visual pathway

neural components of the eye
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Terms in this set (48)
separation of NEURAL retina from RPEretinal detachmentwhen is a retinal (RPE) detachment symptomaticif in foveal area, not if its in peripheral areasplitting within sensory retina can happen in many areas split may happen in retinal layers iNNER to photoreceptorsretinoschisisfoveola fovea parafovea perifovea relative sizesfoveola: 0.35-0.5mm fovea:1.5-2mm parafovea: 3 mm perifovea: 6 mmfoveola what types of cones presentL and M (no S cones); rod-freemacula lutea - why have yellow tinge?lutein and zeaxanthin (carotenoids)macular pigment where found?in layer of henle (macula) outer segment of photoreceptorsrole of macular pigmentmitigate effects of chromatic aberration and light scattering by absorbing blue light protect retina from photo-oxidative light damagepatients with low density of macular pigment have been shown to have __________ incidence of age-related macular degenerationHIGHERmajor glial cells, help form ILM and OLM, help maintain retinal healthmuller cellsforms the blood-retina barrierOLMformed by fusion of endfeet of muller cell processes forms tight barrier between retina and vitreousILMastrocytesnerve sheaths blood-brain barrier glucose for nerve cells regulate k+ and neurotransmitter metabolism mainly in NFL, GCL, optic nervemicroglia role? where present?macrophage; immune cell ALL layers in retina when resting, NOT phagocytic ... ambeoid shape when activatedlack of blood vessels to avoid blocking of central visionfoveal avascular zoneeach optic nerve fiber in the optic nerve is an axon of the _________________ cellretinal ganglion cellhow many optic nerve fibers do humans have1-1.5 millionextent of visual field in different directionskinetic perimetrysensitivity to stimuli presented within the extent of the visual fieldstatic threshold perimetrypapillomacular bundle NFL fibers from foveal G cells take ______ path to ONHDIRECTcentrocecal scotomapapillomacular bundles scatoma between fixation point and blind spotarcuate bundles NFL from TEMPORAL G-cells take _________ pathway to ONHarchedarcuate scatomatemporal ganglion cells reduced visual sensitivitynasal bundle NFL fibers from G-cells nasal to optic disc take ___________ path to the ONHDIRECT NASAL PROBLEM WILL SHOW UP IN TEMPORAL FIELDhorizontal raphedivides the ganglion cells whose axons run below the fovea from those whose axons run above it cannot be seen in area TEMPORAL to the foveavisual field defect appears to end abruptly at horizontal meridian when either superior or inferior arcuate fibers are affected in regions near the horizontal meridiannasal stepganglion cell axons from peripheral retina lie ___________ to the vitreous and enter the ON more ________ than axons from central retinaganglion cell axons from peripheral retina lie CLOSER to the vitreous and enter the ON more PERIPHERALLY than axons from central retinawhat myelinate optic nerveoligodendrocyteswhere is the optic nerve myelinated?posterior to the lamina cribosa (blocks migration of oligodendrocytes into retina)intraocular intraorbital intranalicular intracranialintraocular: 1 mm, pass through sclera intraorbital: 23-30 mm, back of eye to optic canal intracanalicular: 5-12 mm, through canal intracranial: 8-19 mm, end of optic canal to chaismsaccades and visual fixationsuperior colliculicircadian rhythmnshypothalamuspupillary responsepretectal nucleireduced blood flowischemiademyelination, in MSinflammationincreased intracranial pressure anerurysm, neoplasm, enlarged EOMScompressionglaucoma what part of oN is primary site of injuryoptic nerve headincreased intracranial pressure transmitted to ON head, causing to swellpapilledema