Hearing and balance

Question 1

Semilunar canals are on all 3 planes why?

Answer 1

All hair cell movement are picked up

Question 2

What is the function of utricle and saccule?

Answer 2

Starting and stopping movements of hair cells to keep balance

Question 3

Pressure waves cause vibrations where?

Answer 3

Basilar membrane vibrates which causes tectorial membrane to move hair cells which opens mechanically gates ion channels to cause AP

Question 4

How does sound waves cause basilar membrane to vibrate?

Answer 4

Stapes vibrates against the oval window, this causes perilymph in semi-lunar canals which causes the basilar membrane to vibrate

Question 5

What is the organ of Corti?

Answer 5

Receptor organ that contains hair cells that give rise to nerve signals

Question 6

What are the inner hair cells responsible for?

Answer 6

Sensory hair cells

Question 7

What are the outer hair cells responsible for?

Answer 7

Receive efferent from superior olive and modulate sound level

Question 8

How is the AP triggered from hair cell movements?

Answer 8

Mechanically gated K+ channels open and move into the cell causing depolarisation. This causes Ca2+ ion channels to open and Ca2+ to move in and cause vesicles to fuse with membrane

Question 9

What is the auditory stream from the primary auditory cortex to the motor cortices?

Answer 9

Primary auditory cortex
Association auditory cortex
Wernickes area
Arcuate fasciulus
Brocas area
Motor cortices

Question 10

Describe the route of the auditory pathway?

Answer 10

From the dorsal and ventral cochlear nuclei.
Some fibres go to the superior olivary nucleus and then to the inferior colliculus.
Other fibres go straight to the inferior colliculus.
All fibres converge at the inferior colliculus to the medial geniculate nucleus in the thalamus. Then tot he primary auditory cortex

Question 11

What is the name of the fluid in the canals?

Answer 11

Endolymph

Question 12

How does the utricle and saccule sense movement?

Answer 12

Calcium carbonate deposits on the top of the cells move in response to gravity

Question 13

What is the vestibular nerve pathway responsible for?

Answer 13

Maintaining balance

Question 14

What is the route of the vestibular nerve pathway?

Answer 14

Semicircular canals to the vestibular nucleus then CN III and IV up the via the medial longitudinal fasiculus