ppt of eye

Schematic horizontal meridional section of right eye

Optic nerve
Dura
Med. rectus
Ora serrata
Zonula ciliaris
Lamina cribrosa
Fovea
Retina
Choroid
Sclera
Lat. rectus
Ciliary muscle
Limbus
Posterior chamber
Canal of Schelemn
Conjunctiva
Cornea
Anterior
Chamber iris
V.A.
A.P.
P.P.
Vitreous
Ciliary body
Lens


ORGAN OF VISION
Eyeball
Accessory Structure (Adnexa)
Layers
Fills
T.Fibrosa (External Layer)
T.Vasculosa (Middle Layer)
T. Nervosa (inner Layer)
Sclera
Cornea
Choroid
Ciliary Body
Iris
Retina
Lens
Anterior Chamber
Posterior Chamber
Vitreous Body
Eye Lids
Tears Gland
Muscles

TUNICA FIBROSA

OpaqueWhitePosterior five sixth of the external layerConsists of:Flat Collagen BundlesGround SubstanceFibroblastsEpisclera, Tenon’s Space, Tenon’s capsuleSuprachoroidal lamina SCLERA


TransparentColorlessAnterior one sixth of the external layerConsists of 5 layers:Layer of epitheliumBowman’s membraneSubstantia PropriaDescement’s membraneEndothelium Avasculer structure, receives its metabolizes by: diffusion from adjacent vessel and from fluid of the anterior chamber
CORNEA


Photomicrographs of a transverse section of cornea. A : The Cornea and conjuctiva seen at low magnification. B : The posterior corneal epithelium – also called endothelium (arrows indicate Descemet’s membrane). C : Conjuntival epithelium. D : Anterior corneal epithelium. Note the smooth contour of the surface of this epithelium. A
B
C
D
Conjunctiva


Layers of epithelium: Stratified squamos epithelium 5-6 cells layers Deepest : columnar Next : polyhydral Surface : flat in shape
Bowman’s membrane: A thin layer Appears homogenous Structureless under the light microscope

Substantia propria 90% of the thickness Composed: Collagenous fibrils arranged in lamellae (parallel with the surface) Mucoid cement Cells
Descement’s membrane: Appears homogenous Fibrous protein of collagen type Endothelium: Single layers of cells Low cuboidal epithelium



Area of transition from transparent collagen bundles of the cornea to the white opaque fibers of the scleraThe corneal epithelium, as it passes over into the limbus, increases in thickness up to ten or more cellsThe corneal stroma losses its regular lamellar arrangementIn the stromal layer, irregular endothelium – lined channels, the trabecular mesh work, merge to form the canal of Schlemm LIMBUS (Corneoscleral Junction)


Diagram of the right eye, seen from above, showing the structure of the eye, retina, fovea and ciliary body. Arrows in the anterior chamber show the direction of flow of aqueous humor. An enlarged diagram of the fovea is shown at lower right. Axons of ganglion cells Bipolar cells Rods Cones
Sclera
Limbus
Cornea
Canal of schlemm
Lens
Iris
Zonule
Ora serrata
Posterior chamber
Ciliary body and process
Choroid
Anterior chamber
Vitreous body
Photosensitive retina
Optic papilla
Fovea
Sclera
Pigment epithelium
Choroid
Optic nerve
Ciliary muscles
Sclera


Divided into four layers: The Suprachoroid, lamina suprachoroidea or epichoroid Consist of lamellae, each lamella: very thin membrane Vessel layer (stratum vasculosa) Outer layer : large vessels Inner layer : medium sized vessels
TUNICA VASCULOSA
A. CHOROID


3. The capillary layer (Lamina Choriocapillaris). Serves of nutrition for the outer layers of the retina 4. The lamina Vitrea, lamina elastica / basalis, or membrane of Bruch: Non cellular membrane Two layers: The outer elastic lamellae, very thin The inner cuticle lamellae, relatively thicker


1
2
3
4
5
6
7
8
9
10
11
12
13
14
Sc.
Ch.
Ret.
Section through retina, choroid and sclera.
Ch = Choroid; Ret = Retina; 1 = Suprachoroid; 2 = Vessel layer; 3 = choriocapillaris 4 = Lamina vitrea 5 = Pigment epithelium 6 = layer of rods and cones 7 = external limiting membrane 8 = outer nuclear layer 9 = outer plexiform layer 10 = inner nuclear layer 11 = inner plexiform 12 = ganglion cell layer 13 = nerve fiber layer 14 = internal limiting membrane



