Vestibulo cochlear system. Audition and balance

Question 1

What are the orientations of the 3 semicircular canals?

Answer 1

Lateral, posterior and superior

Question 2

What is immediately below the middle ear?

Answer 2

Bulb of the internal jugular vein

Question 3

What does the Eustachian tube connect?

Answer 3

Nasopharynx and middle ear

Question 4

What is the order of the ossicles from lateral to medial?

Answer 4

Malleus, incus, stapes

Question 5

How does the stapes connect to the cochlea?

Answer 5

Oval window

Question 6

Which nerve innervates the outer surface of the tympanic membrane?

Answer 6

V3 division of trigeminal nerve.

Question 7

Where can pain of the tympanic membrane refer to?

Answer 7

Jaw

Question 8

Why is otitis media more common in infants?

Answer 8

The eustachean tube is more hosizontal => harder for bacteria in middle ear to drain => easier for bacteria in nasopharynx to migrate to middle ear

Question 9

How are the ossicles joined?

Answer 9

With synovial joints

Question 10

What are the 2 muscles in the middle ear that regulate movement of the ossicles?

Answer 10

Tensor tympani and stapedius

Question 11

Which nerve innervates tensor tympani?

Answer 11

Trigeminal

Question 12

Which nerve innervates stapedius

Answer 12

Seventh

Question 13

Which branch of CN7 runs through the middle ear?

Answer 13

Chorda tympani

Question 14

The bony labyrinth of the inner ear is contained within which bone?

Answer 14

Petrous temporal bone

Question 15

Which fluid fills the bony labyrinth of the inner ear?

Answer 15

Perilymph

Question 16

What do we call the swelling of each of the semicircular canals of the vestibular apparatus?

Answer 16

Ampulla

Question 17

What are the 2 components that are within the vestibule of the inner ear?

Answer 17

Saccule and utricle

Question 18

What do the saccule and utricle sense?

Answer 18

Static equilibrium (ie orientation of head in space)

Question 19

What do the semicircular canals sense?

Answer 19

Dynamic equilibrium (ie movement of the head in space)

Question 20

Which fluid is within the semicircular canals of the inner ear?

Answer 20

Endolymph

Question 21

Which chamber of the cochlea is the middle one?

Answer 21

Scala media

Question 22

What joins the scala vestibuli and the scala tympani

Answer 22

The helicotrema

Question 23

Which fluid is contained in the scala media?

Answer 23

Endolymph

Question 24

What is unique about endolymph as an extracellular fluid?

Answer 24

It is rich in potassium

Question 25

What do the stereocilia of inner and outer hairs cells of the organ of Corti sit in?

Answer 25

Tectorial membrane

Question 26

What is the function of inner hair cells of the organ of Corti?

Answer 26

Conduct afferent auditory signal to brainstem

Question 27

What is the function of outer hair cells of the organ of Corti?

Answer 27

Amplify movements of the basilar membrane

Question 28

What is the auditory pathway?

Answer 28

Inner hair cells => bipolar cell => cochlear nuclei => (decussate and ipsilateral) => superior olivary complex => (lateral lemniscus) => inferior colliculus => MGN => A1

Question 29

What pathway is from the superior olivary complex to the MGN?

Answer 29

Lateral lemniscus

Question 30

What is the function of the superior olivary complex?

Answer 30

Uses interaural discrepanicies in timing and intensity to localise stimuli in the horizontal plane

Question 31

Which end of the basilar membrane is wider?

Answer 31

The apex