External Layer Eye Protection Conjunctiva membrane lining the inside of eyelids and across the front of the eye Prevents objects from moving behind the eye Fat Deposits Cushioning the eye during impacts ID: 1047427
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1. HOW WE SEE!
2. Eye Structure
3. External Layer
4. Eye ProtectionConjunctivamembrane lining the inside of eyelids and across the front of the eye. Prevents objects from moving behind the eye.Fat DepositsCushioning the eye during impacts.ScleraStrong outer membrane. Gives shape to eye, and helps with accommodation.
5. Intermediate Layer Choroid – absorbs scatter light, includes blood vessels (food)Iris – regulates amount of light enteringPupil – opening of lightCiliary muscles – change shape of lens to focus
6. Fat Depositsa close energy sourceChoroid layerenriched with blood vessels. Brings in nutrients and removes wastes.Nourishment
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8. Nourishment (cont.)Posterior Chamber filled with Vitreous Humourbrings nutrients to the lens.Pores in the ciliary musclesallow nutrients to diffuse from the posterior to the anterior chamber.Anterior Chamber filled with Aqueous Humourbrings nutrients to the cornea and the front of the lens.
9. Internal LayerRods – light receptorsCones – color receptorsFovea centrailis – high density of cones, provides acute vision
10. Other Noteable StucturesLens – focuses lightHumours -support eyeball with pressure of fluidsOptic nerve – transmitter to brainOptic disc – blind spot, where nerve connets with eyeWatch Crash Course A&P 18https://youtu.be/o0DYP-u1rNM?list=PL8dPuuaLjXtOAKed_MxxWBNaPno5h3Zs8
11. Objects focus on RetinaThe image is focused on the fovea centralis is:SmallerUpside downReversed left and right
12. Vision (cont.)RetinaConverts light energy to nervous impulsesRodsdetect shades of black and white, excellent with motion, can work in low light. (peripheral)ConesDetect colour, excellent with detail, require lots of light. (central vision) - http://wimp.com/colorblind/ Fovea Centralis (Macula)Filled with only cones (for detail vision)
13. Vision (cont.)Retina (cont.)Blind SpotArea where optic nerve leaves eye. No room for sensory receptors.
14. Reflexes of SightLight reflexbright light causes the iris to enlarge and the pupil to get smaller, while low light causes the opposite.Accommodation Reflexpupil size and lens shape changes with distance. For far objects the lens is stretched flat, while for close objects it bulges out.
15. Chemistry of SightRods and Cones contain rhodopsin pigments.Rhodopsin is made up of Vitamin A and Opsin.
16. Chemistry (cont.)When rhodopsin is struck by light it splits and alters the cell chemistry, causing the neuron to fire.
17. Chemistry (cont.)Cones see color by using three types of rhodopsin; one for each primary color (Red, green, blue).If you are colour blind, you have deficiency in a specific cone type.
18. Depth PerceptionMemory (brain)The size a known object has in your brain.Moving parallax (diff distances, diff speed)When you move your head from side to side, objects that are close to you move rapidly across your retina. However, objects that are far away move very little.Stereo vision (overlapping fields of view)Each eye receives a different image of an object on its retina because each eye is about 2 inches apart.
19. Brightness PerceptionThe brightness of an object depends on the light reflected from itself and its background.
20. Nearsightedness (Myopia)Able to see near objects well and has difficulty seeing objects that are far awayThe image is focused in front of the retinaCorrected with concave lens
21. Farsightedness (Hyperopia)Is present, a person is able to see distant objects well and has difficulty seeing objects that are near.Image is focused behind the retinaCorrected with a convex lens.
22. AstigmatismUneven curvature of the cornea and causes a distortion in vision.Corrected with a shaped lens.
23. BlindnessNight Blindnesssevere vitamin A deficiency leads to a lack of rhodopsin.CataractsGlaucomaDiabetic Retinopathy
24. Glaucoma increased pressure within the eyeball.aqueous humor builds up and increases pressure within the eye. damage the optic nerve directly or restrict blood flow, thus damaging the optic nerve indirectly.lead to blind spots in the visual field. can cause permanent blindness.
25. Glaucoma
26. Cataractsthe lens becomes cloudy.Cataracts are caused by changes in the chemical makeup of the lens.With age, the lens becomes thicker and less clear.
27. Cataracts
28. Diabetic Retinopathy Diabetic retinopathy refers to damage to the blood vessels of the retina caused by diabetes. As new blood vessels grow on the retina, blurred vision or temporary blindness can result.Scare tissue can form and cause blindness where old blood vessles were attached to the retina.
29. Diabetic Retinopathy
30. FOR FUN!
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33. Connectivity
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