ANATOMY & HISTOLOGY OF CONJUNCTIVA

ANATOMY & HISTOLOGY OF CONJUNCTIVA
BY
RAIN HEALTH CARE

1. ANATOMY of CONJUNCTIVA

2. WHAT IS? IT is a translucent mucous membrane which lines the posterior surface of the eyelids & anterior aspect of eyeball. The normal conjunctiva is- pink Smooth Thin Transparent There are normally large deep blood vesells that run vertically.

3. FUNCTION OF CONJUNCTIVA The conjunctiva helps lubricate the eye by producing mucus and tears, although a smaller volume of tears than the lacrimal gland. It also contributes to immune surveillance and helps to prevent the entrance of microbes into the eye.

4. PLAPEBRAL CONJUNCTIVA It is richly vascular, extremely thin and strongly bounded to the tarsal plate. It is subdivided into 3 parts- Marginal Tarsal orbital

5. A. MARGINAL Extends from the lid margin to about 2 mm back of the lid upto the sulcus subtarsalis . Actually a transitional zone between skin & the conjunctiva proper. Lacrimal puncta open in the marginal zone.

6. B. TARSAL Thin , transparent & highly vascular Firmly adherent to the whole tarsal plate in the upper lid and only to half width of the tarsus in the lower lid. The tarsal glands are seen through it as yellow streaks.

7. C. ORBITAL It lies loose between the tarsal plate & the fornix. Orbital margin of the upper eyelid is loose and lies over the muller’s muscle.

8. BULBAR CONJUNCTIVA It is transparent and lies loose over the underlying structures and thus can be moved easily. It is separated from the anterior sclera by episcleral tissue & tenon’s capsule. The average thickness is 33 microns It is also known as ocular conjunctiva It is further of two types.- limbal, sclera

9. LIMBAL A 3mm ridge of bulbar conjunctiva around the cornea is called limbal conjunctiva. Strongly adherent to sclero -corneal junction

10. SCLERAL COVERS the eyeball above the anterior sclera & hence known as scleral conjunctiva. Thin, transparent & loosely attached to underlying sclera Separated from the sclera by episcleral vessels and tenon’s capsule.

11. CONJUNCTIVAL FORNIX It is thin, transparent, continuous circular cui-de-sac It is broken only on the medial side by caruncle and the plica semilunaris. It joins the bulbar conjunctiva with the palpebral conjunctiva. It is further of four types- Superior Lateral Medial inferior

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13. HISTOLOGY OF CONJUNCTIVA

14. STRUCTURE OF CONJUNCTIVA Histologically cornea consists of 3 layers Epithelium Adenoid layer Fibrous layer

15. EPITHELIUM The layers of epithelial cells in the conjunctiva vary from region to region and its different parts are MARGINAL CONJUNCTIVA :- have 5layers non-keratinised stratified squamous type of epithelium. Superficial layer- squamous cells Intermediate 3 layers- polyhedral cells. Deepest layer- globlet cells.

16. TARSAL CONJUNCTIVA- Has 2 layers epithelium in the upper eyelid. Superficial layer-cylindrical cells. Deep layers- cubical cells Lower tarsal conjunctiva is made of 3-4 layers of cells like the cubical, polygonal, elongated wedge shaped and cone shaped cells. FORNIX & BULBAR CONJUCTIVA- 3 layered epithelium Superficial layer-cylindrical cells Middle layer- polyhedral cells Deep layer- cuboidal cells

17. LIMBAL CONJUNCTIVA 8-10 LAYERS of stratified squamous epithelium Most superficial 1-2 layers squamous cells. Intermediate several layers-polygonal cells. Basal layer- cylindrical or cubical cells.

18. CELL PRESENT IN THE EPITHELIUM Goblet cells Melanocytes Langerhans cells Conjunctival associated lymphoid tissue. Mucosal associated lymphoid tissue.

19. ADENOID LAYER Also called as lymphoid layer Consists of fine connective tissue reticulum in the meshes of which lie the lymphocytes Most developed in the fornices and ends at the subtarsal fold. Develops after 2-3 months of life.

20. FIBROUS LAYER Consists of a meshwork of collagenous and elastic fibres. Thicker than the adenoid layer Except in the tarsal conjunctiva where it is very thin. This layers consist vessels and nerves of the conjunctiva. The adenoid layer & the fibrous layer are collectively called as substantia propia .

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