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25 Cards in this Set
- Front
- Back
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What would be the general effect of a lesion of the extraocular muscles?
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Double vision as image of object no longer lies on same retinal location in each eye
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What would be the effect of an isolated lesion of the abducens nerve (VI)?
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A loss of abduction beyond the midline causing diplopia (double vision) when patients attempt to look in the direction of paralyzed lateral rectus muscle.
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What would be the effect of an isolated lesion of the trochlea nerve?
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Deficits in extorsion and depression leading to skew deviation (eyes at different vertical positions)
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What would be the effects of a lesion of the oculomotor nerve?
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Loss of eye movement medially or upward from mid position.
Also drooping of eyelid (ptosis) blurred vision for near objects and pupillary dilation (mydriasis). |
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What is the main fibre tract of the vestibulo-ocular reflex?
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Median longitudinal fasciculus
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What is the sensory organ most involved in the vestibulo-ocular reflex?
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Vestibular Apparatus of Inner Ear
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What is the afferent nerve involved in the vestibulo-ocular reflex?
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Vestibular Nerve (Cranial Nerve VIII)
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What is the sensory nucleus involved in the vestibulo-ocular reflex?
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Vestibular nucleus
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What is the internuclear tract involved the vestibular ocular reflex?
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Median longitudinal fasciculus
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What is the prinicipal function of the vestibulo-ocular reflex?
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Hold images still on the retina during bried head movements.
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What do saccadic eye movements do?
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Shift the fovea rapidly to a visual target in the periphery
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What do smooth pursuit eye movements do?
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Keep the image of a moving target on the fovea
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What do vergence eye movements do
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Move the eyes in opposite directions so that the image is positioned on both fovea
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What is the primary function and innvervation of the superior rectus of the eye?
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Elevation
Oculomotor Nerve |
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What is the primary function and innvervation of the inferior rectus of the eye?
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Depression
Oculomotor Nerve |
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What is the primary function and innvervation of the lateral rectus of the eye?
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Abduction
Abducens Nerve |
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What is the primary function and innvervation of the medial rectus of the eye?
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Adduction
Oculomotor Nerve |
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What is the primary function and innvervation of the superior rectus of the eye?
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Elevation
Oculomotor Nerve |
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What is the primary function and innvervation of the inferior rectus of the eye?
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Depression
Oculomotor Nerve |
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What is the primary function and innvervation of the lateral rectus of the eye?
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Abduction
Abducens Nerve |
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What is the primary function and innvervation of the medial rectus of the eye?
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Adduction
Oculomotor nerve |
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What is the primary function and innvervation of the Superior Oblique muscle of the eye?
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Intorsion & Depression
Trochlear nerve |
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What is the primary function and innvervation of the inferior oblique of the eye?
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Extorsion and elevation
Oculomotor |
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Via what nerve does innervation of the ciliary muscle travel?
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Oculomotor
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What would be the effect of the ciliary muscle acting alone?
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Contraction releases tension on the lens causing it to become shorter and fatter allowing the eye to focus on nearer objects.
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