1. Do Now
Research the following diseases and give a sentence summarizing them
Glaucoma
Conjunctivitis
“Floaters”
Corneal Abrasion
Astigmatism
Night vision blindness

2. 10.9
Sense of Sight

3. Happy Cow Eye Day!!

4. Objectives To identify different visual accessory organs.
To compare and contrast rods and cones.
To explain various diseases of the eye.

5. Accessory Organs of the Eye
Eyelids: contain skin, muscle, connective tissue, and conjunctiva.
Main Eye Muscles:
Orbicularis Oculi: closes lid upon contraction.
Levator Palpebrae Superioris: opens lid

6. Accessory Organs of the Eye
Conjunctiva: mucous membrane lining eyelids and anterior surface of eyeball (except the cornea)
Lacrimal Apparatus:
Lacrimal gland- secretes tears
Superior and inferior canaliculi- collect tears
*Tears contain lysozyme which acts as an antibacterial agent.

7. “Conjunctivitis”
Inflammation of the conjunctiva. Can be caused by a viral infection or an allergic reaction. Most commonly caused by bacteria which people call “Pink Eye”

8. Accessory Organs of the Eye
Extrinsic Eye Muscles:
Superior Rectus
Inferior Rectus
Medial Rectus
Lateral Rectus
Superior Oblique
Inferior Oblique

9. Accessory Organs of the Eye
Extrinsic Eye Muscles:

10. Eye Structure
*The eye is about 2.5cm and is hollow It contains 3 layers 1) An outer fibrous layer 2) A middle vascular layer 3) Inner nervous layer

11. Outer Layer Cornea: Sclera: (the white part)
focuses entering light rays
Made of connective tissue + epithelium
Avascular
Sclera: (the white part)
Collagenous + elastic fibers
Protects eye
Provides a place for muscle attachment

12. “Astigmatism”
Curvature of the eye is incorrect and causes blurriness or distorted vision

13. Middle Layer Choroid coat: Ciliary Body: Lens: Provides blood vessels
Contains melanocytes
Ciliary Body:
Aids in focusing
Holds lens in place
Lens:
Changes shape to focus
Flat=focus on distance
Convex=focus on close objects.

14. “Myopia” “nearsightedness”
Person has trouble seeing things that are far due to thick cornea or lens or an elongated eyeball
Prescribed a concave lens

15. “Hyperopia” “farsightedness”
Person has trouble seeing things that are close due a short eyeball, shallow cornea or thin lens
Prescribed a convex lens

16. Middle Layer (cont.) Iris: Pupil: Aqueous Humor: Colored part
Contains muscles that control pupil size
Divides anterior/posterior chambers
Pupil:
Opening in the iris
Aqueous Humor:
Watery fluid
Secreted between cornea and lens
Provides nourishment

17. “Glaucoma”
Excessive production of aqueous humor causes pressure on the blood supply from the optic nerve which deprives cells of oxygen causing them to die and the patient to become blind.

18. Inner Layer Retina: Optic Disc: (“Blind Spot”) Vitreous Body:
Contains photoreceptors
Optic Disc: (“Blind Spot”)
Contains nerve fibers
Contains central arteries and veins
Lacks receptors
Vitreous Body:
Maintains shape
Nourishes the posterior cavity

19. “Floaters”
Bits of vitreous humor clump and cast shadows on the retina which causes “floaters”. They can be seen most commonly when looking at the sky or a blank wall. Do YOU have floaters?

20. Visual Receptors The eye contains modified receptors in the retina
Rods: black and white
Cones: color (3 types)

21. “Color Blindness”
The person usually lacks one of the 3 types of cone receptors causing them to have trouble distinguishing reds and greens.

22. “Night Blindness”
A deficiency in Vitamin A reduces production of retinal pigments which are necessary for rod sensitivity and seeing at night.

23. Lab- Cow Eye Dissection
Gather all materials necessary for the dissection.
YOU MUST WEAR GOGGLES, AN APRON, AND GLOVES!!!!
Complete the dissection as instructed in the lab handout and be sure to show me the pinned structures for points!