Lacrimal apparatus Flashcards
(56 cards)
what are the functions of the lacrimal gland
provide aqueous portion of tear film and lubricate the eye
which way do the tears spread on the eye
lateral to medial
where do the tears go after entering the lid margin and the canaliculi
they drain into the lacrimal sac, then into the naso-lacrimal duct, opening into the inferior meatus of the nasal cavity
where is the lacrimal gland located
superotemporally, just posterior to the supraorbital rim in a fossa of the frontal bone
which lobe of the lacrimal gland is larger?
the orbital lobe (almond shape)
how big is the palepral portion of the lacrimal gland
1/3 the size of the orbital lobe
where is the palpebral portion of the lacrimal gland located
lies underneath the aponeurosis of the levator, inferior to the orbital lobe
which lobe can be seen by gross inspection of the supratemporal fornix of the conjunctiva
the palpebral portion
the acini of the lacrimal gland are composed of what two layers
a basal myoepithelial cell layer (flat) and an inner layer of secretory columnar cells
what do the myoepithelial cells of the acini do
they contract and force secretions from the inner layer of columnar cells into the central lumen
what type of gland is the lacrimal gland
a tubuloacinar exocrine gland
what 5 things are tears composed of
proteins, electrolytes, anti-bacterial enzymes, immoglobulins, and bacterial proteins
what does blinking do to the tear film
it distributes substances, supplies oxygen to cornea, remove foreign bodies and exfoliates cells
what is the tear film comprised of
lipid or oily layer, aqueous layer, and mucus layer
what layer of the tear film is the largest
the aqueous layer
where is the mucous layer secreted
in goblet cells located in the palpebral conjunctiva
what is the purpose of the mucus layer
it is hydrophilic and decreases surface tension, provides a wettable surface for the aqueous layer
what is the arterial supply for the lacrimal gland
the lacrimal branch of the ophthalmic artery
what sensory stimuli innervates the lacrimal gland
lacrimal branch of the ophthalmic division of the trigeminal nerve (CN 5)
what nerves stimulate reflex tearing
ophthalmic division of the trigeminal nerve (afferent pathway or sensory)
where does the lymph drain for the lacrimal gland
into the conjunctival lymphatics and then into the preauricular nodes
what is the gland of Krause
an accessory lacrimal gland located in the deep subconjunctival tissue
what is the gland of Wolfring
an accessory lacrimal gland in the tarsus (inferior to gland of Krause)
what is the small elevation at the junction of the ciliary and lacrimal portions of the lid called
the papilla lacrimalis (lacrimal papilla)
