15a. Inner Ear, Hearing and Vestibular Function Flashcards Preview

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Flashcards in 15a. Inner Ear, Hearing and Vestibular Function Deck (49)
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1

What is the name of the eardrum?

Tympanic membrane

2

What is connected to the tympanic membrane?

Malleus

3

Name the auditory ossicles

Malleus
Incus
Stapes

4

What is the stapes connected to?

Oval window

5

What does the eustachian tube connect the middle ear to?

Nasopharynx

6

What are the functions of the eustachian tube?

Equalise pressure
Drain fluid from the middle ear into the throat

7

What is impedance?

Resistance to movement

8

How is impedance combatted in the ear?

Energy from the large surface area of the tympanic membrane is concentrated onto the oval window
Lever action of the ossicles amplifies vibration

9

What comprises the vestibular apparatus?

Utricle
Saccule
3 semi-circular canals

10

What information is received by the vestibular apparatus?

Balance
Co-ordination
Head positions

11

What lobe does information from the vestibular apparatus go to?

Temporal

12

What is mechanotransduction?

Sound waves are converted to nerve impulses by the displacement of fluid

13

What does pushing in of the oval window cause?

Movement of fluid in the scala vestibuli

14

What fluid is found in the scala vestibuli?

Perilymph

15

What cochlear labyrinth is connected to the round window?

Scala tympani

16

What fluid is found in the scala media/ cochlear duct?

Endolymph

17

What is contained in the scala media?

Organ of Corti

18

What separates the scala vestibuli from the scala media?

Reissner's membrane

19

Which membrane separates the scala media from the scala tympani?

Basilar membrane

20

What is the composition of perilymph?

Similar to CSF
High Na+
Low K+

21

What is the composition of endolymph?

Low Na+
High K+

22

What is found in the lateral wall of the cochlea?

Stria vascularis

23

What makes up the stria vascularis?

Capillaries and marginal cells

24

What is the function of marginal cells?

Maintain the resting potential of endolymph by maintaining high K+

25

What membrane lies above the hair cells of the Organ of Corti?

Tectorial membrane

26

What happens when hair cells in the Organ of Corti are bent against the tectorial membrane?

Cilia bend
Influx of K+
Depolarisation causes opening of voltage gated Ca++ channels
Glutamate is released

27

What does amplitude of a sound wave correspond to?

Volume

28

What is the normal hearing threshold?

0-90dB

29

What volume causes pain?

130dB

30

What does frequency of a sound wave correspond to?

Pitch