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neuro final exam > Neuroweek 14-15 (11-14) > Flashcards

Neuroweek 14-15 (11-14) Flashcards

1
Q

The maculae and cristae are innervated by

A

Bipolarneurons of the vestibular (Scarpa’s) ganglion
The central processes of these cells form thevestibular nerve which enters the brain stem at the ponto-medullary junction

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2
Q

The primary afferent fibers of the bipolar neurons leaving both the macular and ampular epithelium have their cell bodies in

A

The vestibular (Scarpa’s) ganglion.

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3
Q

The central processes of bipolar neurons form the vestibular nerve which enters the brain stem at the

A

Pontomedullary junction just medial to the acoustic portion of the vestibulocochlear nerve (CN VIII)

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4
Q

The central nervous system component is mainly found in the 4 Vestibular Nuclei at the pontomedullary junction SLIM

A

Superior vestibular nucleus
Lateral vestibular nucleus
Inferior vestibular nucleus
Medial vestibular nucleus

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5
Q

Vestibular Nuclei have input from:

VOC

A

Vestibular nerve
Cerebellum
Other inputs

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6
Q

Vestibular Nerve Bifurcates into

A

Short ascending and long descending branches to the vestibular nuclei.

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7
Q

Afferents from the Semicircular canals go primarily to

A

Medial and superior vestibular nuclei but some go to lateral and inferior as well

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8
Q

Afferents from the Macular epithelium go primarily to

A

The lateral, medial and inferior vestibular nuclei

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9
Q

Some fibers from SSCs (ampula) rise

A

Directly thru inferior cerebellar peduncle into the cerebellum to end in the nodulus and perhaps the floccular cortex with collaterals ending in the fastigial nucleus

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10
Q

Semicircular canal afferent fibers go primarily to

A

Medial and superior vestibular nuclei

few go to the lateral and inferior nuclei.

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11
Q

Semicircular canal medial and superior nuclei are closely linked to

A

eye movements

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12
Q

the Macular inputs go primarily to the lateral, medial and inferior vestibular nuclei which are closely linked to

A

Closely linked to postural adjustments

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13
Q

Cerebellar projections to vestibular nuclei projecting to and from the Cerebellum goes through the

A

Inferior cerebellar peduncle to all vestibular nuclei. There are Inhibitory projections from cerebellar cortex of flocculonodular lobe and Excitatory projections from the fastigial nucleus.

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14
Q

Inhibitory projections from the cerebellar cortex comes from the

A

Cerebellar cortex of flocculonodular lobe

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15
Q

Excitatory projections from the cerebellar cortex comes from the

A

Fastigial nucleus.

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16
Q

Commissural Connections are found between most of the nuclei but most prominent between

A

The contralateral medial and superior nuclei.

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17
Q

Commissural connections are Primarily

A

Inhibitory - increased activity on one side inhibits activity on the other. since vestibular input is bilateral it cannot accelerate one side of head & not the other

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18
Q

When rotating to the right the right vestibular nuclei receives

A

Additional excitation by the primary afferents and the left vestibular nuclei receives less excitation

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19
Q

When the right vestibular nuclei is excited it produces

A

Inhibition of the left vestibular nuclei and less inhibition of the right vestibular nuclei by the left vestibular nuclei. therefore the vestibular primary afferents and commissural connections work together

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20
Q

Commissural Connections are Important for comparison of activities of the

A

Pairs of semicircular canals and macular structure. With the similarity of function of commissural connections to that of the primary afferent input, these commissural connections are a Mechanism by which compensation can occur for unilateral vestibular damage

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21
Q

Other Inputs to Nuclei are from

A

Spinal cord & brainstem

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22
Q

Vestibular nucleus projects to the

A

Thalamus & Cerebrum

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23
Q

Vestibular nuclear projections from vestibular nuclei to Thalamus & Cerebrum are responsible for.

A

Conscious awareness of head position and acceleration.

This is the least robust of any sensory system

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24
Q

Projections from superior, medial & lateral vestibular nuclei are to the (bilateral)

A

Ventroposterolateral (VPL) nucleus of thalamus

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25
Q

The projections from the ventroposterolateral (VPL) nucleus of thalamus are to

A

4 cortical areas related to vestibular function in insula and parietal lobe

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26
Q

Role of cerebral vestibular areas

A

Sense of body & head position but not normally cued into it as perceptual necessity. are more perceptually cued into vision and proprioception.

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27
Q

True / false- We rely on vision more, then proprioception, then vestibular

A

True

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28
Q

We rely on vision for

A

sense of movement

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29
Q

We rely on proprioception for

A

sense of position along with vision

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30
Q

There are strong connections between the vestibular nuclei and the

A

Reticular Formation.

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31
Q

Connections with UMN of reticulospinal tracts are complementary to

A

Vestibulospinal tract which controls balance & posture.

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32
Q

Connections through RF to hypothalamus controls

A

Autonomic responses to vestibular input.

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33
Q

Overstimulation of vestibular system or vestibular system damage causes

A

Nausea, vomiting, pallor and perspiration

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34
Q

Direct projection of 1° afferents and projections from most vestibular nuclei into cerebellum occurs through the

A

Inferior cerebellar peduncle.

35
Q

Vestibulocerebellar projections go primarily to flocculonodular lobe with collaterals going to the fastigial & dentate nuclei and some other areas of cortex. These connections are for

A

balance, reflexes and movement coordination

36
Q

Vestibulomotor system has lateral and medial vestibular nuclei with upper motor neurons which give rise to

A

Descending lateral and medial vestibulospinal tracts

37
Q

Lateral and medial vestibular nuclei give rise to two upper motor neuron (UMN) descending tracts

A

Lateral vestibulospinal tract (LVST)

Medial vestibulospinal tract (MVST)

38
Q

Lateral vestibulospinal tract (LVST) arises from,

A

lateral vestibular nucleus

39
Q

LVST is the Larger of the two tracts and has

A

Excitatory primarily ipsilateral effects on spinal cord extensor nuclei throughout the spinal cord.

40
Q

The biggest input to LVST is from the

A

Cerebellum, considerable inputs also come from the macular epithelium and the semicircular canals into the lateral vestibular nucleus

41
Q

Lateral vestibulospinal tract (LVST) facilitates and maintains

A

Extensor tone in limbs and trunk – antigravity response

42
Q

Medial vestibulospinal tract (MVST) Descends from

A

Medial vestibular nucleus primarily to the cervical spinal cord

43
Q

Functions of MVST are to

A

Stabilize the head in space when the body is moving/ walking around
Stabilize the eyes (& head) and maintain gaze during body movements

44
Q

Vestibular nuclei also projections to

A

Extraocular Motor Neurons.

45
Q

Medial Longitudinal Fasciculus (MLF) projections from the superior and medial vestibular nuclei project to .

A

Nuclei of CN III, IV, VI

46
Q

The MLF has a laterality pattern but effect projects

A

Bilaterally

47
Q

Vestibular projections to the extraocular lower motor neuron nuclei are important for

A

Coordination of eye movement with body movement or head movement (vestibulo-ocular reflex).

48
Q

The Vestibulo-ocular reflex functions to

A

Elicit compensatory eye movements through a network of neural connections
Stabilize eye position with movements that are equal in magnitude and opposite in direction to the head movement.
Can be suppressed at will to focus on a moving target while turning the head in the same direction

49
Q

Anatomy of the connections for the vestibulo-ocular reflex.

A

Afferent fibers from the semi-circular canals end in medial vestibular nucleus.
The Medial vestibular nucleus projects bilaterally via MLF to abducens nucleus (CN VI)
Axons from abducens nucleus (CN VI) activates lateral rectus & contralateral oculomotor nucleus (CN III).
The contralateral Oculomotor nucleus (CN III) activates the contralateral medial rectus

50
Q

What happens when the head is rotated to the left?

A

The right (contralateral) lateral rectus and left (ipsilateral) medial rectus is activated to move the eyes to the opposite direction – in this case to the right.

51
Q

Nystagmus

A

A physiological post-rotatory event with very quick full circle rotation; can occur when rotation exceeds VOR ability to provide compensation (Compensatory eye movement)- Jerky bidirectional eye movements. Two phases to this movement, Slow & quick movements in opposite directions.

52
Q

Saccade

A

Quick nystagmus- eye movement

53
Q

T / F- Nystagmus Occurs as a quick saccade in direction of rotation & slow movement in opposite direction

A

True

54
Q

Opticokinetic nystagmus

A

A physiological response Induced by looking at moving visual stimuli, such as moving vertical lines or objects. There is a Slow movement in direction of moving objects then fast saccade back.

55
Q

Two areas in the cerebral cortex where opticokinetic nystagmus is produced

A

Parieto-occipital cortex and frontal eye fields

56
Q

Slow movement produced by

A

Parieto-occipital cortex

57
Q

Quick movement back are produced by

A

Frontal eye fields.

58
Q

Pathological forms of Nystagmus occurs without fulfilling its normal function. Can be the result of damage to one or more components of

A

Vestibular system, including semicircular canals, otolith organs, and/or floculonodular lobe (vestibulocerebellum)

59
Q

How is vestibulo-ocular Reflex tested?

A

Rotatory or optokinetic testing & Caloric testing.

60
Q

Caloric testing.

