vestibular

Question 1

which are the mechanical sensors of the vestibular system

Answer 1

canals and otoliths

Question 2

what are the mechanical forces that canals and otoliths respond to

Answer 2

movement and gravity (input info)

Question 3

what are the responses/ outputs generated form these mechanical sensory inputs in the vestibular system?

Answer 3

ocular reflex (maintaining gaze)
postural control

(reflexes)

Question 4

where is the input info integrated to generate the reflex responces

Answer 4

in CNS

Question 5

how many semi circular cannals does a person have

Answer 5

3 pairs/ 3 each ear/ 6 total

Question 6

what are the names of each canal? (explain which name is for which direction thinking of yes and no movement and the “odd one out”)

Answer 6

anterior semicircular canal: yes
posterior: no
lateral : the other movement

Question 7

what is found on one end of each canal

Answer 7

ampula that links to utricle

Question 9

List the components of the vestibular organ

Answer 9

Semi circular canals (and ampulas at the end)
Vestibule: saccule and utricle (centre)

Question 10

What are the physical connections between canals, saccule, utricule and cochlea

Answer 10

Ampulas of canals connected to utricle

Utricle and saccule are joined by a conduit

Saccule joined to cochlea

(think sketch linear with cannals starting, then utricle then sacule then (cochlea (isnt vestibular organ but links to sacule)

Question 11

Which are the otolith organs?

Answer 11

Utricle and saccule

Question 12

On what structure do the hair cells sit on in otoliths?

Answer 12

On the maculae

Question 13

How are the hair cells/ maculae placed in space in the saccule and utricle?

Answer 13

Horizontally in utricle and verticaly in saccule

Question 14

List the layers of structures in the maculae of otoliths from deep to out

Answer 14

Hair cells
Gelatinous matrix
Otolith (helps hair deflection)

Question 15

Where are the hair cells in the canals located?

Answer 15

In ampula, the rest of the canal is filled with endolymph

Question 16

Explain ampula structure

Answer 16

-ampullary crista: hair cells are on there
- cupula in centre helps hair cell movement

Question 17

What is endolymph rich in?

Answer 17

Potassium

Question 18

State which canals are horizontal and which vertical (in relation to eachoter)

Answer 18

Anterior and posterior vertical
Lateral is horizontal

(Think of the face as the main wall- horizontla plane- the others are vertical to this)

Question 19

The canals of which ear depolarize when you move head to right

Answer 19

Right

Question 20

Vestibular system functions 3

Answer 20

Detect and inform about head movements

Keep images fixed in the retina during head movements

Balance

Question 21

What are the vestibular reflexes?

Answer 21

Vestibulospinal reflex

Vestibulooccular reflec

Question 22

Where do the eyes move when head moves to right? (Vestibulooccular refelx) how fast and how much do they move?

Answer 22

Left, equal velocity and amplitude as head movement

Question 23

What is the role of the occulomotor reflex

Answer 23

Keep images fixed in retina

Question 24

What neurological connection makes the vestibulooccular reflex possible?

Answer 24

Cestibular nuclei link with oculomotor nuclei

Question 25

What is the largest cilium called?

Answer 25

Kinocilium

Question 26

When were not moving what is the potential of hair cells?

Answer 26

Resting potential: basal discharge to nerve

Question 27

Movement towards or away from kinocilium is depol

Answer 27

Towards, increases nerve discharge and depol

Question 28

what happens when cilia move away from kinocilium

Answer 28

Hairs moving away from the kinocilium generates hyperpolarization and a reduction in nerve discharge.

Question 29

where do primary afferents in the vestibular nerve end?

Answer 29

in the brainstem (pons)

Question 30

Vestibular disorders – 2 factors that help categorise them in relation to symptoms and the possible presentations based on these factors

Answer 30

laterality and timing: acute AND unilateral chronic AND unilateral or any bilateral loss

Question 31

presentation of acute and unilateral

Answer 31

vertigo, dizziness, imbalance and nausea

Question 32

presentation of slow and uni or bilateral

Answer 32

imbalance and nausea (DEF NOT VERTIGO)

Question 33

Balance disorders: state the two possible areas of pathology

Answer 33

1) peripheral vestibular disorders: vestibular organ or CN 7 2) central vestibular disorders: CNS (brainstem/ cerebellum)

Question 34

which are the common peripheral vestibular disorders?

Answer 34

vestibular neuritis benign paroxysmal positional vertigo (BPPV- crystals thing) Meniere's disease

Question 35

what are the central vestibular disorders

Answer 35

stroke (cerebellar) multiple sclerosis tumours

Question 36

what are the most common vestibular diagnoses in general?

Answer 36

BPPV Vestibular Neuritis Vestibular Migraine Stroke (cerebellar)

Question 37

what body parts does the core exam for vestibular disorder involve?

Answer 37

eyes ears legs

Question 38

what are some red flags relevant to vestibular disorders?

Answer 38

symptom related: headache gait problems hearing loss timing related: hyper acute onset prolonged symptoms (>4days)

Question 39

what is the altering cover test?

Answer 39

covering one eye and observibgn the other, abnormal movement is up down

Question 40

which disorders are acute?

Answer 40

vestibular neuritis stroke

Question 41

which disorders are intermittent?

Answer 41

benign paroxysmal positional vertigo (BPPV)

Question 42

WHICH DISORDERS are recurrent

Answer 42

Migraine (Meniere’s Disease)

Question 43

which disorders are progressive

Answer 43

Schwannoma vestibular (VIIIth nerve) Degenerative conditions (MS)

Question 44

what is reccurent and what is intermittent?

Answer 44

reccurent: regular pattern, something happens again anad again intermittent meaning it comes on repeatedly but with no regular pattern

Question 45

what presentation do doctors do hints exam for?

Answer 45

acute dizziness

Question 46

what does HINTS exam involve?

Answer 46

**Head-Impulse** Test  abnormal for Vestibular Neuritis less likely to have this with stroke how you do it: Horizontal rotational VOR: (vestibulooccular reflex) (Meaning you move rapiudly patients head to one side of the "No" nod) normal is if eyes stay fixed to centre, abnormal is if they follow **Nystagmus** (eyes just drift to one direction) Vestibular organ Vs Cerebellar/brainstem nystagmus **Test-of-Skew** Deviation Vertical  misalignment - usually absent in peripheral pathology (alternating cover test, you repeatedly cover one then other eye and look for VERTICAL- UP DOWN eye movements= abnormal!!)

Question 47

when is Dix- Hallpike tets done?

Answer 47

to diagnose Intermittent vestibular disorders