Deck 16: Vestibular and Visual Systems

Question 1

Why is it important that each pair of semicircular canals produce reciprocal signals?

A)The canals never produce reciprocal signals.
B)Difficulties with control of posture,abnormal eye movements,and nausea will result if the signals are not reciprocal.
C)Difficulties in sensing forward motion will result if the signals are not reciprocal.
D)Difficulties in sensing up and down motion will result if the signals are not reciprocal.

Answer 1

B
Explanation: Each of the canals in a pair produces reciprocal signals;that is,increased signals from one canal simultaneously occur with decreased signals from its partner.These reciprocal signals are essential for normal vestibular function.If the signals from a pair of semicircular canals are not reciprocal,difficulties with control of posture,abnormal eye movements,and nausea result.The maculae,not the semicircular canals,sense forward motion.

Question 2

The medial longitudinal fasciculus is a bilateral axonal pathway between the vestibular nuclei and which of the following?

A)Cranial nerve nuclei III,IV,and VI
B)Superior colliculus
C)Cranial nerve nuclei XI
D)A and B
E)A,B,and C

Answer 2

E
Explanation: The medial longitudinal fasciculus (MLF)consists of axons that connect cranial nerves III,IV,VI,and XI and the superior colliculus.The MLF coordinates eye and head movements.

Question 3

Which of the following is a role of the vestibular system?

A)Postural adjustments
B)Provides sensory information
C)Gaze stabilization
D)All of the above

Answer 3

D
Explanation: In addition to providing sensory information about head movement and position,the vestibular system has two roles in motor control: gaze stabilization and postural adjustments.

Question 4

The path of the optic nerve passes from the _____________ to the _______________.

A)Optic chiasm;lateral geniculate
B)Retina;lateral geniculate
C)Retina;optic chiasm
D)Cortex;retina

Question 5

What movements are necessary to accomplish gaze?

A)Saccades,smooth pursuits,and vergence movements
B)Saccades,smooth pursuits,and cilial movements
C)Saccades and vergence movements only
D)Saccades and smooth pursuits only

Question 6

Information from the right visual field is conveyed to which of the following?

A)Left lateral geniculate and left visual cortex
B)Right lateral geniculate and right visual cortex
C)Bilateral geniculate then left visual cortex
D)Bilateral secondary visual cortices
E)Right pretectal area of superior colliculus

Question 7

The Hallpike maneuver was designed to:

A)Elicit the vestibulo-ocular reflex.
B)Rupture the cupula.
C)Provoke maximal movement of otoconia in the horizontal semicircular canals.
D)Provoke maximal movement of otoconia in the posterior semicircular canals.
E)Treat dizziness associated with central vestibular lesions.

Question 8

Damage to the right frontal eye fields may result in which deviation in visual control?

A)Tropia
B)Abnormal vestibulo-ocular reflexes
C)Rotary nystagmus
D)Ptosis
E)Persistent ipsilateral gaze

Question 9

What is the most common cause of near syncope?

A)Perilymph fistula
B)Somatosensory deficits
C)Cardiovascular disorders
D)Psychologic or stress disorders
E)Motion sickness

Question 10

If light from the right visual field strikes the retina,where does it strike?

A)Left half of each retina
B)Right half of each retina
C)Bottom of the retina
D)Top of the retina

Question 11

Lateropulsion may occur with a lesion to which of the following?

A)Parietoinsular cortex
B)Dorsolateral medulla
C)Inferior cerebellar peduncle
D)Vestibular nuclei
E)All of the above

Question 12

Which of the following is a sign of the ocular tilt reaction?

A)Lateral head tilt
B)Skew deviation of the eyes
C)Ocular rotation
D)A and B
E)A,B,and C

Question 13

Vestibular connections influence which of the following?

A)Posture of the head and body
B)Head and eye movements
C)Consciousness
D)Autonomic functions
E)All of the above

Question 14

The ___________ vestibulospinal tract is the primary tract for vestibular influence on lower motor neurons to postural muscles in the limbs and trunk.

A)Lateral
B)Medial
C)Anterior
D)Posterior

Question 15

To detect a movement of the head,receptors in the semicircular canals sense motion in which of the following?

A)Cilia
B)Crista
C)Endolymph
D)All of the above

Question 16

Vertigo accompanied by sensory and/or motor loss,diplopia,and dysarthria is indicative of a lesion of which of the following?

A)Cerebellum
B)Vestibulothalamocortical pathway
C)Brainstem
D)Bilateral Benign Paroxysmal Positional Vertigo (BPPV)
E)All of the above

Question 17

The functions of the vestibulocerebellum are to receive vestibular information and to ___________________.

A)Send signals to the semicircular canals
B)Prevent adaptation to vestibular disorders
C)Influence the speed of movement
D)Influence eye movements and postural muscles

Question 18

How do the vestibular connections with the reticular formation affect the autonomic nervous system?

A)Vestibular connections with the reticular formation do not affect the autonomic nervous system.
B)Excessive activity of the circuits linking vestibular nuclei and the reticular formation may result in nausea,vomiting,and changes in consciousness.
C)Activity of the circuits linking vestibular nuclei and the reticular formation prevents any nausea,vomiting,and changes in consciousness.
D)Vestibular connections with the reticular formation calm the autonomic nervous system.

Question 19

Projections from the vestibular nuclei contribute to which of the following?

A)Postural adjustments
B)Autonomic function and consciousness
C)Gaze stabilization
D)All of the above

Question 20

What is the most common symptom of vestibular dysfunction?

A)Nausea and vomiting
B)Limb ataxia
C)Disequilibrium
D)Vertigo
E)Upward beat nystagmus