Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Year 2 Neuro > Vestibular Systems > Flashcards

Vestibular Systems Flashcards

1
Q

What are the three main inputs of the vestibular system?

A

Visual

Proprioceptive (pressure)

Vestibular (organ related from inner ear) Rotation and gravity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are the main outputs of the vestibular system?

A

Mainly reflexes

  • Ocular reflex (allows stable gaze)
  • Postrural control

Needs to be fast

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the role of the CNS in the vestibular system?

A

The CNS integrates this information (inputs and outputs) and generates the responses.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Where is the vestibular organ?

A

inner ear

inner ear contains hair cells for hearing and balance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What comprises the vestibule?

A

Utricule and Saccule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the main features of the vestibular canals?

A

There are three semicircular canals on each ear, anterior, posterior and lateral

The semicircular canals have an ampulla on one side, and they are connected to the utricle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do the canals sit in the skull?

A

Anterior and posterior canal form a 90 degree angle

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the purpose of locating the vestibular organs?

A

The location of the vestibular organ draws planes for anterior and posterior canals

These planes determine which structure will be stimulated with a specific head movement.

Important to generate the right responses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the features of the vestibular hair cells?

A

have a kinocilium (the biggest cilium) and stereocilia

Specially designed to move with the movement of fluid (endolymph)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the function of the cilia?

A

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

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the otolith organs?

A

Utricle

Saccule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the main features of the otolith organs?

A

Their cells are located on the maculae, placed horizontally in the utricle and vertically in the saccule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What do the maculae contain?

A

The maculae contain the hair cells, a gelatinous matrix and the otoliths on top.

These otholiths are carbonate crystals that help the deflection of the hairs.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Where are the hair cells of the canals?

A

The hair cells in the canals are located in the ampulla. The rest of the canal only has a liquid high in potassium called endolymph

NO OTHOLITS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the main features of the ampulla?

A

The ampulla has the crista, where the hair cells are located. The cells are surrounded by the cupula which helps the hair cell movement

Cupula closes the ampulla so that the endolmyph can move the cupula to different sides helping the deflection of the cilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the semi-circular canal planes

A

The orientation of the canals in the head defines three planes. Anterior and posterior canals form a 90° angle.

Lateral canals are horizontal to the other canals.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where do the primary afferent end up?

A

Primary afferents end in vestibular nuclei and in the cerebellum

Brainstem for reflexes (need to be quick)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What do vestibular nuclei have projections to?

A

Spinal cord
Nuclei of the extraocular muscles
Cerebellum
Centres for cardiovascular + respiratory control

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Summarise the vestibular pathways

A

Hair cells (vestibular organs) recipe inputs

Info goes to vestibular cortex

Also need vestibulospinal, vestibulocerebellar and vestibulo-ocular reflexes

20
Q

What comprises the vestibular cortex?

A

Not one specific area. Since many inputs and integrators are involved, many cortical areas participate.

Main processing centre thought to be in the parietal lobe, in the Parieto-Insular Vestibular Cortex (PIVC)

21
Q

What are the vestibular system functions?

A

To detect and inform about head movements

To keep images fixed in the retina during head movements

Postural control

22
Q

How do hair cells potential work?

A

Hair cells have a resting potential which has a basal discharge to the nerve ((still need to contract muscles to stay still due to gravity)

Hairs moving towards the kinocilium generates depolarization and an increase in nerve discharge. (One ear)

Hairs moving away from the kinocilium generates hyperpolarization and a reduction in nerve discharge.
(The other ear)

23
Q

What is linear acceleration?

A

Movement in either the horizontal or vertical plane

Not at an angle

24
Q

What is responsible for otolith movement?

A

E.g. Tilt
Otolith movement
Basal discharge

25
Q

What happens during backward/forward movement?

A

Hyperpolarisation or Inhibiton so system can make compensatory movement in muscles

26
Q

What is responsible for horizontal movement?

A

Utricule

27
Q

What is responsible for vertical movement?

A

Saccule

28
Q

What do the semi-circular canals react to?

A

Angular acceleration

Cupulla moves and displaces hair cells

Will cause hyper polarisation or inhibition

The signal being sent on the vestibulocochlear nerve is velocity

29
Q

How do semi circular canals work?

A

SCC work in pairs according to the planes

  • Both laterals
  • Anterior from one side with posterior of the opposite side
30
Q

What are the two vestibular reflexes?

A

Vestibulo-ocular Reflex
(VOR)

Vestibulo Spinal Reflex
(VSR)

31
Q

What are the main features of the Vestibulo-ocular reflex (VOR)?

A

Keeps images fixed in the retina

Connection between vestibular nuclei and oculomotor nuclei

Eye movement in opposite direction to head movement, but same velocity and amplitude (compensatory movement of the eye in reaction to the head movement)

32
Q

What are the main features of the Vestibulo Spinal Reflex (VSR)?

A

Motor neurons to limb muscles (lateral tract)

Motor neurons to neck and back muscles (medial tract)

Postural control, avoidance of falls and compensatory body movement according to the head position.

33
Q

How do you assess the vestibular system?

A

Anamnesis (history)
Posture and gait
Cerebellar function
Eye movements

34
Q

What are the different vestibular test?

A

Caloric test (stimulate inner ear with diff. temperatures which should generate dizziness)

Video head impulse test (vHIT), cannot test each ear separately. better tolerated and v quick

Vestibular evoked myogenic potential (VEMP) - should see response in neck muscles

Rotational test (needs equipment, chair with torsional motor)

35
Q

What imaging can be used for the vestibular system?

A

CT Scan, MRI

36
Q

What are the main symptoms of balance disorder?

A

Dizziness or Vertigo

37
Q

Is balance disorder common?

A

Very common, 25% of ENT and neurological referrals

38
Q

How can balance disorder be categorised?

A

Can be cathegorised based on location of the affected structure and evolution of signs and symptoms.

39
Q

What must you also bear in mind when assessing vestibular issues?

A

Symptoms and impact assessment

e.g. if dancer can have profound affect on life and lead to mental health issues etc.

40
Q

What is Vertigo?

A

Perception of rotation

Feel like things are spinning

41
Q

What is dizziness?

A

Related to Vertigo but no turning

Very vague term

42
Q

Where do peripheral vestibular disorders occur?

A

labyrinth and/or VIII nerve

43
Q

Give example of peripheral disorders

A

vestibular neuritis (inflammation of vestibular nerve)

Benign Paroxysmal Positional Vertigo (BPPV) abnormal presence of crystals in canals

Meniere’s disease (affects inner ear completely hearing and balance) Increased liquid in inner ear

Unilateral and Bilateral vestibular hypofunction

44
Q

Where do central vestibular disorders occur?

A

CNS

45
Q

Give example of central disorders

A

Stroke
MS
Tumors

46
Q

How can we classify balance disorders based in evolution?

A

Acute (vestibular neuritis)

Recurrent (Meniere’s disease)

Intermittent (BPPV)

Progressive (degenerative diseases, schwannoma)

47
Q

What problems may patients present with that are not necessarily vestibular?

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

Year 2 Neuro (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions