1. Eyes
3.03 Remember the structures of the sensory system 1

2. 3.04 Understand the functions and disorders of the sensory system
Warm up
Read pages in textbook. Fill out handout.
3.04 Understand the functions and disorders of the sensory system

3. Structures of the eyes External structures Orbit Eyelids Eyelashes
Conjunctiva
Lacrimal apparatus
Extrinsic muscles
3.03 Remember the structures of the sensory system 3

4. Structures of the eyes 1” in diameter
Protected by orbital socket of skull, eyebrows, eyelashes and eyelids
Bathed in fluid from LACRIMAL GLANDS – tears empty into nasal cavity
CONJUNCTIVA – thin membrane that lines the eyelids and covers part of the eye, secretes mucous to lubricate eye
Wall of the eye made up of three coats (sclera, choroid coat, retina)
Two Chambers
Anterior containing iris, ciliary body and lens
Posterior- retina, macula, optic nerve.
3.03 Remember the structures of the sensory system 4

5. 3.04 Understand the functions and disorders of the sensory system
Eye
External eye
Orbit
Eyelids and eyelashes
Women blink twice as often as men. Why do we blink?
Conjunctiva
Lacrimal apparatus
Extrinsic muscles
Interesting
tidbit
3.04 Understand the functions and disorders of the sensory system

6. Which extrinsic muscle allows you to look upward?
Eye
External eye
Extrinsic muscles- 4
Superior rectus, Inferior rectus, Medial rectus and Lateral rectus
Which extrinsic muscle allows you to look upward?
3.04 Understand the functions and disorders of the sensory system

7. 3.04 Understand the functions and disorders of the sensory system
Eye
Internal eye
Sclera
Outer layer
White of the eye
Tough coating, helps maintain shape of eye and protects what’s inside
Muscles responsible for moving the eye are attached to the sclera – called EXTRINSIC MUSCLES
3.04 Understand the functions and disorders of the sensory system

8. 3.04 Understand the functions and disorders of the sensory system
Internal eye
Cornea-  the transparent front part of the eye that covers the iris, pupil, and anterior chamber Refracts light.
Choroid Coat-
Layer of the sclera that contains the blood vessels-Blood supply to the eye
Eye
3.04 Understand the functions and disorders of the sensory system

9. 3.04 Understand the functions and disorders of the sensory system
Internal eye
Iris-
thin, circular structure in the eye, responsible for controlling the diameter and size of the pupil-the amount of light reaching the retina. The color of the iris is often referred to as “ eye color “
Pupil
a hole located in the center of the iris of the eye that allows light to enter the retina
Eye
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10. 3.04 Understand the functions and disorders of the sensory system
Eye
Internal eye
Ciliary body- Muscles inside the eye -has three functions: accommodation, aqueous humor production and the production and maintenance of the lens zonules
Lens-  a nearly transparent biconvex structure suspended behind the iris of the eye, the sole function of which is to focus light rays onto the retina
3.04 Understand the functions and disorders of the sensory system

11. 3.04 Understand the functions and disorders of the sensory system
Internal eye
Aqueous humor
clear, watery fluid circulating in the chamber of the eye between the cornea and the lens. 
- nourishes the cornea and the lens and gives the eye it's shape.
Eye
3.04 Understand the functions and disorders of the sensory system 11

12. 3.04 Understand the functions and disorders of the sensory system
Internal eye
Vitreous humor-  clear gel that fills the space between the lens and the retina.
Helps keep the retina in place
Eye
3.04 Understand the functions and disorders of the sensory system 12

13. 3.04 Understand the functions and disorders of the sensory system
Eye
Internal eye
CHOROID COAT
Middle layer
Blood Supply to retina
Opening in front is the PUPIL
Colored, muscular layer surrounding pupil is IRIS
INTRINSIC MUSCLES – change size of iris to control amount of light entering through the pupil
3.04 Understand the functions and disorders of the sensory system 13

14. 3.04 Understand the functions and disorders of the sensory system
Internal eye
RETINA
Innermost layer
Light rays focus an image on the retina
The image travels to the cerebral cortex via the OPTIC NERVE
Receives light focused from the lens, convert the light into neural signals, and send these signals on to the brain.
Eye
3.04 Understand the functions and disorders of the sensory system 14

15. Eyes Rods and cones- specialized nerve fiber in the retina.
Rods- Located on the pouter edges of the retina
Do not perceive color
Function in dim light allowing us to see and also helps with peripheral vision
Cones
Active in bright light and allow you to precieve color
If you don’t have cones you are considered color blind.
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16. 3.04 Understand the functions and disorders of the sensory system
Internal eye
OPTIC DISC – Located on the retina on the back of the eye.
Known as the blind spot – nerve fibers gather here to form the optic nerve, no rods or cones
1 Million Neurons
Eye
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17. 3.04 Understand the functions and disorders of the sensory system
Eye
What is the macula?
a small and highly sensitive part of the retina responsible for detailed central vision.
3.04 Understand the functions and disorders of the sensory system

