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23 Cards in this Set
- Front
- Back
What is being seen in each step of the visual pathway?
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1) Optic Nerve - portion of left and right hemifield
2) optic chaism - nasal retinas cross which each see the contralateral peripheral visual feild 3) optic tract - contralateral visual hemifield (macula + that side and periphery) 4)LGN - contralateral visual hemifield 5) Meyer's loop - contralateral superior portion of the visual hemifield 5) parietal optical radiation - contralateral inferior portion of the visual hemifeild 6) cuneus gyrus - contralateral inferior visual hemifield with the macular region spared 7) lingual gyrus - contralateral superior region of the visual field with the macula spared |
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What is it called when you get a visual field defect in the optic nerve?
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Monocular blindness
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What do you lose when you get a visual field defect in the optic nerve?
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blindness in one eye, nasal portion of contralateral field and temporal portion of ipsilateral field
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What do you call a visual defect that occurs in the optic chiasm?
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bitemporal heteronymous hemianopsia
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What do you lose when you have a visual defect in the optic chaism?
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bilateral periperhal vision lost
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What is it called when you have a defect in the optic tract?
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contralateral homonymous
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What do you lose/what do you see when you have a visual defect in the optic tract?
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-blindness in contralateral temporal visual field and ipsilateral nasal visual field
-complete loss of vision in affected region of binocular field you lose the contralateral visual hemifeild. so if you have a lesion in the optic tract of the right eye you lose the left hemifield. so that means you lose the left side of your right visual field and the left side of your left visual field |
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What do you call a defect in Meyer's loop?
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contralateral superior homonymous quadratanopsia
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What do you call a defect in the parietal portion of the optic radiations?
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contralateral inferior homonymous qaudratonopsia
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What do you call the defect in the cuneus gyrus?
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contralateral inferior qaudratanopsia with macular sparing
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What do you call the defect in the lingual gyrus?
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contralateral superior quadratanopsia with macular sparing
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What are the three reflexes associated with the near response?
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1) convergence
2) accomodation 3) pupillary constriction |
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What is the mechanism of convergence?
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medial rectus muscles contract to move both eyes towards midline so image remains focused at fovea
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What is the mechanism of accomodation?
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lenses are thickened due to contraction of ciliary muscles to maintain a focused image
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What are the two nerves that mediate the corneal reflex?
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1)trigeminal nerve opthalmic divsion senses touch, etc
2) sensory cell body is in the trigeminal ganglion 3)synapses at spinal root and trigeminal nucleus 4) an interneuron travels to the motor nuclei of CN VII 5) efferent is dispatched to contract orbicularis oculi |
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What is miosis?
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constriction of pupil
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What is myhydriasis?
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dilation of pupil
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What is the innervation of the pupillary light reflex?
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1) retinal ganglion cells project to pretectum
2) pretectum recieves projects from both eyes 3) pretectum projects to edinger westphal nucleus bilaterally 4) edingerwestphal contains preganglionic PS neurons that travel with occulomotor nerve 5) occulomotor nerve goes to ciliary ganglion and synapse 6) post ganglionics innervate ciliary and spinchter pupillae muscles |
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What is the Argyll Robertson pupil?
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accomodate but do not react to light
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What are Adie's tonic pupils/Holme's Adies syndrome?
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tonically dilated pupil because damaged PS innervation of eye
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What is aniscoria?
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unequal pupils
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What is the consensual resposne?
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pupillary constriction of opposite unstimulated eye
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What do you use to test visual field?
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humphrey visual field test
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