Two zones: The orbiculus ciliaris (Pars Plana) The posterior two thirds Appears darkly pigmented Relatively smooth The corona ciliaris (Pars Plicata) The anterior third Bears some 70 to 80 radially arranged ridges, the ciliary processes
B. CILIARY BODY


Ora serrata, ciliary body, zonula ciliaris and lens as viewed from behind after removal of the vitreous body
Circumlental space
Ciliary processes
Ora serrata
Orbiculus ciliaris
Lens
Zonula fibers

A thin circular diapraghma A circular aperture: the pupil Divides the space between the cornea and the lens into two chambers: The anterior chamber The posterior chamber
IRIS

Schematic horizontal meridional section of right eye

Optic nerve
Dura
Med. rectus
Ora serrata
Zonula ciliaris
Lamina cribrosa
Fovea
Retina
Choroid
Sclera
Lat. rectus
Ciliary muscle
Limbus
Posterior chamber
Canal of schelemn
Conjunctiva
Cornea
Anterior
Chamber iris
V.A.
A.P.
P.P.
Vitreous
Ciliary body
Lens


Layer of iris is five layers:
Endothelium A very thin delicate layer Difficult to demonstrate in sections Best shown after treatment with silver nitrate


The anterior border layer The color of the iris upon: The thickness of the anterior border layer And the degree of pigmentation of it cells In the brown iris: The layer is thick The cells heavily pigmented In the blue iris: The layer is thin The cells minimum amount of pigment


The vessel’s layer (stroma) - Consists of a great number of blood vesselM. Sphincter pupillae: - In the pupillary zone Contraction: Reduced the diameter of the pupil - The dilatator pupillae Contraction: Dilatation of the pupilThe pigment epithelium

Pigment epithelium

Sphincter pupillae
Endothelium
Anterior border layer
Stroma
Horizontal section through pupillary zone of human iris


Consists of two portions :The posterior portion is photosensitive – pars optica retinaeThe anterior part is not photosensitive – pars coeca retinae. Constitutes the inner lining of the ciliary body and the posterior part of the iris The retina forms the pars optica retinae. The scalloped anterior border of the retina is known as the orra serrata.
TUNICA NERVOSA



Epithelium
Choroid
Sclera
Photomicrograph of a section of retina in the transition (arrow) between the photosensitive (at left) and blind (at right) parts. This transition is called the ora serrata. Note the pigment epithelium, the choroid and the sclera.


The retina consists of ten layers , except at : The fovea centralis The optic disc (optic papillae) The extreme periphery
RETINA


Diagram of the right eye, seen from above, showing the structure of the eye, retina, fovea and ciliary body. Arrows in the anterior chamber show the direction of flow of aqueous humor. An enlarged diagram of the fovea is shown at lower right. Axons of ganglion cells Bipolar cells Rods Cones
Sclera
Limbus
Cornea
Canal of schlemm
Lens
Iris
Zonule
Ora serrata
Posterior chamber
Ciliary body and process
Choroid
Anterior chamber
Vitreous body
Photosensitive retina
Optic papilla
Fovea
Sclera
Pigment epithelium
Choroid
Optic nerve
Ciliary muscles
Sclera


Development of the retina :The retina derived from an evagination of the anterior cephalic vesicle or prosencephalonAs this co-called optic vesicle comes into contact with the surface ectoderm, it gradually in vaginates in its central region forming a double – walled optic cup.In the adult :The outer wall gives rise to a thin membrane called the pigment epitheliumThe inner layer is derived the optical or functioning part of the retina

Diagrams of 4 stages in the development of the eye

Lens Vesicle

Layer of the RETINA :

Pigment epithelium Layers of rods and cones External limiting membrane Outer nuclear (or granular) layer Outer flexiform (or molecular) layer Inner nuclear (or granular) layer Inner flexiform (or molecular) layer Ganglion cell layer Nerve fiber layer Internal limiting membrane

RETINA, CHOROID AND SCLERA

4. Collagenous fibers
5. Chromatophores
6. Blood vessel
7. Pigment epithelium
8. Rods and cones
9. Outer limiting membrane
10. Outer nuclear layer
11. Outer plexiform layer
12. Inner nuclear layer
13. Inner plexiform layer
14. Ganglion cell layer
15. Nerve fiber layer
16. Inner limiting membrane
1. Sclera
2. Choroid
3. Retina


