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26 Cards in this Set
- Front
- Back
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Orthograde Transport
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GC bodies to lateral geniculate
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Retrograde Transport
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Lateral Geniculate to GC bodies
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Magnocellular Axons
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large diameter, fast conduction, large receptive fields, high sensitivity in dim light (carry ROD signals)
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Parvocellular Axons
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small diameter, slow conduction, small receptive fields, sensitive to color and detail (carry CONE signals)
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Papillomacular Bundle
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nerve fibers from macula
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Superotemporal and Inferotemporal fibers
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most susceptible to glaucomatous damage; arc around papillomacular bundle
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1.5-1.9mm
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average diameter of optic disc
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67 million
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number of cases of glaucoma worldwide
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6.7 million or 10%
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number with bilateral blindness due to glaucoma
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raphe
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midline
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4 regions of optic nerve
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nerve fiber layer, prelaminar, laminar, retrolaminar
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Inner limiting membrane of Elschnig
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separates vitreous from from NFL (formed by astrocytes)
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Where are the openings in the lamina cribosa largest?
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superotemporally and infratemporally (this lack of structural support is one reason axons in these distributions are more susceptible to damage)
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Where does the optic nerve diameter double and why?
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posterior to the lamina cribosa due to myelination
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Describe the spatial configuration of ganglion cell bodies with respect to the location of their axons within the optic nerve
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Peripheral GC --> outer disc
Central GC --> inner disc |
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Central Meniscus of Kuhnt
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central and anterior-most portion of the disc continuous with the ILM of the retina and the ILM of Elschnig
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1.2 million
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number of axons coursing through the optic nerve
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1,000
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number of fascicles in the optic nerve
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Mechanical Theory
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disruption of axoplasmic flow due to physical compression of the axon leading to apoptosis
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Vascular Theory
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loss of autoregulation in optic nerve vessels causes ischemia
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Average IOP in US
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15mmHg (+/- 2 SDs 10-21mmHg)
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Average diurnal IOP deviation
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3-6mmHg (higher variation is correlated with more damage)
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What does Tonography measure?
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Aqueous outflow (measured as the rate at which a Schiotz tonometer forces aqueous from the trabecular meshwork--the slope of the plotline)
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What aqueous flow parameter is primarily responsible for increased IOP?
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outflow
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What measures aqueous production?
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Fluorophotometry (based on rate of fluoroscein clearance from the AC) research only
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Imbert-Fick Formula
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P=F/A (principle employed by Goldmann Applanation)
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