Vestibular System (2)

Question 1

What is vertigo?

Answer 1

Loss of orientation

Question 2

Does vertigo occur with the eyes opened and closed?

Answer 2

Yes

Question 3

What is damaged that causes someone to have oscillopsia?

Answer 3

Vestibular-ocular reflex

Question 4

What does a lesion to the oculomotor system result in?

Answer 4

Oscillopsia

Diplopia

Nystagmus

Question 5

What happens to postural control when there is a lesion?

Answer 5

Lack of stabilization (ataxia)

Question 6

What can a lesion to the cerebellum lead to?

Answer 6

Supression of the VOR reflex

Question 7

How does sound get transmitted to the labyrinth?

Answer 7

External auditory meatus

Tympanic membrane

Malleus, incus, stapes (sound amplification)

Oval window

Fluid movement in cochlea

Hair cells send signals to cochlear nerve

Pressure dissipated at round window

Question 8

What causes sound dampening in the ear?

Answer 8

Tensor tympani (malleus)

Stapedius (stapes)

Question 9

What is the labyrinth made up of?

Answer 9

Cochlea

Vestibule

Semi circular canals

Question 10

What sends signals to the vestibular portion of CN 8?

Answer 10

Bending of hair cells in semi circular canals

Question 11

What does the bony labyrinth contain?

Answer 11

Perilymph and suspends membranous labyrinth

Question 12

What makes up the membranous labyrinth?

Answer 12

Cochlear duct

Utricle

Saccule

Semi circular canals

Question 13

What is the membranous labyrinth filled with?

Answer 13

Endolymph

Question 14

How many semi circular canals are there?

Answer 14

3 (anterior, lateral, posterior)

Question 15

What do receptors in the semi circular canal detect?

Answer 15

Motion movement of Endolymph (only rotational acceleration)

Question 16

What is the cristae ampullaris?

Answer 16

Epithelium at the end of the semi circular canal

Question 17

What does movement of the cupula cause?

Answer 17

Hair cells to move and detect movement

Question 18

What do hair cells consist of?

Answer 18

Sensory neuron, multiple small stereocilia, and a single large kinocilium

Question 19

What does movement of hair cells towards the kinocilium result in?

Answer 19

Excitation

Question 20

How does the cupula move?

Answer 20

Opposite way of the head

Question 21

What do hair cells do when the head is stationary?

Answer 21

Baseline rate of firing

Question 22

What do hair cells do when the head moves?

Answer 22

Cupula bends and moves hair cells

Question 23

How do hair cells fire at a constant rate during constant movement?

Answer 23

Endolymph moves at the same speed

Question 24

What plane is the utricle in?

Answer 24

Horizontal

Question 25

What plane is the saccule in?

Answer 25

Vertical

Question 26

Where are otolith organs located?

Answer 26

Cochlea and semi circular canals

Question 27

What do otolith organs respond to?

Answer 27

Head position relative to gravity

Linear acceleration (not rotation)

Question 28

What are macula?

Answer 28

Hair cells in gelatinous membrane with calcium carbonate crystals on top

Question 29

What tilts the macula?

Answer 29

Changes in head position

Question 30

What does bending of hairs in the macula stimulate?

Answer 30

Neuronal firing frequency in CN 8

Question 31

What is the max response to the utricle?

Answer 31

Head upright and bending forward

Question 32

What is the max response to the saccule?

Answer 32

Going from side lying to standing