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 5th and
7th nerves.
• Stage of
anaesthesia
Corneal reflex

10. 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?

11. Irregular connective tissue lamellae.
Function
•Protection
•Gives attachment to E.O.M
The sclera

12. • 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

13. • 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

14. • 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

15.  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

16. 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

17. 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