Conjunctiva - Layers, Function, Innervation (M2)

Question 1

what are the layers of the conjunctiva

Answer 1

surface layer of non-keratinized epithelial cells over a deeper layer of connective tissue

Question 2

what is the epithelial layer composed of

Answer 2

non-keratinized epithelial cells, goblet cells, melanocytes, langerhans cells, lymphocytes

Question 3

what is the most abundant cell type in the conjunctival epithelium

Answer 3

non-keratinized epithelial cells

Question 4

what mostly makes up the epithelial cells

Answer 4

stratified columnar cells - stratified squamous cells at mucocutaneous junction and limbus

Question 5

where are microvilli present in the epithelial cells

Answer 5

present at apex of surface cells to help bind mucin to conjunctival surface

Question 6

what do non-keratinized epithelial cells secrete

Answer 6

glycocalyx from the apex of surface cells:
- consists of transmembrane mucins (glycoproteins) - MUC1, MUC4, MUC16.
- barrier to pathogens and injury
- bind mucin to conjunctival surface
- spread tear film across conjunctival surface

Question 7

what do goblet cells secrete

Answer 7

gel-forming mucins (glycoproteins)

Question 8

where are goblet cells concentrated

Answer 8

nasal and inferior nasal region of conjunctiva

Question 9

function of melanocytes

Answer 9

produce melanin (pigment)
filter UV radiation

Question 10

function of langerhans cells

Answer 10

wbc.
protect against pathogens

Question 11

function of lymphocytes

Answer 11

wbc
protect against pathogens.

Question 12

what is the stromal layer (substantia propria) composed of

Answer 12

loose connective tissue

Question 13

what is the stromal layer divided into

Answer 13

outer lymphoid layer and deep fibrous layer

Question 14

what does the outer lymphoid layer contain

Answer 14

lymphocytes and plasma cells
- types of wbcs
- protect eye against pathogens

Question 15

what does the deep fibrous layer contain

Answer 15

accessory lacrimal glands
- produce aqueous component of tear film
- accessory lacrimal glands of Krause are in forniceal conjunctiva
- accessory lacrimal glands of Wolfring are in palpebral conjunctiva.
rich in blood vessels, lymphatic vessels, and nerves

Question 16

what does the conjunctiva play a role in

Answer 16

immunological defense system of the ocular surface:
- particulates and pathogens become trapped in mucus - preventing entry into deeper tissues.
- epithelial and stromal layers contain wbcs
- glycocalyx provides barrier against pathogens

Question 17

what does the conjunctiva ensure

Answer 17

smooth movement of eyelids over globe
- goblet cells produce mucus with major component being mucin

Question 18

what nerves innervate lower conjunctiva

Answer 18

infratrochlear nerve (CN5 V1).
Infraorbital nerve (CN5 V2).

Question 19

what nerves innervate upper conjunctiva

Answer 19

Infratrochlear nerve (CN5 V1).
Supraorbital nerve (CN5 V1).
Supratrochlear nerve (CN5 V1).
Lacrimal nerve (CN5 V1)

Question 20

what nerves innervate bulbar conjunctiva

Answer 20

Long ciliary nerve (from the nasociliary nerve of the ophthalmic nerve)