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24 Cards in this Set
- Front
- Back
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What produces eye movements?
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six extra-ocular muscles
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What are accomodation and pupillary responses produced by?
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intraocular muscles
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What is the condition when the eye movement control system has gone awry? What usually causes it? Does it resolve?
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opsoclonus or saccadomania
viruses yes |
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What are saccades?
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rapid eye movements
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What happens when the left CN VI is damaged?
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gaze to the right is normal but when looking to the left the left eye stayed center
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What adducts the eye?
What aBducts the eye? |
medial rectus
lateral rectus |
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What elevates the eye?
What depresses the eye? |
superior rectus
inferior rectus |
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What is intorsion? What intorts the eye?
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eye rotates in
superior oblique |
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What is extorsion? What extorts the eye?
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eye rotates out
inferior oblique |
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What controls positive accodmodation? What is unique about this muscle?
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ciliary muscle;
it does not have an antagonistic muscle |
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What acts as an antagonist to the ciliary muscle?
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suspensory ligaments
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What causes pupil constriction? What is this innervated by?
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sphincter pupillae;
parasympathetic NS |
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What causes pupil dilation? What is it innervated by?
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dilator pupillae;
sympathetic innervation |
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Is there a stretch reflex in the eyes?
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no, it is absent
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T/F: Proprioceptive feedback from the extraocular muscles is used to keep track of eye position.
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False
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How does the brain keep track of eye position? What is the name for this?
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by keeping track of the signals sent to the motorneurons that innervate the extraocular muscles;
efference copy or corolloary discharge |
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What is corollary discharge?
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a copy of the signal that you send to the muscles, used to keep track of eye position
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What is spatial constancy? What signal is used to maintain spatial constancy?
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a signal that appears in the parietal cortex such that as you move your eyes left and right the external world is being imaged on different parts of the retina for every eye movement and yet the world does not seem to move;
efference copy of the signal (corollary discharge) |
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When are eye movements not yoked?
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changes in viewing distance
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T/F: Normal eye movements are yoked.
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T (except for changes in viewing distances)
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Are vertical eye movements yoked?
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almost always
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What is the underlying anatomy that preserves the yoking of the eyes?
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projection from the abducens nucleus by way of the MLF
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Where do abducens internuclear neurons project?
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through the contralateral MLF to the nucleus of CN III to the contralateral medial rectus motor neurons
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What happens when the lateral rectus on one side contracts?
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that information is relayed to the medial rectus motor neurons on the other side so that the medial rectus will contract
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