6: Physiology of hearing and balance Flashcards Preview

ENT Week 1 2017/18 > 6: Physiology of hearing and balance > Flashcards

Flashcards in 6: Physiology of hearing and balance Deck (30)
Loading flashcards...
1

Audiogram used to determine hearing loss:

20dB - 40dB mild

41 - 70 moderate

71 - 95 severe

95+ profound

2

The outer ear is a ___ for sound.

The middle ear is an ___ for sound.

The inner ear is a ___ for sound.

receiver

amplifier

converter

3

Which tube connects the middle ear and the nasopharynx and equalises the pressure of the ears?

Eustachian tube

4

What are the two openings found in the cochlea?

Oval window

Round window

5

A pressure wave transmitted through the ___ window by the stapes causes ___ cells to depolarise.

oval window

hair cells

6

If vibrations were to be passed straight from the air to the cochlea, 99% of it would be reflected due to the impedance of the liquid.

What structures overcome this?

What is this process called?

Auditory ossicles (malleus, incus, stapes)

Impedance matching

7

Which fluid does pressure waves travel through?

Perilymph

8

What frequency of sound is hear at the cupula of the cochlea?

What frequency is heard in the modiolus (spirals)?

Low

High

9

Which spaces are found above and below the scala media?

What fluid do they both contain?

Scala vestibuli above

Scala tympani below

Both contain perilymph

10

___ of the cilia by pressure waves causes ___ channels to open and the hair cells to depolarise.

Bending

Na+

11

What space sits between the scala vestibuli and the scala tympani?

What organ does it contain?

What fluid does it contain?

Scala media

Organ of Corti

Endolymph

12

Which organ contains hair cells and is found in the scala media?

Organ of Corti

13

Is the endolymph high or low in sodium?

Why?

Low

to allow action potentials to travel through it

14

The inner hair cells are involved in (hearing / balance).

hearing

15

(Repolarisation / depolarisation) occurs when stereocilia are deflected towards the longest fibres.

Depolarisation

16

(Repolarisation / depolarisation) occurs when the stereocilia are deflected away from the longest fibres.

Repolarisation

17

Which part of the brain processes sound?

Temporal lobe

(primary auditory cortex)

18

What are the vestibular end organs of the inner ear?

Anterior, lateral and posterior semicircular canals

Urticle

Saccule

19

What hair cells do the urticle and saccule contain?

When are they depolarised?

Stereocilia

On movement

20

What is otoconia?

Calcium carbonate crystals found in the urticle and saccule

Help stimulate stereocilia supposedly

21

The otolith organs allow the brain to detect linear motion.

What directions do the

a) urticle

b) saccule

help with?

a) Horizontal motion

b) Vertical motion

22

At what angle are the semicircular canals oriented away from one another?

90 degrees

23

Cilia ___ or ___ depending on which way they are deflected.

depolarise

hyperpolarise

24

The organs of balance on one side of the head are (stimulated / inhibited) when you turn towards that side.

stimulated

25

The organs of balance on one side of the head are (stimulated / inhibited) when you turn away from that side.

inhibited

26

What symptom does pathology of the organs of balance cause?

Vertigo

sensation of spinning

27

What is nystagmus?

Abnormal movement of eyes in people with vertigo - damage to balance centres, sensation of turning, vestibulo-ocular reflex

28

What is the vestibulo-ocular reflex?

Eyes remain fixed on object while you turn your head

29

With NO vestibular input, what symptom do you get?

Oscillopsia

feels like your eyes are jumping around in your head

30

Which antibiotic can cause total vestibular input loss causing oscillopsia?

Gentamicin