2. HISTOLOGY OF EYE
Dr Iram Tassaduq

5. EPITHELIUM Stratified squamous non keratinized Consist of 5-6 layer
Active mitosis
Turnover time for cells is 6-7 days
Extremely sensitive to touch

6. BOWMANS MEMBRANE Consists of collagen fibers
Acellular clear membrane lie under the epithelium
Cannot be regenerated if destroyed
Provides strength to cornea
Acts as a barrier against spread of infections

7. CORNEAL STROMA
Many layers of collagen bundles run parallel to each other and parallel to the surface of the cornea making the cornea transparent,
Avascular structure
Nuclei of fibroblasts
90% of corneal thickness

8. DESCEMENTS MEMBRANE Fine collagenous filaments 5-10 micrometer thick
Regenerates quickly

9. ENDOTHELIUM Single layer of flat hexagonal cells with no mitosis
Pumps water out
prevent corneal edema opacification
Maintain corneal transparency

11. LENS Capsule Refractile and formed of type IV collagen
Sub capsular epithelium
Single layer of cuboidal epithelium present on anterior surface
Lens fibers
Highly differentiatedcells

12. LENS FIBERS
Form the body of the lens. located deep to the subcapsular epithelium.
Nucleated in the soft, outer cortex of the lens. As new lens fibres are added to the periphery of the cortex, lens fibres located deeper in the cortex loose their nuclei .
Cytoplasm filled with cystalline proteins. These proteins are responsible for the transparency .

13. RETINA Innermost layer of eye ball
Develops from double walled optic cup
Outer layer forms pigment epithelium
Inner layer forms neural retina

14. RETINA The retina is the site of sensory transduction
The retina is nervous tissue composed of 6 major types of neurons and one special type of glial-like cell (the Muller cell) 
The organization of the retina is based on a three neuron chain (photoreceptor cell to bipolar cell to ganglion cell)

15. MAJOR RETINAL CELLS RODS Thin elongated cells
Composed of inner and outer segments
120 million photoreceptor cells called rods (responsible for peripheral and dim light vision)
Contain rhodopsin

16. MAJOR RETINAL CELLS CONES Lesser in number than rods
Responsible for providing central, bright light, fine detail, and color vision
Contain visual pigment
iodopsin

17. MAJOR RETINAL CELLS
Horizontal cells - interconnect groups of photoreceptor cells
Bipolar cells - interconnect photoreceptor cells with ganglion cells
Amacrine cells interconnect groups of ganglion cells and bipolar cells
Ganglion cells possess long axons that extend through the nerve fiber layer of the retina and then come together to form the optic nerve

19. LAYERS OF RETINA Pigment epithelium The layer of rods and cones
External limiting membrane.
The outer nuclear layer
Outer plexiform layer
Inner nuclear layer.
The internal plexiform layer
Ganglion cell layer.
Layer of optic nerve fibers
The internal limiting membrane

21. PIGMENT EPITHELIUM Consist of columnar cells Absorbs light
Synthesizes melanin granules
Vitamin A esterification
Cells have phagocytic proprties

22. LAYER OF RODS AND CONES

23. EXTERNAL LIMITING MEMBRANE
Not a true membrane
Formed of row of zonula adherens between muller cells and rods and cones

24. OUTER NUCLEAR LAYER

25. OUTER PLEXIFORM LAYER
Formed by the processes of photoreceptor cells and retinal neuronal cells that is horizontal bipolar and amacrine cells

26. INNER NUCLEAR LAYER
Consist of nuclei of bipolar,amacrine,horizontal and muller cells

27. INTERNAL PLEXIFORM LAYER
Formed of complex intermingled nerve cell prosesses

28. GANGLION CELL LAYER
Consist of cell bodies of large multipolar neurons

29. OPTIC NERVE LAYER
Consist of axons of ganglion cells

30. INTERNAL LIMITING MEMBRANE