1b// Vestibular System

Question 1

What is the role of vestibular organ?

Answer 1

capture low frequency motion (movements)

Question 2

What is the role of the hearing organ?

Answer 2

capture high frequency motion (sound)

Question 3

what are the cellular origins of the hearing and vestibular organs?

Answer 3

Question 4

What are the inputs for a vestibular system?

Answer 4

movement and gravity

Question 5

how are movement of gravity (inputs) for the vestibular system detected?

Answer 5

mechanical sensors
(canals and otoliths)

Question 6

What happens to the input to mechanical sensors of the vestibular system?

Answer 6

the CNS integrates this info and generates responses

Question 7

What are the outputs of the vestibular system?

Answer 7

the outputs are perception and reflexes that maintain posture and gaze

ocular reflex
postural control

Question 8

Describe the whole process (input and output) of the vestibular system?

Answer 8

Question 9

Label.

Answer 9

Question 10

Where are the utricle and saccule located? And what are they joined by?

Answer 10

in the vestibule and are joined by a conduit
the saccule is also joined to the cochlea

Question 11

How many semicircular canals are there on each ear?

Answer 11

3 each
ant, post and lateral

Question 12

What do the semicircular canals have on their side? And what arte they filled with?

Answer 12

an ampulla on one side, and they are connected to the utricle
filled w/fuid and respond to movement

Question 13

What are the otolith organs and where are they located?

Answer 13

Utricle and saccule are the otolith organs. Their cells are located on the maculae, placed horizontally in the utricle and vertically in the saccule

Question 14

Label.

Answer 14

Question 15

What do maculae contain? (3)

Answer 15

The maculae contain the hair cells, a gelatinous matrix and the otoliths on top. These otoliths are carbonate crystals that help the deflection of the hairs.

Question 16

What is otolith movement?

Answer 16

linear acceleration and tilt

Question 17

What type of movement does the utricule have?

Answer 17

horizontal movement

Question 18

What type of movement does the saccule have?

Answer 18

vertical movement

Question 19

Where are the hair cells in the canals located?

Answer 19

in the ampulla

Question 20

Label.

Answer 20

Question 21

What are the orientation of the canals in the head?

Answer 21

defines 3 planes
anterior
posterior
horizontal

anterior and post canals form a 90 degree angle

lateral canals are horizontal to the other canals

therefore they work in pairs
- 6 total canals both ears

Question 22

What is the biggest cilium in vestibular hair cells called?

Answer 22

kinocilium

Question 23

What do cilia allow? And what does head movement generate?

Answer 23

Cilia allows the cells to depolarise the cell with movement of the endolymph generated by head movement

towards the kinocilium= dfepolarisation

Question 24

What type of potential do hair cells have? And what does that have?

Answer 24

Hair cells have a resting potential which has a basal discharge to the nerve

Question 25

What happens when hairs move towards or away the kinocilium?

Answer 25

Hairs moving towards the kinocilium generates depolarization and an increase in nerve discharge. Hairs moving away from the kinocilium generates hyperpolarization and a reduction in nerve discharge.

Question 26

Where do primary afferents end?

Answer 26

in vestibular nuclei in the brainstem (pons)

Question 27

Label.

Answer 27

Question 28

What are the functions of the vestibular system?

Answer 28

to detect and inform about head movements balance to keep images fixed in the retina during head movements

Question 29

What are the vestibular reflexes?

Answer 29

Vestibulo-ocular Reflex (VOR) Vestibulo Spinal Reflex (VSR)

Question 30

What is the vestibulo-occular reflex for?

Answer 30

Keeps images fixed in the retina

Question 31

Describe the mechanism of the vestibulo-occular reflex?

Answer 31

Connection between vestibular nuclei and the oculomotor and (abducen) nuclei (CN3&6) Eye movement in opposite direction to head movement, but same velocity and amplitude

Question 32

How can you categorise vestibular disorders?

Answer 32

timing and laterality acute AND unilateral slow AND unilateral or any bilateral loss

Question 33

What are the main complaints of acute and unilateral? and why?

Answer 33

imbalance, dizziness, vértigo and nausea due to sudden asymmetry

Question 34

What are the main complaints of slow and unilateral or bilateral loss?

Answer 34

imbalance and nausea – NO vertigo

Question 35

What are the 2 types of location vestibular disorders?>

Answer 35

peripheral and central

Question 36

Where are peripheral vestibular disorders located?

Answer 36

vestibular organ and/ or VIII nerve

Question 37

What are examples of peripheral vestibular disorders?

Answer 37

Vestibular neuritis Benign Paroxysmal Positional Vertigo (BPPV) Meniere’s disease

Question 38

Where are central vestibular disorders located?

Answer 38

CNS (brainstem/ cerebellum)

Question 39

What are examples of central vestibular disorders?

Answer 39

Stroke Multiple Sclerosis Tumours

Question 40

What is the clinical approach of a vestibular disorder? main diagnoses and core exam

Answer 40

*BPPV normal gelatinous matrix dislodges, so assymetrical signalling bc the crystals are moving

Question 41

What are the red flags of vestibular disorders?

Answer 41

Headache Gait problems Hyper-acute onset (vascular event) Hearing loss (e.g., blood supply to cochlea gone) Prolonged symptoms (>4 days)

Question 42

What are the balance disorders timing classification?

Answer 42

acute recurrent intermittent progressive

Question 43

What test do you do for acute balance disorders?

Answer 43

HINTS exam

Question 44

What test do you do for intermittent balance disorders?

Answer 44

Dix-Hallpike test

Question 45

What are examples of acute timing balance disorders?

Answer 45

Vestibular Neuritis Stroke

Question 46

What are examples of intermittent timing balance disorders?

Answer 46

Benign Paroxysmal Positional Vertigo (BPPV)

Question 47

What are examples of recurrent timing balance disorders?

Answer 47

Migraine (Meniere’s Disease)

Question 48

What are examples of progressive timing balance disorders?

Answer 48

Schwannoma vestibular (VIIIth nerve) Degenerative conditions (MS)

Question 49

What does more dizziness most likely mean?

Answer 49

Benign Paroxysmal Positional Vertigo (BPPV)

Question 50

What is significant about migranes?

Answer 50

any movement makes it worse

Question 51

What is the HINTS exam?

Answer 51

Question 52

What is nystagmus?

Answer 52

rhythmical, repetitive and involuntary movement of the eyes aka jerking movement of the eyes

Question 53

What could support a diagnosis of Benign Paroxysmal Positional Vertigo (BPPV)?

Answer 53

The sudden and intermittent vertigo crisis which is very characteristic of this disorder. Short lasting (minutes) spinning vertigo. Triggered when getting up and lying down. He does not refer to any symptoms when standing still He does not mention any new hearing symptom accompanying the vestibular event, the hearing problems are clearly coming from previous time.