anatomy and physiology of layers of the eye

coats of the eye

1. Physiological anatomy of the eye The eyeball The crystalline lens The fluid system of the eye

2. http://everlastingelephants.blogspot.com/2009/08/what-is-eye-cataract.html The eyeball

3. Outer fibrous layer Sclera Dense fibrous connective tissue Protective Attachement to extra-ocular muscles Cornea Transparent Light entrance Layers of the Eye Outer fibrous layer Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

4. The cornea

5. Refraction of light. 2/3 of the of the refractive power of the eye 43 diopters Protection: germs, dusts and UV light. Functions of the cornea

6. Eyelids Precorneal film of tears Protective Nutritive lubrication Corneal reflex Pathway function How the cornea protects itself

7. Pathway Functions: Protection Testing the integrity of 5 th and 7 th nerves. Stage of anaesthesia Corneal reflex

8. Regular arrangement The cornea does not have blood vessels. It gets oxygen directly through the air. It receives nutrients via : -diffusion from the tear fluid and the aqueous humour. Unmyelinated nerve endings. relative dehydration : If the corneal tissue becomes hydrated the tissue becomes opaque. metabolic pump Osmotic pump Why the cornea is clear?

9. Irregular connective tissue lamellae. Function Protection Gives attachment to E.O.M The sclera

10. Iris Boundary between anterior and posterior chambers Central hole (pupil) Ciliary body Ciliary muscle and ciliary process Attachment of suspensory ligaments Choroid Highly vascular Middle vascular layer Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

11. Functions of the Vascular layer Provide a route for blood vessels Control amount of light entering eye Adjust diameter of pupil Secrete and absorb aqueous humor Adjust lens shape for focusing Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

12. Outer pigmented part Absorbs stray light Inner neural part Detects light Processes image Communicates with brain Inner nervous layer ( Retina ) Copyright © 2007 Pearson Education, Inc., publishing as Benjamin Cummings

13. Retina: Acts like the film in a camera to create an image Consists of a specialized layer of cells Converts light signals into nerve signal then send these signals to the optic nerve Optic nerve carries the signals to the brain The brain helps process the image Rods- low light situations Cones- allows you to see color Inner nervous coat

14. A bundle of 1 million nerve fibers Responsible for transmitting nerve signals from the eye to the brain The optic disc is the front surface of the optic nerve The optic disc is visible on the retina http://cssd.us/body.cfm?id=802 Optic Nerve http :/ www.wollongong.youronlinecommunity.com.au/wollongong-online/2008/50/walkthrulife/eye-health.html

15. 17 Lens Transparent Biconvex Lies behind iris Largely composed of lens fibers Elastic Held in place by suspensory ligaments of ciliary body Conjunctiva Iris Lens Ciliary process Ciliary muscles Sclera Cornea Anterior chamber Vitreous humor Suspensory ligaments Posterior chamber Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Ciliary body