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Eyes

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Submitted By jieannetan
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MAJOR PARTS OF THE EYE AND THEIR FUNCTIONS
Iris
* The colored part of the eye that surrounds the pupil. * It contracts and expands opening and closing the pupil, in response to the brightness of surrounding light. * This helps in dilating and making the pupil smaller.
Pupil
* The dark center of the eye, where light rays enter * The pupil either dilates or contracts with the help of the iris * This controls the amount of light entering the eye so that the retina and lens doesn't get damaged
Sclera
* Tough fibrous tissue, serves as a protective shield * Provides structure and safety for the inner workings of the eye, but is also flexible so that the eye can move to seek out objects as necessary. * Keeps the eyes shape and protects its delicate internal parts.
Retina
* Composed of nerve endings responsible for reception and transmission of light impulses.
Lens
* Transparent body located behind the iris and in front of the vitreous humor, refracts light rays to bring them into focus on the retina * The lens is a converging lens so that it can create a real image on the back wall of the eye. * This allows us to focus on something close to us and far away.
Cornea
* The cornea is the outer covering of the eye. * This dome-shaped layer protects your eye from elements that could cause damage to the inner parts of the eye. * The cornea also allows the eye to properly focus on light more effectively. * It is a specialized portion of the sclera passing in front of the lens
Conjunctiva
* These are layers of mucus which help keep the outside of the eye moist. * Cells in this lining produce mucous that helps to lubricate the eye. * This is the eyes first layer of protection against infection. Optic Nerve * This is the cable connecting the eye to the brain. * transmits impulses to brain
Eyelids
* movable folds of skin * Our eyelids protect and lubricate our eyes. * Small oil-producing glands line the inner edge of our eyelids. These oils mix with tears when we blink, keeping the eye moist and clean.
Lacrimal glands * This gland continually releases tears and other protective fluids onto the surface of the eye. * It lubricates and keeps the cornea from becoming dehydrated.
Eyelashes
* These specialized hairs protect the eyes from particles that may injure them.

http://charlesbreen.com/vision/6-major-parts-of-the-eye/ http://www.md-health.com/Parts-Of-The-Eye-And-Its-Function.html http://www.bbc.co.uk/schools/gcsebitesize/science/ocr_gateway_pre_2011/ourselves/3_keeping_in_touch2.shtml http://answers.yahoo.com/question/index?qid=20071209224412AAgqN5G http://www.99main.com/~charlief/Blindness.htm

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