Vestibular System

Question 1

What are the 3 main inputs of the vestibular system?

Answer 1

Visual
Proprioceptive
Vestibular info

Question 2

What are the main outputs of the vestibular system?

Answer 2

Reflexes that allow you to be maintain stable posture, gaze and stop you from falling over

Question 3

Where is the vestibular organ found?

Answer 3

Posterior area of inner ear

Question 4

What does the vestibular organ do?

Answer 4

Senses rotation and movement of the head

Question 5

How many semicircular canals are there and describe them

Answer 5

There are 3: anterior, posterior and lateral

They have am ampulla on one side and are connected to the utricle

Question 6

What is the biggest cilium on vestibular hair cells called?

Answer 6

Kinocilium

Question 7

Where are hair cells in the vestibular cells found?

Answer 7

All 5 organs

Question 8

How do the cilia on hair cells allow depolarisation?

Answer 8

They are moved by endolymph when the head moves

Question 9

What are the otolith organs?

Answer 9

Utricle and saccule

Question 10

What are otolith?

Answer 10

Crystals on top of the hair cells that help them move

Question 11

How are cells placed in the utricle?

Answer 11

Horizontally

Question 12

How are cells placed in the saccule?

Answer 12

Vertically

Question 13

What ion is endolymph rich in?

Answer 13

Potassium

Question 14

In the semicircular canals where is the hair located?

Answer 14

On the crista in the ampulla

Question 15

What are the 3 planes in the semicircular canals?

Answer 15

Anterior and posterior (that form a 90 degree angle)

Lateral which are horizontal to the others

Question 16

Where do primary afferents end?

Answer 16

Vestibular nuclei and cerebellum

Question 17

What do the vestibular nuclei have projections to?

Answer 17

Spinal cord
Nuclei of the extraocular muscles (eye movements)
Cerebellum (to get feedback)
Centres for cardiovascular + respiratory control

Question 18

What is the role of the vestibular cortex?

Answer 18

To detect and inform about head movements
To keep images fixed in the retina during head movements
Postural control

Question 19

Where is the vestibular cortex found?

Answer 19

Many cortical areas participate

Question 20

How many potentials do hair cells have?

Answer 20

Resting
Excitation
Inhibition

Question 21

Describe the resting potential of hair cells

Answer 21

Has a basal discharge to the nerve

Question 22

What happens to nerve discharge during excitation?

Answer 22

Increases

Question 23

When do hairs move towards to kinocilium?

Answer 23

During excitation

Question 24

When do hairs move away from the kinocilium

Answer 24

During inhibition

Question 25

What type of movement do otolith organs detect?

Answer 25

Acceleration without angle

Question 26

Out of the utricle and saccule, which is sensitive to horizontal movement and which to vertical movement?

Answer 26

Utricle: horizontal movement Saccule: vertical movement

Question 27

What movement do semicircular canals detect?

Answer 27

Angular acceleration

Question 28

How do semicircular canals work?

Answer 28

In pairs- anterior from one side will work with posterior from other side Cupulla moves and displaces hair cells

Question 29

What does the vesticulo ocular reflex do?

Answer 29

Keeps images fixed in the retina when you move your head

Question 30

What does the vestibulo spinal reflex do?

Answer 30

If moving and about to loose balance it stops you from falling by causing certain muscles to contract

Question 31

Where do motor neurons of the lateral vs medial tract go to in terms of the vestibulospinal reflex?

Answer 31

``` Lateral= go to limb muscles Medial= go to neck and back muscles ```

Question 32

What assessed in a vestibular system assessment?

Answer 32

``` Anamnesis Posture and gait Cerebellar function Eye movements Vestibular tests ```

Question 33

What is the main symptom of balance disorder?

Answer 33

Dizziness or vertigo

Question 34

What do peripheral vestibular disorders affect?

Answer 34

Labyrinth or CN VIII

Question 35

What do central vestibular disorders affect?

Answer 35

Brainstem or cerebellum

Question 36

What are the main acute vestibular disorders?

Answer 36

Vestibular Neuritis (‘labyrinthitis’), stroke

Question 37

What is the main intermittent vestibular disorder?

Answer 37

Benign Paroxysmal Positional Vertigo (BPPV)

Question 38

What are the main recurrent vestibular disorders?

Answer 38

Meniere’s Disease (hearing loss will be in one ear), Migraine

Question 39

What are the main recurrent progressive disorders?

Answer 39

Schwannoma vestibular (VIIIth nerve), Degenerative conditions (MS)

Question 40

What else may dizziness indicate other than vestibular disorders?

Answer 40

``` Heart disorders Presyncopal episodes Orthostatic hypotension Anaemia Hypoglycaemia Psychological Gait disorders ```

Question 41

How is hearing loss characteristic in Menieres?

Answer 41

Only occurs in one ear