1. 4/30/2015By Dr. Rick Woodward1 April 26, 2011: Tuesday Today’s Agenda New Seating Chart A. Journal Questions: 1. Where does most nutrient absorption occur within your digestive system? 2. What is peristalsis? *B. Lecture II: Eye Anatomy & Function. Ending on Slide 26 C. Color Anatomical Structures of the Eye D. Discovery Video: Sight & Sensation E. Homework: Study for Next week’s exam: Exam on Monday: Lobes of the brain, the eye, Digestion, Absorption, and Excretion.

2. Visual Disorders: A. Myopia = Nearsightedness: (1) Individuals can only see things that are close to them. -distant objects look blurry. 4/30/2015By Dr. Rick Woodward2

3. 4/30/2015By Dr. Rick Woodward3 The Function & Anatomy of the Eye By Dr. Rick Woodward

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6. Eye Charts 4/30/2015By Dr. Rick Woodward6

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8. 4/30/2015By Dr. Rick Woodward8 Anatomy Terminology A. Anterior = Front B. Posterior = Back C. Ventral = Belly D. Dorsal = Top

9. 4/30/2015By Dr. Rick Woodward9 The Eyeball is Composed of 3 Layers: 1. Fibrous Tunic (Connective tissue) 2. Vascular Tunic (Receives blood) 3. Nervous Tunic (Retina: Receives impulses from the nervous system)

10. 4/30/2015By Dr. Rick Woodward10 The Eyeball is Composed of 3 Layers: 1. Fibrous Tunic: The outer coat of the eyeball. (1) Cornea (2) Sclera

11. 4/30/2015By Dr. Rick Woodward11 The Eyeball is Composed of 3 Layers: (1) Cornea: Anterior portion of the fibrous tunic a. Nonvascular, transparent coat which covers the pigmented iris. b. Function: Helps focus light. (Most important refracting surface of the eye.)

12. 4/30/2015By Dr. Rick Woodward12 The Eyeball is Composed of 3 Layers: (2) Sclera: Posterior portion of the fibrous tunic. a. Also called the “white” of the eye. b. Function: Gives shape to the eye.

13. 4/30/2015By Dr. Rick Woodward13 The Eyeball is Composed of 3 Layers 2. Vascular Tunic – The middle layer of the eyeball. (1) Choroid: Posterior portion of the vascular tunic. a. Provides blood supply and absorbs light rays.

14. 4/30/2015By Dr. Rick Woodward14 The Eyeball is Composed of 3 Layers (2) Ciliary Body: Anterior portion of the vascular tunic. a. Composed of two structures: (1) Ciliary Process (folds of ciliary body): Secretes aqueous humor. (2) Ciliary Muscle: Smooth muscle that alters the shape of the lens.

15. 4/30/2015By Dr. Rick Woodward15 The Eyeball is Composed of 3 Layers (3) Iris: Anterior portion of the vascular tunic. a. Pigmented doughnut-shaped structure composed of muscle fibers. b. Function: Regulates the amount of light that enters the eye. c. Pupil: Black hole in the center of the iris through which light enters the eyeball.

16. 4/30/2015By Dr. Rick Woodward16 The Eyeball is Composed of 3 Layers 3. Nervous Tunic (Retina) –The inner coat of the eyeball. a. Found only in the posterior portion of the eyeball. b. Function: Image formation. (1) Receives light and converts light into nerve impulses, it then transmits the information to the optic nerve and then to the occipital lobe of the brain

17. 4/30/2015By Dr. Rick Woodward17 The 2 Layers of the Retina: 1. Outer pigmented layer (non-visual portion) 2. Inner nervous tissue layer (visual portion) a. Contains Photoreceptors: (1) Rods (2) Cones

18. 4/30/2015By Dr. Rick Woodward18 Function of the Rods: A. Specialized for vision and dim light. B. Discrimination between different shades of dark and light. C. Allows us to see shapes and movement.

19. 4/30/2015By Dr. Rick Woodward19 Function of the Cones: A. Color vision and visual acuity (sharpness of vision)

20. 4/30/2015By Dr. Rick Woodward20 The Lens A. Located behind (posterior) the pupil and iris. B. The lens is avascular and normally transparent “Cataract = loss of transparency” C. Suspensory Ligaments hold the lens in position

21. 4/30/2015By Dr. Rick Woodward21 The Lens D. Function: Focus light rays for clear vision. E. Contact lenses work by conforming to the curvature of the cornea.

22. 4/30/2015By Dr. Rick Woodward22 The Interior of the Eyeball A. Composed of two cavities: (1) Anterior Cavity (located anterior to the lens) a. Anterior Chamber b. Posterior Chamber (2) Posterior Cavity (located between the lens and the retina)

23. 4/30/2015By Dr. Rick Woodward23 Anterior Chamber A. Located in front (anterior) of the iris and behind the cornea. (1) Filled with aqueous humor (2) Pressure is kept within normal limits by drainage of aqueous humor through the Canal of Schlemn. -Glaucoma is characterized by an increase in intraocular pressure.

24. 4/30/2015By Dr. Rick Woodward24 Posterior Cavity A. Located between the lens and the retina. B. It is a much larger cavity. C. It contains vitreous humor; which helps prevent the eyeball from collapsing.

25. 4/30/2015By Dr. Rick Woodward25 Start to Study for Your Exam It will cover: Eye, Digestion, Absorption, Excretion, Use your lecture notes, handouts, Film: Your Exam is next Monday Sheep Eye Dissection Coming up Next!