Brainscape's Knowledge GenomeTM

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


See full index

.. > Vestibular System > Flashcards

Vestibular System Flashcards

1
Q

What is the function of the vestibular system?

A

Essential in producing motor responses; necessary for daily funciton

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

What are the 5 components of the vestibular system?

A 
Peripheral receptor apparatus
Central vestibular nuclei
Vestibulo-ocular network
Vestibulo-spinal network
Vestibulo-thalamic cortical network
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Where is the peripheral receptor apparatus?

What is the function of it?

A

Inner ear

Transduces head motion/position

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

Where is the central vestibular nuclei?

What is their function?

A

Brainstem

Integrates and distributes info that controls motor activities and spatial orientation

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

Where is the vestibule-ocular network?

What is its function?

A

Vestibular nuclei

Controls eye movements

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

What is the function of the vestibulo-spinal network?

A

Coordinated head movements, axial musculature, and postural reflexes

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

What it’s he function of the vestibule-thalamic cortical network?

A

Conscious perception of movement/spatial orientation

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

What the the vestibular receptor organs?

A

Semicircular canals

Otoliths organs (utricle and saccule)

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

What kind of movement does semicircular canal detect?

A

Rotational head movements

Angular accelerations

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

What kind of movement do otoliths organs detect?

A

Linear accelerations

Translation head movements

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

What are the receptors of vestibular organs innervated by?

A

Primary afferent fibers of vestibular ganglion (Scarpa ganglion)

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

Where do central porcesses vestibular ganglion enter and terminate?

A

Enter brainstem

Terminate in ipsilateral vestibular nuclei and cerebellum

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

Where is perilymph?

A

B/w membranous and bony labyrinths

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

Where is endolymph found?

A

Membranous labyrinth, bathing receptors of auditory and vestibular system

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

What maintains the ion concentrations of peri and endolymph?

A

Concentrations maintained by secretory cells in membranous labyrinth and endolymphatic sac

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

What is a vestibular disease caused by?

A

Disturbances in volume or ionic content of endolymph

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

What is the blood supply to the vestibular system?

A

Labyrinthine a. (Branch of AICA)

Stylomastoid a.

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

How does the labyrinthine a. Enter temporal bone

A

Via IAM

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

What happens if the labyrinthine a. Is compromised?

A

Compromised vestibular and cochlear funciton

Vertigo, nystagmus and/or unstable gait

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What do type 1 and 2 hair cells contain?

A

Contain 60-100 stereocilia

1 kinocilium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What innervates

Type 1 hair cells?

Type 2?

A

Cn 8 via nerve calyx

Cn 8 via boutons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What does movement of stereocilia toward kinocilium cause?

A

Depolarization and AP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What does movement of stereocilia away from kinocilium cause?

A

Hyperpolarization

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What is the ampullae?

How are the hair cells distributed in it?

A

Semicircular ducts

Hair cells in cristae across base of ampulla and extending into cupulla

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is the function of the ampulla?

A

Rotational and angular accelerations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

How do angular accelerations act on the ampulla?

A

Displace endolymph

—>

Bends cupulla

—>

Displace stereocilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What does the macula consist of?

A

Utricle and saccule

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

How are hair cells organized in the macula?

A

Hair cells’ stereocilia extends into gelatinous otoliths membrane covered by otoconia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is the function of the macula?

A

Detect gravity/linear accelerations

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

How does gravity/linear accelerations act on the macula?

A

Displace otoconia
—>
Bend underlying hair cell stereocilia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Where do the priamry afferent of the vestibular system come from and enter at?

A

Primary aff. = cn 8
From ampullae or macula
Thru scarpa ganglion
Enter at pontomedullary junction

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Where do primary afferents of the vestibular system project to?

A

Vestibular nuclei (superior, medial, later, and inferior) IPSILATERALLY

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What do the vestibular nuclei encode?

A

Direction, speed of movement, and head position

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What do the 2nd order nuerons coming from vestibular nuclei target?

A

CNs 3,4, 6 nuclei

And 
Vestibulocerebellum 
SC
RF
Thalamus
35
Q

Where do the vestibular nuclei project to?

A

Ventral posterior nuclear complex in thalamus

36
Q

Where do thalamic nuclei go to?

What are they conveying?

A

To cortical regions of S1, Parietoinsular vestibular cortex, posterior parietal cortex

Relay vestibular input needed for processing motion and body orientation

37
Q

What happens if the Parietoinsular vestibular cortex is lesioned?

A

Vertigo
Unsteadiness
Loss of visual vertical

38
Q

What happens if the posterior parietal cortex is lesioned?

A

Confusion in spatial awareness

39
Q

What are vestibulovestibular fibers?

A

Reciprocal connections b/w R and L vestibular nuclei

R side activ. —> L side inhibited

40
Q

Where are spinovestibular fibers from?

What do they provide?

A

From all SC levels

Provide proprioceptive input

41
Q

What are the vestibulocerebellar fibers?

Where do they project to ?

A

Fibers thru juxtarestiform body

Sends DIRECT projection to cerebellum

(Only sensory organ body that does this)

42
Q

What do primary vestibulocerebellar fibers target?

What kind of fibers are these?

A

Dentate nucleus of cerebellum

Mossy fibers

43
Q

What do the secondary vestibulocerebellar fibers target?

A

Flocculonodular lobe - fastigial and dentate nuclei

44
Q

What do the reciprocal cerebelli vestibular fibers provide?

A

Regulatory mechanisms for coordinating eye movements, head movements, and posture

45
Q

What nuclei does the lateral vestibulospinal tract come from?

A

Inferior and lateral nuclei

46
Q

Where does the lateral vestibulospinal tract project to?

What does it control?

