Conjunctiva - Layers, Function, Innervation (M2) Flashcards
what are the layers of the conjunctiva
surface layer of non-keratinized epithelial cells over a deeper layer of connective tissue
what is the epithelial layer composed of
non-keratinized epithelial cells, goblet cells, melanocytes, langerhans cells, lymphocytes
what is the most abundant cell type in the conjunctival epithelium
non-keratinized epithelial cells
what mostly makes up the epithelial cells
stratified columnar cells - stratified squamous cells at mucocutaneous junction and limbus
where are microvilli present in the epithelial cells
present at apex of surface cells to help bind mucin to conjunctival surface
what do non-keratinized epithelial cells secrete
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
what do goblet cells secrete
gel-forming mucins (glycoproteins)
where are goblet cells concentrated
nasal and inferior nasal region of conjunctiva
function of melanocytes
produce melanin (pigment)
filter UV radiation
function of langerhans cells
wbc.
protect against pathogens
function of lymphocytes
wbc
protect against pathogens.
what is the stromal layer (substantia propria) composed of
loose connective tissue
what is the stromal layer divided into
outer lymphoid layer and deep fibrous layer
what does the outer lymphoid layer contain
lymphocytes and plasma cells
- types of wbcs
- protect eye against pathogens
what does the deep fibrous layer contain
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
what does the conjunctiva play a role in
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
what does the conjunctiva ensure
smooth movement of eyelids over globe
- goblet cells produce mucus with major component being mucin
what nerves innervate lower conjunctiva
infratrochlear nerve (CN5 V1).
Infraorbital nerve (CN5 V2).
what nerves innervate upper conjunctiva
Infratrochlear nerve (CN5 V1).
Supraorbital nerve (CN5 V1).
Supratrochlear nerve (CN5 V1).
Lacrimal nerve (CN5 V1)
what nerves innervate bulbar conjunctiva
Long ciliary nerve (from the nasociliary nerve of the ophthalmic nerve)
