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26 Cards in this Set
- Front
- Back
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Lacrimal Gland |
-Secretes tears -Contains lysozyme (antibacterial agent) |
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How many layers does an eyelid have? |
4 |
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Eyelid Layers... |
1)SKIN (thinnest of the body)
2)MUSCLE 3)CONNECTIVE TISSUE 4)CONJUCTIVA (mucous membrane that lines eyelids and surface of eye) |
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Sclera |
White of eye, made of connective tissue, protection |
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Cornea |
Center part modified to be clear |
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Choroid Coat |
Deeper than sclera- very dark (contains melanocytes) Prevents scattering of light |
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Retina |
Innermost layer of eye- contains photoreceptor cells (rods&cones) which convert light waves to electrical signal |
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Lens |
Focuses light rays onto retina |
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Ciliary Body |
Smooth muscle that shapes lens to focus on objects (also produces aqueous humor) |
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Anterior compartment (of eye) |
Contains aqueous (watery) humor Replaced every 90 minutes; constantly drains |
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Posterior compartment (of eye) |
Is most of eyeball- contains vitreous (gel-like) humor Produced as embryo; never make more |
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Iris |
Gives you eye color, formed from smooth muscles which control pupil |
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Pupil |
Opening in iris that allows light to enter eyeball |
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Photoreceptor cells |
Located on retina When light rays are formed on retina, they stimulate photoreceptor cells Are modified neurons Rods & Cones |
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Rods |
Sensitive to light Can function in dim light Outnumber # of cones |
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Cones |
Require lots of light Provide color vision (Red, green, blue) |
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Color Blindness |
Results when one type of cone is defective |
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Optic Nerve |
Carries nervous signal to brain for interpretation and action from retina |
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Projecting the Image |
-Lens projects upside down & reversed image on retina -Optic nerve then carries image to brain to straighten it out |
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Focusing the Image |
Eye wants to focus light rays on retina The thicker the lens, the more light refracts Lens changes shape (accommodation) to focus on images close or far away |
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What happens if the image focuses incorrectly? |
Myopia or Hyperopia |
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Myopia |
Light rays focus too early (nearsighted) |
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Hyperopia |
Light rays focus too far behind retina (farsighted) |
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Cataracts |
Lens hardens and clouds |
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Glaucoma |
Liquid in aqueous humor does not drain properly and pressure builds up on retina and optic nerve |
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Astigmatism |
Condition that causes blurred vision due to either irregular shape of cornea or sometimes the curvature of the lens |