18. Eye Process of Seeing Trace the field of vision.
Light
Cornea
Pupil
Lens (where light rays are refracted)
Retina
Rods and Cones (pick up stimulus)
Optic Nerve
Brain
Is there anything strange about this picture? Explain
Why can’t you see in the dark?
3.04 Understand the functions and disorders of the sensory system

19. What happens as you move your paper away from and
Eye
Vision
What happens as you move your paper away from and
toward to your eye?
3.04 Understand the functions and disorders of the sensory system

20. Eyes Name the structures… Review 20
3.03 Remember the structures of the sensory system

21. 3.04 Understand the functions and disorders of the sensory system
Check your knowledge!
3.04 Understand the functions and disorders of the sensory system

22. 3.04 Understand the functions and disorders of the sensory system
Vision Activity
Do you see what I see?
3.04 Understand the functions and disorders of the sensory system

23. Disorders of the eye Presbyopia Astigmatism Glaucoma
Diabetic retinopathy
Detached retina
Hyperopia
Color blindness
Cataract
Myopia
Conjunctivitis
Have you heard of these conditions?
What do you know about them?
3.04 Understand the functions and disorders of the sensory system

24. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Cataract
Describe this lens.
3.04 Understand the functions and disorders of the sensory system

25. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Cataract
How is a cataract treated?
3.04 Understand the functions and disorders of the sensory system

26. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
CATARACTS
Lens of eye gradually becomes cloudy
Frequently occurs in people over 70
Causes a gradual blurring and loss of vision
Pupil turns from black to milky white
Rx – surgical removal of the lens
3.04 Understand the functions and disorders of the sensory system

27. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Color blindness
Do you see the number?
Unable to distinquish between the colors red and green. Will most often only be able to see black, white and gray.
A decrease in the number of rods in the eye.
Men are more likely to be color blind
Ishihara chart
3.04 Understand the functions and disorders of the sensory system

28. How is conjunctivitis spread?
Disorders of the eye
Conjunctivitis
Pink eye
Inflammation of conjunctival membranes in front of the eye
Redness, pain, swelling and discharge
Highly contagious
Rx – antibiotic eye drops
How is conjunctivitis spread?
How can it be prevented?
3.04 Understand the functions and disorders of the sensory system

29. 3.04 Understand the functions and disorders of the sensory system
Detached retina
Discuss what happens in this process.
What is the relevance to health?
3.04 Understand the functions and disorders of the sensory system

30. 3.04 Understand the functions and disorders of the sensory system
Detached retina
Compare this process to the previous picture.
What might cause this condition?
3.04 Understand the functions and disorders of the sensory system

31. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Diabetic retinopathy
What causes diabetic retinopathy?
What are the symptoms?
Explain the impact on vision.
3.04 Understand the functions and disorders of the sensory system

32. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Glaucoma
Excessive intraocular pressure causing destruction of the retina and atrophy of the optic nerve
Caused by overproduction of aqueous humor, lack of drainage, or aging
Sx – develop gradually – mild aching, loss of peripheral vision, halo around the light
TONOMETER – measures intraocular pressure
Rx – drugs or laser surgery
3.04 Understand the functions and disorders of the sensory system

33. 3.04 Understand the functions and disorders of the sensory system
Disorders of the eye
Macular degeneration
What is macular degeneration?
Compare the two types.
How is it diagnosed?
What is the treatment?
3.04 Understand the functions and disorders of the sensory system

34. 3.04 Understand the functions and disorders of the sensory system
Problems with Focus
3.04 Understand the functions and disorders of the sensory system

35. 3.04 Understand the functions and disorders of the sensory system
PRESBYOPIA
Lens loses elasticity, can’t focus on close or distant objects
Usually occurs after age 40
Rx – Bifocals
HYPEROPIA
Farsighted
Focal point beyond the retina because eyeball too short
Convex lenses help
3.04 Understand the functions and disorders of the sensory system

36. 3.04 Understand the functions and disorders of the sensory system
MYOPIA
Nearsighted
Eyeball too long
Concave lenses help
ASTIGMATISM
Irregular curvature of the cornea or lens, causing blurred vision and eye strain
Rx – corrective lenses
3.04 Understand the functions and disorders of the sensory system

37. 3.04 Understand the functions and disorders of the sensory system
Testing vision
SNELLEN EYE CHART – chart that uses letters or symbols in calibrated heights to check for vision defects
3.04 Understand the functions and disorders of the sensory system

38. Processing
Labeling Activity 1
Look into my eyes