Conjunctiva

CONJUNCTIVA – ANATOMY AND PHYSIOLOGY

-AARTHY.M.R.S.

CONJUNCTIVA: It is a thin , semi transparent mucous membrane that covers the inner surface of the eyelid and the white part of the eyeball (SCLERA)

PARTS OF CONJUNCTIVA:

PALPEBRAL CONJUNCTIVAFORNICEAL CONJUNCTIVABULBAR CONJUNCTIVA

PALPEBRAL CONJUNCTIVA: Covering the lidsFirmly adherentHighly vascularExtremely thinStrongly bound to the tarsal plate

FORNICEAL CONJUNCTIVA:

Covering the lidsThrown into foldsTransitional region between palpebral and bulbar conjunvctivaSuperior fornix - 10 mm from limbusInferior fornix - 8 mm from limbusLateral fornix – 14 mm from limbusMedially absent

BULBAR CONJUNCTIVA:

Covering the eyeballThin,translucent and loosely attached to the underlying sclera by TENON’S CAPSULEConjunctival limbus 1mm anterior to corneal limbus

EPITHELIUM OF CONJUNCTIVA:The inner surface of the eyelids and the outer surface of the eyeball are lined by STRATIFIED COLUMNAR EPITHELIUM containg goblet cell which secretes mucus

At limbus,change into stratified squamous non-keratinized epitheliumAt lid margin,change into stratified squamous keratinized epitheliumPresence of accessory lacrimal glandsThe epithelial layer contains blood vessels,Fibrous tissue and lymphatic channel

BLOOD SUPPLY:

Anterior conjunctival arteries derived from the Ant.ciliary arteriesPosterior conjunctival arteries derived from theArterial arcade of lids which is formed by palpebral Branches of nasal and lacrimal arteries of lids

ARTERIAL SUPPLY:

VENOUS DRAINAGE:Palpebral and ophthalmic veins

NERVE SUPPLY:BULBAR CONJUNCTIVA:

long ciliary nerveNaso ciliary nerveOphthalmic division of trigeminal nerve

SUP.PALPEBRAL AND FORNICEAL CONJUNCTIVA:

Frontal and lacrimal branches of ophthalmic division of trigeminal nerve

INFERIOR PALPEBRAL AND FORNICEALCONJUNCTIVA:

Laterally-lacrimal branches of ophthalmic division of trigeminal nerveMedially-infraorbital nerve maxillary division of trigeminal nerve

SYMPATHETIC:Superior cervical sympatics to blood vessels

LYMPHATIC DRAINAGE:Lymph vessels are arranged as a deep anda superficial plexes in submucosa

PHYSIOLOGY OF CONJUNCTIVA:Smooth surfaceSecretes mucin and aqueous component of tear flimHighly vascular:supplies nutrition to the peripheral corneaAqueous veins drain from ant.chamber for the maintanence of IOPHelps to prevent the entry of microbes into the eye