20. Processes of pigment cells extending between rods and cones
21. Cones
22. Rod
23. Outer limiting membrane
24. Nuclei of cones
25. Nuclei of rods
26. Outer processes of Muller’s cells 27. Synapses between horizontal and visual cells
28. Synapses between cones and bipolar cells
29. Bipolar cell
30. Muller’s cell 31. Amacrine cell
32. Synapses between processes of bipolar, amacrine and ganglionic cells
33. Ganglion cell
34. Fiber of optic nerve
35. Horizontal fiber
36. Inner limiting membrane
37. Inner fibers of Muller’s cells 1. Blood vessels of the choroid
2. Chromatophores
3. Pigment cells in the retina
4. Rods
5. Cones
6. Outer limiting membrane
7. Nuclei of cones
8. Nuclei of rods
9. Outer plexiform layer
10. Nuclei of bipolar, horizontal, amacrine and Muller’s cells 11. Inner plexiform layer
12. Ganglion cell layer
13. Muller’s fibers 14. Axons of ganglion cells
15. Inner limiting membrane
16. Sclera
17. Suprachoroid layer (lamina fusca)with chromatophores
18. Vascular layer of the choroid
19. Choriocapillary layer


THE ROD CELLS AND THE CONE CELLS
The rod cells : Photo pigment : Visual purple or rhodopsin Each retina has about 120 million rods Sensitive to light and the receptors used when low levels of light


The Cone cells : Photo pigment : iodopsin Each retina has about 6 million cones Sensitive only to light of a higher intensity Maximum sensitive is in the red, green or blue of the visible spectrum

Narrow collar

Outer limiting membrane (Composed of terminal bars and filaments of mueller cells)
Mueller cell cytoplasm
Discs
Outer segments
Cilium
Inner segments
Nuclei
Synapses
Processes of bipolar cells

Diagram showing the arrangement of the three layers of neurons in the retina. Observe that the light and the nervous impulses travel in opposite directions.
The light and the nervous impulses travel in the retina



Transparent Biconvex, posterior surface has a greater convesity than the anterior surface Three structural component : Lens capsule : homogenous Subcapsular Epithelium Single layer of cuboidal epithelium cells Present only on the anterior surface Lens Fibers : Appear as thin flattened structures They are highly differentiated cells derived from cells of the subcapsuler epithelium
LENS


From section through margin of lens longitudinal sections of lens fibers and transition from epithelium to lens fibers. a : Lens fibers; b: capsule; c : epithelium
The lens, viewed from behind and from the side.

The lens is held in place by the zonula ciliaris (Zonula of Zinn, suspensory ligament)

The Zonula on : The lens capsule The ciliary body
The zonula is important in process accomodation


Anterior view of the ciliary processes showing the zonules attaching of the lens. Zonule fibers are bundles of microfilaments (oxytalan fibers) from the elastic fibers system. The zonules form column (A) on either side of the ciliary processes (B), which meet on a single site (C) as they attach to the lens.
Connective tissue
Lens

Transparent gell Amorphous Intercellular substance Bounded by : The internal limiting membrane of the retina The lens The posterior zonular membrane
THE VITREOUS BODY

Accessory structures

A. EYELIDS
10. Superior tarsal muscle (of Muller)
11. Adipose tissue
12. Accessory lactrimal gland (of Krause)
13. Lymphatic tissue
14. Epithelium of palpebral conjuctiva
15. Tarsal glands (Meibomian glands)
16. Tarsus
17. Palpebral conjuctiva
18. Duct of tarsal gland (Meibomian gland)
19. Ciliary muscle (of Riolan)
20. Hair follicles of eyelashes
1. Hair follicles
2. Sweat glands
3. Epidermis and dermis
4. Rudimentary hari follicle
5. Palpebral part of orbicularis oculi muscle
6. Connective tissue
7. Arteriole
8. Ciliary glands : large sweat glands (of Moll)
9. Sebaceous glands (of Zeiss)

Consists of : The lacrimal gland Canaliculi Lacrimal sac Nasolacrimal duct

B. Lacrimal Apparatus


The Lacrimal Gland : Tear secreting gland Located in the anterior superior temporal portion of the orbit Consist of several separate glandular lobes Tubulo alveolar Serous type Myoepithelial cells surround the secretory portions

LACRIMAL GLAND

1. Glandular alveoli
2. Intralobular ducts
3. Myoepithelial cell (basal or basket cell)
4. Interlobular connective tissue
5. Outpocketing of glandular cells
6. Venule
7. Interlobular duct
8. Glandular alveoli
9. Interalveolar connective tissue
10. Arteries
11. Interlobular duct


DRAINAGE OF TEARS
Lacrimal Gland
Cornea, Bulbar and palpebral conjunctiva
Lacrimal Puncta
Lacrimal Canaliculi
Lacrimal Sac
Nasolacrimal Duct
Inferior meatus of nasal cavity

THE LACRIMAL DRAINAGE SYSTEM