A

For vestibular function- Put cold or warm water into external acoustic meatus which will evoke endolymph convection currents. The pattern of movements are cold opposite direction saccadic eye movements to the side of fluid infusion & warm same direction saccadic eye movements – cold opposite warm same (COWS). This is why neutral temperature fluid should be used to clear ear wax

61
Q

Vestibulocollic Reflex

A

Neck movements compensate for body movement to maintain head in upright position when body is moving. Occurs with interaction with visual reflexes so when either blindfolded or vision intact head-righting will occur with vestibular damage . Damage to both no head-righting

62
Q

In adults, neck and vestibular reflexes are integrated to allow controlled movement. In young infants or in brain damaged adults these can be seen in isolation as: SAT

A

Tonic labyrinthine reflexes
Symmetric neck reflexes
Asymmetric neck reflexes

63
Q

Tonic labyrinthine reflexes are produced when

A

Head is tilted backward – arms & legs extended (superman posture)
Head is tilted forward – arms & legs flexed (rolling head over heels) or in this case head over hind paws

64
Q

Symmetric Tonic Neck Reflex

A

Tilt head forward – arms flexed & legs extended or preparing to jump off the diving board
Tilt head back – arms extended & legs flexed – jump up pose

65
Q

Asymmetric Tonic Neck Reflex occurs when

A

The head is turned – extension of the limbs in direction of head turned & contralateral flexion of the limbs -“En Garde” fencing pose

66
Q

Evaluation of the Vestibular System begins with.

A

Observation of stance and gait- Wide base of support;

Drifting side to side in gait

67
Q

Evaluation of the Vestibular System include:

A

Observation of stance and gait
Observation for spontaneous or positional nystagmus
Nystagmus testing

68
Q

Testing for nystagmus include

A

Caloric test for vestibular function
Tests of optokinetic nystagmus- can be tested visually
Electronystagmography- a recording of eye muscle activation

69
Q

Signs & symptoms of vestibular disorder WAVe

A

Wide base of support & unusual gait,
Vertigo- cardinal sign of vestibular dysfunction. Autonomic signs including: Nausea, vomiting, pallor, perspiration, blood pressure drop, tachycardia

70
Q

What is Vertigo?

A

Dizziness in which a patient inappropriately experiences the perception of motion, usually a spinning motion. symptom is often accompanied by the sign of pathologic nystagmus.

71
Q

Vestibular diseases can be either.

A

Central or peripheral

72
Q

Central vestibular disease include

A

Pathology of the vestibular nuclei, their projections or central sites of termination - result of vascular Infarct, tumors, and viral infections

73
Q

Peripheral vestibular disease involve Pathology of the

A

Labyrinth or vestibular nerve which can result from

Trauma, benign positional vertigo, neuritis, toxicity, Meneire’s disease, herpes zoster, tumors

74
Q

Benign Positional Vertigo (BPV)

A

One of the more common peripheral vestibular conditions. It is a common cause of vertigo and is due to macular debris being displaced into a semicircular canal with the posterior canal most often affected.

75
Q

Symptoms of Benign Positional Vertigo (BPV)

A

Occurs with rapid changes in head position, such as getting up from bed quickly the person gets extreme vertigo and has to lie right back down again. This can be quite disabling.

76
Q

How is Benign Positional Vertigo (BPV) diagnosed?

A

Dix-Hallpike maneuver

77
Q

Treatment of Benign Positional Vertigo (BPV)

A

A series of specific head movements to move the debris back into the macula.

78
Q

Dix-Hallpike maneuver procedure

A

First begins with the patient in a long sit position with head held by examiner. The Examiner rotates head 30-45° & assists the person to lie down, carrying head into 25-30° of extension. Movement causes otoliths to move within endolymph, creating waves of endolymph movement and bending of hair cells stereocilia in involved canal. This induces vertigo and nystagmus

79
Q

Vestibular Neuritis

A

A Unilateral vestibular disorder due to inflammation of vestibular nerve. There is a Diminished or absent response to caloric testing of horizontal canal on affected side. Symptoms include nausea and vomiting, which resolve within a few days

80
Q

Meniere’s Disease

A

An Episodic syndrome due to excess fluid in inner ear that affects hearing & equilibrium. Most commonly seen as a “ringng” in the ears – tinnitus, it can also disrupt balance. It is generally seen as Abrupt attacks which vary in frequency & severity

81
Q

Characterized of Meniere’s Disease

A

Sensorineural hearing loss, tinnitus, aural fullness, nausea & vomiting`

82
Q

Other causes of vertigo include

A

Cerebellar lesions may directly or indirectly apply pressure on the brainstem and the vestibular nuclei
Irritation of upper cervical dorsal roots
Drug and alcohol intoxication

83
Q

Types of vestibular diseases

A 
Meniere's disease
Vestibular Neuritis
Benign postural vertigo
Cerebellar lesions
Irritation of upper cervical dorsal roots
Drug and alcohol intoxication

neuro final exam (10 decks)

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