the primary auditory cortex within superior temporal gyrus

Question 23

what happens in stage four in the process of hearing?

Answer 23

pressure waves in cochlear descent and become vibrations again, are dampened at the round window

Question 24

at what week in utero can the foetus hear?

Answer 24

18

Question 25

at what week in utero can the foetus respond to sound/voice?

Answer 25

26

Question 26

at 3 months what is the normal development in terms of speech for a child?

Answer 26

cooing recognising mothers voice

Question 27

at 6 months what is the normal development in terms of speech for a child?

Answer 27

babbling turns to sound and eyes towards sound happy and sad sounds

Question 28

at 12 months what is the normal development in terms of speech for a child?

Answer 28

make simple noises mama/dada follow instructions turns to sound

Question 29

from 12-24 months what is the normal development in terms of speech for a child?

Answer 29

syllable deletion syllable simplification single words

Question 30

at 18 months what is the normal development in terms of speech for a child?

Answer 30

few words colours, animal sounds, recognise body parts, simple commands

Question 31

at 24 months what is the normal development in terms of speech for a child?

Answer 31

two word phrases 50+ words understand questions and follow comman ds

Question 32

at 24-36 months what is the normal development in terms of speech for a child?

Answer 32

use 3 word sentances aware of rhyme start with adjectives understand order positioning

Question 33

what is the sense organ that is contained in the saccule and utricle?

Answer 33

macula

Question 34

what is the vestibulo-ocular reflex?

Answer 34

vestibular system working with visual system to keep objects in focus when head is moving

Question 35

what is nystagmus?

Answer 35

involuntary eye movement

Question 36

what does the vestibulospinal tract provide?

Answer 36

motor output to neck, back and leg muscles = posture

Question 37

what does the medial longitudinal fasciculus and ocular muscles provide?

Answer 37

motor output to eyes = gaze stabilisation