Physiology of Hearing and Balance

Question 1

what hearing level on an audiogram is considered normal?

Answer 1

0-20HL

Question 2

what hearing level on an audiogram is considered mild hearing loss?

Answer 2

20-40HL

Question 3

what hearing level on an audiogram is considered moderate hearing loss?

Answer 3

40-60HL

Question 4

what hearing level on an audiogram is considered severe hearing loss?

Answer 4

50-90HL

Question 5

what is the worst level of hearing loss experienced?

Answer 5

profound

Question 6

what colours of line in an audiogram represents the right and left ears

Answer 6

red- right

blue-left

Question 7

why is the TM:OW ratio so large?

Answer 7

allows more movement (this needs to be large because the inner ear is fluid/dense)

Question 8

what muscles open the eustachian tube?

Answer 8

tensor veli palatini

levator palatine

Question 9

what happens to the pressure of the middle ear if the eustachian tube is dysfunctional?

Answer 9

get negative pressure

Question 10

how many openings are there in the otic capsule and what are they called?

Answer 10

2
oval window
round window

Question 11

ear condition caused by negative pressure in the ear?

Answer 11

glue ear

Question 12

what frequency (high/low) is heard at:
apex
opening of the ear

Answer 12

apex = low
opening  = high

Question 13

what happens to a sound wave after it hits the OW?

Answer 13

goes via the scala tympani

Question 14

how do the semicircular canals control balance?

Answer 14

depending on which way the perilymph moves there will be an nerve signal sent to the brain to indicate which way the head has just turned

Question 15

what movement does the posterior semicircular canal detect?

Answer 15

movement from side to side eg ear to shoulder

Question 16

what movement does the superior semicircular canal detect?

Answer 16

moving forward and back eg nodding

Question 17

what movement does the lateral semicircular canal detect?

Answer 17

movement from side to side in a no motion

Question 18

what creates the ionic gradient in the cochlea to allow nerve signals?

Answer 18

the difference in concentration of fluid in the different compartments

Question 19

how do hair cells create an electric impulse?

Answer 19

the bending motion they do causes mechanical energy to become electrical energy

Question 20

name the locations in the central pathway to the primary auditory complex

Answer 20

cranial nerve Eight
cochlear nucleus
superior Olivary complex
Lateral lemniscus
Inferior colliculus

Question 21

what creates the nerve impulse in the cochlea?

Answer 21

wave from OW passes through the cochlea stimulating the basilar membrane; organ of corti depolarises and fires stimulating CN8

Question 22

what is the organ of corti?

Answer 22

receptor organ for hearing; contains the hair cells and is located in the cochlea

Question 23

cause of oscillopsia?

Answer 23

no vestibular input

Question 24

how can the cardiovascular system affect balance?

Answer 24

blood pressure

Question 25

name the 5 vestibular organs?

Answer 25

lateral, posterior and superior semicircular canals utricle saccule

Question 26

what 2 structures are classed as the "otolith organs"?

Answer 26

utricle | saccule

Question 27

small calcium carbonate crystals deposited in the otolith organs?

Answer 27

otoconia

Question 28

what kind of response is given by the right and left semicircular canals when the head moves to the left?

Answer 28

``` L = excitation response R = inhibition response ```

Question 29

what is nystagmus?

Answer 29

uncontrolled vestibuloochlear reflex