Lacrimal Flashcards
Lacrimal excretory system
Lacrimal punctae L canaliculii L sac Nasolacrimal duct Nasal punctum (ostium)
Membrane-bound mucins
On edges of the microclimate of the epithelial cells forming glycocalyx.
Prevents pathogen pentrance and enhanced aqueous coherence.
Secretory mucins functions
Remove devis
Hold fluid in place
Bind defence molecules
Aqueous composition
💧 electrolytes glucose urea
Surface active polymers
Glycoproteins
proteins (IgA, IgG, IgG, albumin, lyzoz, lactoferrin, lipocalin, EGF, TGFS, interleukins)
Meibum composition
Wax monoesters, sterol esters
Triglycerides FFA, free sterols
Polar 🐻❄ lipids
Predisposed breeds for KCS
Westie, Cavi, Lhasa, Shih Tzu, Pug, Pekingese, E +A Cocker, English bulldog, English bull terrier, Bloodhound, Samoyed.
Qualitative tear film deficiency
Meibomianitis Goblet cell dysfunction Poor tear film distribution Lacrimal gland neoplasia Third eyelid gland neoplasia Cysts of lacrimal secretory system disease
Third eyelid gland neoplasia
Melanoma Adenocarcinoma SCC , MCT Histiocytoma, plasmocytoma Papilloma Haenigioma/sarcoma Fibrosarcoma MALT lymphoma Angiokeratoma
Complications of PDT
Failure or PDT Sialolith Sialoadenitis Blepharitis/dermatitis Calcium deposition -> Keratitis
Embryology of nl system
Ectoderm within nasolacrimal groove sink into mesenchyme below forming a cord. Cord grows towards the nose and eye forming two buds. Cord canalises (lined by pseudostratified columnar epithelium)
Tear drainage
Tear evaporation
Through nasolacrimal system : capillary action and siphon effect
Nasolacrimal drainage pathway
Blink > compression of lacrimal sac pushing tears into nasolacrimal duct> negative pressure as sac reopens> tears drawn into canaliculus
Pseudoperistalsis moves tears into nasal punctum
Nasolacrimal pathway in rabbit
Single lac punctum medial ventral conjunctival sac ,
no lacrimal sac
NL duct runs tortuous path in close proximity to caudal cheeck teeth proximaly a d incisions distal towards nasal ostuim (ventrolat)
Dacryocystitis
Inflammation of lacrimal canaliculi and sac
Causes of dacrocystitis
Obstruction (congenital amnesia, fb, inflammatory material, cystic/neo expansion, abscess)
Trauma (RTA, 🐈 scratch)
