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Lecture 19

PSYC 211 Lecture Notes - Lecture 19: Visual Acuity, Peripheral Vision, Vitreous BodyPremium

2 pages49 viewsFall 2015

Department
Psychology
Course Code
PSYC 211
Professor
Yogita Chaudasama
Lecture
19

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37
Lecture'#19'
Anatomy'on'the'Eye'(I)'
- the$cornea$is$the$outer,$front$layer$of$the$eye.$It$is$transparent$and$admits$light,$sensitive$to$day$
time$and$night$time$$
- the$iris$is$a$pigmented$ring$of$muscle$
- the$lens$consists$of$several$transparent$layers.$The$ciliary'muscles$can$change$the$shape$of$the$
lens$which$increases$the$size$of$the$pupil$to$allow$the$eye$to$focus$depending$on$how$much$light$
the$lens$is$letting$the$pupil$take$in,$a$process$known$as$accommodation$
- the$pupil$regulates$the$amount$of$light$entering$the$eye.$It$is$an$opening$in$the$iris$
- the$sclera$is$opaque$and$does$not$permit$entry$of$light$
- conjunctiva$is$a$mucous$membranes$that$line$the$eye$and$merges$with$the$inside$if$the$eyelids$
Anatomy'of'the'Eye'(II)'
- the$interior$lining$of$the$is$the$retina$
- photoreceptors$called$rods$(sensitive$to$low$light$intensityà$vision$in$the$dark)$and$cones$
(essential$for$color$vision,$therefore$useful$in$bright$light$and$daytime$vision)$are$located$in$the$
retina$
- light$passed$though$the$lens$and$crossed$the$vitreous'humor,$a$clear,$gelatinous$fluid$
- the$central$region$of$the$retina$is$the$fovea.$It$contains$the$highest$number$of$cones$
- site$of$blind'spot$is$the$point$at$which$the$optic$nerve$exists$through$the$back$of$the$eye.$It$has$no$
receptors$and$therefore$there$is$no$vision$
$
The'Route'within'the'Retina'
- light$passes$through$transparent$cells$and$stimulate$the$photoreceptors$located$at$the$back$of$the$
eye$
- photoreceptors$then$send$messages$to$bipolar$and$ganglion$cells$located$closer$to$the$center$of$
the$eye$
- the$ganglion$cells’$axons$loop$around$each$other$and$travel$back$to$the$brain$
- optic$nerve$is$connected$to$the$retina$and$is$comprised$of$various$number$of$cell$bodies,$retinas$
and$photoreceptors$
- the$receptors$send$their$messages$to$bipolar$and$horizontal$cells,$which$in$turn$send$messages$to$
the$amacrine$and$ganglion$cells.$The$axons$of$the$ganglion$cells$loop$together$to$exit$the$eye$at$the$
blind$spot.$They$form$the$optic$nerve$which$continues$to$the$brain$
Cellular'Structure'of'the'Retina'
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