Hearing & Balance pt.2 (II)

Question 1

where is the A1 located

Answer 1

• on superior temporal lobe

- within sylvian fissure

Question 2

where do pure tones activate?

Answer 2

temporal lobe

Question 3

ventral stream

Answer 3

• temporal lobe
• pitch, volume, tone
• receives info from 1 ear (contralateral projection from brain stem)

Question 4

wernicke’s area

Answer 4

• speech sound information
• language and comprehension
• cerebral hemisphere (junction between temporal and parietal lobe)

Question 5

wernicke’s aphasia

Answer 5

• damage to wernicke’s

- can’t understand what people are saying

Question 6

why do songs get stuck in your head

Answer 6

• cortical volume of heschl’s gyrus is smaller in people who are prone to earworms
• frontal lobe inhibition centers are physically smaller in these people

Question 7

hearing loss

Answer 7

• reduced capacity to interpret sound

Question 8

deafness

Answer 8

• profound inability to hear

Question 9

what are the 3 main causes of hearing loss and deafness

Answer 9

1. conduction deafness
2. sensorineural deafness
3. central deafness

Question 10

conduction deafness

Answer 10

• disorders of the outer ear or middle ear that prevent sounds from reaching the cochlea

Question 11

sensorineural deafness

Answer 11

• originates from cochlear or auditory nerve lesions

Question 12

central deafness

Answer 12

• caused by brain lesions such as stroke

Question 13

teflon prosthetics

Answer 13

• for fused ossicles (can be genetic)

Question 14

cochlear implants

Answer 14

• deafness due to hair cell loss

- electrical currents stimulate the auditory nerve

Question 15

hearing aids

Answer 15

• electronic amplification to deliver louder sounds to the impaired (but still functional) auditory system

Question 16

motion sick and car sick

Answer 16

faulty vestibular system

Question 17

functions of vestibular system

Answer 17

1. detects position and movement of the head

2. generates compensatory movements/body position adjustments to maintain posture

Question 18

vestibular labyrinth

Answer 18

• located in inner ear
  next to cochlea
• vestibular system

Question 19

semicircular canals

Answer 19

• vestibular system

- 3 fluid filled tubes in different planes

Question 20

otolith organs

Answer 20

• vestibular system

- fluid filled sac that responds to movement

Question 21

nodding up and down

Answer 21

semicircular canals

Question 22

tilting left and right

Answer 22

semicircular canals

Question 23

shaking side to side

Answer 23

semicircular canals

Question 24

what does movement of head do in relation to semicircular canals

Answer 24

• pushes endolymph through canals to the ampulla

Question 25

ampulla

Answer 25

• located at the end of each canal

- contains hair cells surrounded by cupula (gelatinous) coating

Question 26

what does endolymph moving/bending result in?

Answer 26

distors cupula (cilia of hair cells) similar to the auditory system

1. opens K+ ion channels
2. depolarization opens Ca2+ channels
3. glutamate released into synapse with CN8 (vestibulocochlear)

Question 27

motion sickness

Answer 27

• mismatch between vestibular and visual inputs

Question 28

role for area postrema

Answer 28

• brain believes you must be hallucinating

- triggers vomiting

Question 29

cerebellum

Answer 29

• vestibular pathways: balance and gait control (helping you move around)
  aka motor correction

Question 30

midbrain (tectum)

Answer 30

• vestibular pathways: eye movements

Question 31

spinal cord

Answer 31

• vestibular pathways: (vestibulospinal tract) postural and balance movements

Question 32

function of otolith organs

Answer 32

• inner ear, detect forward and backward movement

- horizontal and vertical acceleration

Question 33

utricle

Answer 33

• otolith organ

- for horizontal movement

Question 34

saccule

Answer 34

• otolith organ

- for vertical movement

Question 35

otoconia

Answer 35

tiny calcium carbonate crystals

Question 36

how does the otoconia affect when the head changes position

Answer 36

added weight from the otoconia produces drag on the hair cells when it changes

Question 37

when the head changes position what happens

Answer 37

1. opening of K+ channels depolarizes hair cell

2. results in Ca2+ influx and glutamate release into vestibulocochlear nerve