C-Notes: Anatomy of the EYE Stnd: 9b C-Notes: Anatomy of the EYE 05/19/2014 Objective: SWBAT identify the structures and functions of the eye (sensory organ)

How do objects we see get detected by our eye? Our eyes is an sensory organ used for vision that takes scattered or reflected light off an object to carry information to the brain to form an image ex: if you were in a room with no light, you would not be able to see the words in your notebook because it does not give off its own light.

What are the structures of the human Eye? 1. SCLERA white, tough outermost layer helps keep the eye a spherical shape (similar to the eyes of other mammals)

6 muscles attach to the sclera

Sclera also forms the CORNEA transparent (clear) part that light passes through the pupil is an opening created by the iris, which is the colored part of the eye. To see, light passes through the cornea and enters the eye through the pupil

2. Choroid Coat middle layer of the eye supplies blood to outer layer of the retina

smooth muscles that change the shape of the lens the anterior (front) of the choroid coat forms the CILIARY BODY, IRIS, PUPIL 3. Ciliary Body smooth muscles that change the shape of the lens 4. Iris colored part of the eye 5. Pupil opening in the iris through which light enters the eye smooth muscles control the size of the pupil

6. AQUEOUS HUMOR liquid between cornea and iris maintains shape of cornea produced by the ciliary body 7. VITREOUS HUMOR clear, jelly-like liquid inside the eyeball helps maintain spherical shape of eye

8. RETINA lining of the inner surface of the eye (inner layer) contains neurons responsible for vision

Parts of the Retina Rods and Cones light receptors – 125 million rods (for “black/white” & night vision) – 7 million cones (for color vision) Fovea Centralis center of the retina – has cones only for sharp color vision Optic Disc spot where neurons come together to form the optic nerve Blind Spot no rods or cones

9. LENS biconvex: convex on both sides can change shape to focus

Disorders of the Eye Astigmatism uneven curvature of the cornea results in multiple focal points – makes images blurry

2. Myopia (near sightedness) distant objects are focused in front of the retina (eyeball is too long) can be corrected with biconcave lens

3. Hyperopia (far sightedness) image is focused behind the retina (eyeball is too short) can be corrected with a biconvex lens

4. Presbyopia ciliary muscles lose power and the person becomes farsighted – convex reading glasses help this genetic disorder – person missing cones 5. Colorblindness most colorblind people are red-green colorblind aqueous humor does not drain 6. Glaucoma results in pain and can lead to blindness as pressure inside eyeball damages retina

7. Cataracts lens becomes cloudy – usually with age

Cataract Vision

Review What is the outermost layer of the eye called? SCLERA What is the clear part of the sclera in the front of the eye called? CORNEA What is the CHOROID COAT and what is formed on the ANTERIOR part? It is the middle layer of the eye – anterior part forms the CILIARY BODY, IRIS, PUPIL What is the inner layer of the eye? RETINA What are the 4 main parts of the retina? RODS & CONES – FOVEA CENTRALIS – OPTIC DISC – BLIND SPOT

What shape is the lens? BICONVEX Where is the AQUEOUS HUMOR and the VITREOUS HUMOR located? Aqueous Humor: between the cornea and the iris Vitreous Humor: inside the eyeball

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