conjunctiva

what are the fxns of the conjunctiva

1. lubricates the surface of the eye

2. physical and chemical antimicrobial barrier

3. participates in diffuse lymphoid tissue system

4. provides stem cells for corneal epithelial renewal

conjunctiva characteristics

1. mucous membrane that lines the inside of the eye

   1. thin

   2. vascularized

   3. transparent

2. continuous with the skin at the margin of the eyelids —> mucocutaneous jxn

3. continuous with the corneal epithelium in the limbal region

what are the 3 regions of the conjunctiva

1. palpebral (eyelids)

2. fornices (folds on itself)

3. Bulbar (eye)

describe the palpebral conjunctiva

1. tightly bound to the tarsal plate

2. continuous with the lacrimal drainage system

describe the palpebral conjunctiva zones

1. marginal zone

   1. transition between skin of eyelid and conjunctiva

2. tarsal zone

   1. over tarsal glands (meibomian)

   2. thin

   3. immobile - tightly bound down to back of eye

   4. very vascular

3. orbital zone

   1. thin, losose, horizontal folds

describe the fornices conjunctiva

in contact w fascial sheaths of the levator palebrae superioris and recti msucles - MOBILITY OF EYE

look up and eyelid goes up

bulbar conjunctiva

1. fewer goblet cells

2. lies loosely and mobile over underlying tissue

   1. FLUID CAN ACCUMULATE

3. covers anterior 1/3 of sclera

caruncle

1. nonkeratinized stratified squamous epithelium

2. modified skin that has:

   1. fine, colorless hairs

   2. sweat and sebaceous galnd

   3. accessory lacrimal glands

3. well vascularized and innervated

11 in pic

plica semilunaris

1. fold of conjunctiva lateral to caruncle

   1. non-keratinized stratified squamous epithelium

   2. contains goblet cells

   3. highly vascularized

conjunctiva epithelium

1. non keratinized stratified

   1. squamous - limbus, palpebral close to lid margin

   2. cuboidal - bulbar

   3. columnar - palpebral and fornices

specializations of conjunctiva epithelium

1. microvilli w glycocalyx

   1. like cornea - helps to hold mucus layer of tears to surface of eye

2. surface cells joined by junctional complex

   1. like cornea

what connects the conjunctiva epithelium to a basement membrane

hemidesmosomes

like we saw in cornea

where is the limbal conjunctiva

1. right next to edge of cornea

what is unique about the limbal conjunctiva

1. Contains epithelial stem cells that replenish the corneal epithelium

2. few or no goblet cells

what is the Palisades of Vogt and where is it

1. in limbal conjunctiva

   1. radially oriented channels (papillae) within stroma of limbal conjunctiva

      1. separated from each other by ridges of epithelium (rete pegs)

   2. irregular connection between epithelial cells and underlying connective tissue

what are palisades

papillae - connective tissue

rete pegs - epithelium

irregular connection between epithelial cells and underlying connective tissue

epithelium in fornices

1. basal epithelium more columnar

2. numerous goblet cells forming pseudo glands of Henle

goblet cells fxn in conjunctiva

1. secrete mucin to lubricate the surface of the eye

2. not evenly distributed on all parts of conjunctiva

   1. more at fornice

substantia propria in conjunctiva layers

1. two layers

   1. superficial lymphoid

      1. mast cells, lymphocytes, plasma cells, neutrophils

   2. deep fibrous

      1. glands of Krause

what gives the conjunctiva its anti-infectious capability

1. the make up of the two layers in the substantia propria

2. we have mast cells (histamine), lymphocytes, plasma cells, and neutrophils in those two layers

what are glands of the conjunctiva

1. Glands of Wolfring - accessory lacrimal gland

2. Gland of Krause - accessory lacrimal gland

3. Crypts of Henle - have a lot of goblet cells

what is the difference between the lateral and medial palpebral artery

ophthalmic artery - lacrimal artery - enters upper and lower eye lid to form lateral palpebral artery

directly off ophthalmic artery - medial palpebral artery

describe the blood supply in the palpebral and fornix conjunctiva

1. two papebral arterial arcades in both upper and lower eyelid

   1. peripheral arcade - medial and lateral palpebral arteries merge

      1. branch forms posterior conjunctival artery to supply bulbar conjunctiva and fornices

   2. marginal arcade - medial and lateral palpebral arteries merge

bulbar conjunctiva

1. posterior conjunctival artery

   1. proceeds toward limbus

   2. at limbus it anastomose with the Anterior conjunctival artery

2. anterior conjunctival artery

   1. branch of anterior ciliary artery

3. Together they form the superficial marginal or pericorneal plexus

describe the lymphatic drainage of the eyelids

1. drains into ½ lymph node regions

   1. lateral - preauricular (superficial parotid) noes

      1. in front of the ear

      2. lateral 2/3 of upper lid

      3. lateral 1/3 of lower lid

   2. medial - submandibular nodes

      1. under jaw

      2. medial 1/3 of upper lid

      3. medial 2/3 of lower lid

describe the innervation of the conjunctiva

1. superior palpebral and fornix

   1. frontal and lacrimal branches of ophthalmic division of trigeminal nerve V1

2. inferior palpebral and fornix

   1. lateral: lacrimal branch of V1

   2. Medial infraorbital nerve of maxillary division of trigeminal nerve V2

what is the sensory innervation for the bulbar conjunctiva

long posterior ciliary nerves - Nasociliary N-V1