eyeball project

8/8/2019 Eyeball Project

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-THE-


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A SYSTEM IS A COLLECTION OF

OBJECTS THAT WOULD BECOMPLETELY IRRELEVANT

TO ONE OTHERHAD THEY NOT BEEN PUT TOGETHER

AS A COMPLEX WHOLE


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The Cornea

Lights passage into the brain begins withthe cornea.The cornea isthe clear, protective film covering your pupil soyou dontaccidentally stick a pencil into youreyeball anddamageany necessary agentsthathelp you see.The cornea

also keeps in the vitreous (a kind of gel in youreyethathelpsyoureyeball retain itsshape)and slightly bendsthe lighttodirect it into your pupil.

Cornea


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The Iris

The iris, much liketheshutter ofa camera lens, isthe

colorful part of youreyethathelps diminishtheamount of light

that passesthrough your pupil. If you didnthavean iris, then

you would gettoo much light on a bright day and too little light

on a day you find yourselfsitting in a dungeon. And if youdidnthavean iris, everyone would look really boring and

creepy.

Iris


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The Pupil

The pupil isthat littlehole inside of your iris on your

eyeball.The pupil is wherethe light comes in through. If you

wereto stick your finger into youreyeto see if it was really a

hole, though, you wouldnt feel it because of your corneaand

would only succeed in hurting yourself, so take my word for it.

Pupil


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The Lens

The crystalline lens is, basically, a lensstuck inside of

youreyeball. It focusesthe light into your retina, just likea

contact lens or pair of glasses. If youreye wasa camera, then

your lens would bea lens. Sorry, but from now on its going

to be really complicated.

Lens


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TheRetina

The retina isthe film ofthe camera. Withoutthe retina,

youre justan idiot pressing a button on a plastic box.The

retinahas many layers:The pigmentepithelium (the layerthat

contains pigment used to absorb stray light rays), the

photoreceptor layer (the layerthatsignals colors), the bipolarcells (the layerthattransmitssignals from the photoreceptors

to the ganglion cells), and ganglion cells (the layerthat

transmitsthe retinal information to the midbrain).

Retina


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Rodsand Conesand MORE

The photoreceptor cells dont collect information on color

individually; they get information from a wide variety of

photoreceptors called rodsand cones.These rodsand

cones reactto light, orto beexact, theabsence of light.The

darker it is, the more glutamatethey release. Afterthe bipolarcellstransmitthesesignalsto the ganglion cells, they can be

interpreted asa whole, and then they arealmosttranslated

into a color. You can almostsee now.

Photoreceptors


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Optic Nerves

The ganglion cells now haveall the information it needs;

it just needsto getsomewhere. Almostevery sensory

instrumenthasaxons:the connections between neuronsthat

transmitelectric impulses.The ganglion cellssend impulses

throughtheiraxonstoward the optic nerves. An interestingfact isthatthe ganglion axonshaveto travel from the back of

the retina forward to reachthe optic nerves. Sincethis blocks

part ofthe retina, it createstheso-called blind spot.

Optic Nerves


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Lateral Geniculate Nucleus

The optic nerve passesthroughthis cerebral peduncleto be

interpreted into color, images, intensity, and brightness. Its

like going on a road trip in Spain and discovering you havea

road map, tour guide, and bottle you thinkis digestible but

youre notsure, so you stop ata gasstation and getsome

stuff in English.

http://www.pbs.org/saf/1507/teaching/teaching.htm

Lateral Geniculate

Nucleus


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Cortex

Everything you haveeverseen has

landed in this little gray nugget. Now you

can see.

Congratulations.http://www.pbs.org/saf/1507/teaching/teaching.htm

Primary

Visual

Cortex


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Sites

http://pathology.mc.duke.edu/neuropath/naw

r/sensory.html#visual

http://emeraldeye.com/eyeAnatomy.htmhttp://library.med.utah.edu/kw/hyperbrain/syl

labus/syllabus7.html

http://webvision.med.utah.edu/anatomy.html

eyeball project

Documents