The Lacrimal System Part 2 Flashcards
Normal tear meniscus height at lower lid margin is?
0.75mm.
Schirmer’s tear test is what type of test?
Quantitative.
What is being tested during a quantitative tear test?
Tests quantity of tears.
In Schirmer’s test, producing less than what amount of tears in 5 minutes is considered not normal?
<15 mm/5 minutes.
What is being tested during a qualitative tear test?
Tests tear film stability.
An example of an invasive qualitative test is?
Tear break up time (TBUT) with flourescein.
True or False: people who are 60 years old or older who have 10 mm of tear per 5 minutes is considered normal.
True.
An example of a noninvasive qualitative test is?
Keratometer mires (looking at cornea reflexion images)
What affects the results of the Schirmer’s test?
Placement of the strip, age, effects of anesthesia, reflex tearing, subjective measuring.
What is considered to be normal in a Schirmer’s test?
> 15 mm wetting of the paper after 5 minutes.
What is considered to be mild dry eye in a Schirmer’s test?
14-9 mm wetting of the paper after 5 minutes.
What is considered to be moderate dry eye in a Schirmer’s test?
8-4 mm wetting of the paper after 5 minutes.
What is considered to be severe in a Schirmer’s test?
<4 mm wetting of the paper after 5 minutes.
Acinar cells secrete fluid having an electrolyte composition similar to that of what?
Plasma.
Water shifts from blood into cell due to the NaK ATPase pump sending what out and what in?
Sodium out, Potassium in.
In low flow rate, the fluid is?
Hypertonic.
In high flow rate, the fluid is?
Isotonic.
Ductal cells modify fluid by secreting a fluid of higher [K] and higher [Cl] compared to plasma. This allows for what to occur?
Allow for tears to come out.
What are the nerves that innervate acinar and ductal cells?
Not quite sure but peptide and steroid hormone have a lot to do with the secretion.
What is the lacrimal gland innervated by?
Parasympathetic nerves, sympathetic nerves, sensory nerves.
Stimulations of what type of nerve results in no change in tear secretion?
Sympathetic nervous system.
What nerve is responsible for secretion and is the main contributor to tear film?
Parasympathetic fibers of CN VII.
Tear stimulation and secretion can be cause by what external factors?
Light, touch, nerves.
The mucous producing tissue that line the ocular surface is known as what?
Conjunctiva.
Normal conjunctival epithelium contains how many neutrophils and how many lymphocytes?
6,000 and 14,000.
Conjunctival reactions can be provoked by what 3 things?
Infection, inflammation, and allergies.
What type of conjunctival reaction is being described?
More commonly found in the upper eyelid, areas of conjunctival hypertrophy, contains eosinophils and neutrophils, presence of blood vessels in the center.
Papillae formation.
What type of conjunctival reaction is being described?
Clear, fluid filled pockets containing lymphocytes and macrophages, blood vessels passing either above or below but never within.
Follicle formation.
Eosinophils and neutrophils are only found in epithelium in two diseases which are what?
Vernal conjunctivitis and giant papillary conjunctivitis.
When a contact lens has dislocated from the cornea and is not visible, it is most likely located where?
Superior fornix since it has the greatest depth.
What are the two layers of the conjunctiva?
Epithelium and stroma.
At the limbus, the conjunctival epithelium is continuous with what?
Corneal epithelium.
Immediately peripheral to the limbus is a region that provides stem cells for the cornea epithelium. What is this region called?
Palisades of Vogt.
How many epithelial cell layer does the conjunctiva have and cornea have?
2-4 layers in conjunctiva epithelium and 5-7 layers in the corneal epithelium.
Palisades of Vogt have increase of what type of cells in its epithelium?
Wing cells.
Unicellular mucin-secreting glands (holocrine) within the conjunctival epithelium are what type of cells?
Goblet cells.
How wide are goblet cells?
11 microns.
Goblet cells are more frequent in what part of the conjunctiva?
Fornix and palpebral conjunctiva. Sparse in the bulba conjunctiva.
What does the stroma consist of?
Adenoid layer, deep fibrous layer, rich network of capillaries.
Where are mast cells found?
Adenoid layer of conjunctival stroma.
How many mast cells are found in conjunctiva stroma?
6,000 cells per cubic millimeter.
True or False: Mast cells, eosinophils, or basophils are found in conjunctival epithelium.
False. Normally they are not,
How big are mast cells in diameter?
20 micrometers.
The cytoplasm of the mast cells contains how many metachromatic granules?
30-100.
Mast cells are responsible for what type of reaction?
Immediate hypersensitivity reaction.
What happens when mast cells bind to IgE?
Physical properties of the mast cell change causing it to be more permeable to calcium ions, leading to edema.
Superficial posterior vessels are engorged due to what?
Infection of conjunctiva.
Deep ciliary vessels are engorged due to what?
Keratitis or iritis.
Flow of lymph is generally in _______ direction toward _______ extremes of lid, eventually connecting with ________ node.
Temporal; lateral; parotid.
Which lymph gland does the medial route of conjunctiva lead to?
Submandibular lymph gland.