A

Projects to ipsi SC at cervical and lumbosacral regions

Controls extensors for maintenance of posture

47
Q

Where does the medial vestibulospinal tract come form?

What is the input to it?

A

Medial vestibular nucleus

Integrated input from vestibular receptors, cerebellum and PCMLS

48
Q

What is the pathways of the medial vestibulospianl tract?

What is the function?

A

Medial vestibular nucleus —> MLF —> Cervical SC

Stabilize neck flexor and extensor musculature

49
Q

What reflex is the medial vestibulospianl tract needed for?

A

Critical in vestibulo-colic reflex

Stabilizes head via activation of neck musculature

50
Q

What is the Vestibulo-ocular reflex for?

A

Stabilizes images on retina during head movements thru vestibular input

51
Q

Describe the vestibulo-ocular reflex

A

Head rotates —> endolymph moment in semicircular canals —> vestibular input about head motion —> drives COUNTER ROTATION of EYES

52
Q

What is the slow phase of eyes characterized by?

A

Eyes move away from head motion

53
Q

What is the fast phase of eyes characterized by?

A

Eyes snap black toward head motion

54
Q

What is needed in order for the vestibulo=ocular reflex to occur?

A

Need activation of ocular muscle for slow phase via vestibular apparatus

55
Q

In the vestibulo ocular reflex,

What happens when you turn your head to the right?

A 
Fluid in right semicircular ducts—> activate right afferent fibers 
—> 
Right vestibular nuclei 
—> 
CN 6 
— inter-nuclear neurons via MLF —>CN 3

—> Lateral rectus, Medial rectus

56
Q

What links left lateral rectus with the right medial rectus?

A

Internuclear nuerons

Go from CN 6 —> CN 3 using MLF

57
Q

What is the Vestibulo=ocular reflex?

A

Push pull mechanisms that unifies movements of eyes thru bilateral symmetry of VOR circuits

58
Q

What will the left vestibular apparatus do when the head is rotated right?

A

Left vestibular afferents are inhibited

Cause complementary circuit to relax

(Via vestibulovestibular fibers)

59
Q

What is physiological nystagmus?

A

Combo of slow phase punctuated by fast return phase

60
Q

How do we name physiological nystagmus ?

A

For the fast phase

The direction he head is turning

61
Q

What does unilateral damage to the vestibular system cause?

A

silences output from damaged side causing steady firing of intact side by CN 8

Causes spontaneous nystagmus, vertigo, falls, and vomiting

62
Q

What will peripheral damage to vestibular labyrinth or CN 8 cause?

A

Imbalance b/w left and right vestibular input

Nystagmus

63
Q

What happens if there is central damage to the brainstem or cerebellar strucutres ?

A

Nystagmus w/ impaired voluntary saccades and/or smooth pursuit

64
Q

How do you test for nystagmus?

A

Caloric test

65
Q

In the caloric test what will warm water cause?

A

Nsytagmus that beats toward irrigated ear

I.e. fast phase is toward ear irrigated

66
Q

In the caloric test, what will cold water cause?

A

Nystagmus that beats AWAY from irrigated ear

If r. Ear done, fast phase will be toward the left

67
Q

What is Ménière’s disease caused by?

A

Disruption of normal endolymph volume causing endolymphatic hydrops (distortion of membranous labyrinth)

68
Q

What are the Sxs of Ménière’s disease?

What are the txs for Ménière’s disease?

A 
fluctuating hearing loss
Vertigo
Positional nystagmus
Nausea 
Tinnitus

Restrict salts and diuretics to reduce hydrops, implant shunt to endolymphatic sac

69
Q

What is benign paroxysmal positional vertical characterized by?

Caused by?

A

Brief episodes of vertigo that coincide w/ changes in body position

Cupololithiasis

70
Q

What is cupololiithiasis

A

Otonconia crystals lodged in cupola of semicircular changes that will change the movemnt of endolymph and cause feeling of motion when headchanges positions

71
Q

What is vestibular schwannoma (Acoustic neuroma)

A

Benign tumor from Schwann cells in vestibular root

72
Q

Where is a vestibular schwannoma?

What will it impinge on?

A

Within cerebellopontine angle

Structures traversing IAM
CN 7,8, labyrinthine a.

73
Q

What are the symptoms of Vestbiular schwannoma?

A

Hearing loss, gait difficulties, tinnitus

74
Q

What is vestibular neuritis caused by?

A

Edema of vestibular n. Or ganglion due to recent viral infection (i.e. herpes simplex)

75
Q

What are the symptoms of vestibular neuritis?

What will patients report recent history of?

Txs?

A

Severe vertigo
Nausea
Vomiting
NO HEARING LOSS THOUGH

Recent Hx of URI, Cold, or influenza

Antiemetic, vestibular suppressants, corticosteroids, and antiviral agents

76
Q

What is dizziness?

A

Non specific term for spatial disorientation

May or may not feel movement
Could have nausea or postural instability

NOT EXCL. Vestibular in origin

77
Q

What is vertigo?

A

Illusion of body motion, often spinning

78
Q

What is subjective vertigo?

A

Patient feels spinning while things in environment are not moving

79
Q

What is objective vertigo?

A

Patient not moving but has sensation of object spinning

80
Q

What is the oculocephalic reflex?

A

A head rotated back and forth will have yes that move in opposite direction

81
Q

Do you see an oculocephalic reflex in conscious patients?

A

NO

Voluntary eye movements mask reflex

82
Q

How can the oculocephalic reflex be used in comatose patients?

A

To asses brainstem function

If brainstem is intact, doll’s eye reflex is present

83
Q

What happens if there is a lesion to MLF?

A

One eye = abducted

Other one does not move

INO

(Remember that the MLF is the tract for internuclear neurons)

.. (19 decks)

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