vestibular Flashcards

1
Q

which are the mechanical sensors of the vestibular system

A

canals and otoliths

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2
Q

what are the mechanical forces that canals and otoliths respond to

A

movement and gravity (input info)

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3
Q

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

A

ocular reflex (maintaining gaze)
postural control

(reflexes)

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4
Q

where is the input info integrated to generate the reflex responces

A

in CNS

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5
Q

how many semi circular cannals does a person have

A

3 pairs/ 3 each ear/ 6 total

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6
Q

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”)

A

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

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7
Q

what is found on one end of each canal

A

ampula that links to utricle

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8
Q
A
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9
Q

List the components of the vestibular organ

A

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

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10
Q

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

A

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)

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11
Q

Which are the otolith organs?

A

Utricle and saccule

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12
Q

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

A

On the maculae

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13
Q

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

A

Horizontally in utricle and verticaly in saccule

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14
Q

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

A

Hair cells
Gelatinous matrix
Otolith (helps hair deflection)

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15
Q

Where are the hair cells in the canals located?

A

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

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16
Q

Explain ampula structure

A

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

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17
Q

What is endolymph rich in?

A

Potassium

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18
Q

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

A

Anterior and posterior vertical
Lateral is horizontal

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

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19
Q

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

A

Right

20
Q

Vestibular system functions 3

A

Detect and inform about head movements

Keep images fixed in the retina during head movements

Balance

21
Q

What are the vestibular reflexes?

A

Vestibulospinal reflex

Vestibulooccular reflec

22
Q

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

A

Left, equal velocity and amplitude as head movement

23
Q

What is the role of the occulomotor reflex

A

Keep images fixed in retina

24
Q

What neurological connection makes the vestibulooccular reflex possible?

A

Cestibular nuclei link with oculomotor nuclei

25
Q

What is the largest cilium called?

A

Kinocilium

26
Q

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

A

Resting potential: basal discharge to nerve

27
Q

Movement towards or away from kinocilium is depol

A

Towards, increases nerve discharge and depol

28
Q

what happens when cilia move away from kinocilium

A

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

29
Q

where do primary afferents in the vestibular nerve end?

A

in the brainstem (pons)

30
Q

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

A

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

31
Q

presentation of acute and unilateral

A

vertigo, dizziness, imbalance and nausea

32
Q

presentation of slow and uni or bilateral

A

imbalance and nausea

(DEF NOT VERTIGO)

33
Q

Balance disorders: state the two possible areas of pathology

A

1) peripheral vestibular disorders: vestibular organ or CN 7

2) central vestibular disorders: CNS (brainstem/ cerebellum)

34
Q

which are the common peripheral vestibular disorders?

A

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

35
Q

what are the central vestibular disorders

A

stroke (cerebellar)
multiple sclerosis
tumours

36
Q

what are the most common vestibular diagnoses in general?

A

BPPV
Vestibular Neuritis
Vestibular Migraine
Stroke (cerebellar)

37
Q

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

A

eyes
ears
legs

38
Q

what are some red flags relevant to vestibular disorders?

A

symptom related:
headache
gait problems
hearing loss

timing related:
hyper acute onset
prolonged symptoms (>4days)

39
Q

what is the altering cover test?

A

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

40
Q

which disorders are acute?

A

vestibular neuritis
stroke

41
Q

which disorders are intermittent?

A

benign paroxysmal
positional vertigo (BPPV)

42
Q

WHICH DISORDERS are recurrent

A

Migraine
(Meniere’s Disease)

43
Q

which disorders are progressive

A

Schwannoma vestibular (VIIIth nerve)
Degenerative conditions (MS)

44
Q

what is reccurent and what is intermittent?

A

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

45
Q

what presentation do doctors do hints exam for?

A

acute dizziness

46
Q

what does HINTS exam involve?

A

Head-ImpulseTest
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-SkewDeviation
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!!)

47
Q

when is Dix- Hallpike tets done?

A

to diagnose Intermittent vestibular disorders