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93 Cards in this Set
- Front
- Back
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Name a Potential Space in the Eye
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Between the supraciliaris and the sclera
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What is the anterior surface of the iris?
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The anterior border layer, NOT the anterior epithelium
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What kind of cell is found in the iris stroma, but not the Anterior Border layer
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Clump cells
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What gives the posterior iris epithelium color?
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pigmented columnar cells
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What produces AH?
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the outer pigmented epithelium of the ciliary body
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AH composition
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98.2% H2O
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AH pH
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6.5-7.6
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AH volume
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7.4 uL
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Lipid Layer MP
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35* C
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lipid layer thickness
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.1 um
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Most abundant NP lipid
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wax esters
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Most abundant Polar lipid
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phosphatidyl choline/ethanolamine
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What accessory glands are more abundant
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Krause > Wolfring
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What buffers tear pH
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electrolytes
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What Ab are most abundant?
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IgA, IgE
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What tearfilm proteins are antifungal
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lipocalins
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Growth Factors are important for what process?
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Healing of epithelium
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What helps up mucin layer production
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restasis
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1,4 mucins are what?
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membrane associated mucins
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5,7 mucins are what?
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secreted mucins
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What causes mucin dysfunction
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Avitaminosis A, conj destruction
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What can cause mucin excess
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hyperthyroidism, allergies
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What stimulates tear secretion
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androgen
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Main dry eye drug?
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restasis
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How many layers in corneal epithelium
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6
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how may layers in corneal endothelium
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1
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What are good reasons to test corneal sensitivty?
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Herpes or LASIK
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What innervates the cornea?
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CN V1 --> long posterior ciliary nerve
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What is the cornea's main food
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glucose
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Wha type of glucose transporter provides glucose to the cornea?
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Glut 1
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What is the difference between ATP yield % vs glucose pathway %?
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Even though more glucose goes through anaerobic pathways, the higher yield of aerobic pathways provides the majority of the ATP
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what % of glucose comes from AH?
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90%
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What is collagen type 4
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found in all basement membranes
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Where is type 2 collagen found?
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In cartilage, vitreous, BV, it is most abundant
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Where is type 1 collagen found?
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stroma
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What is Reese Buckler Corneal Dystrophy?
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A problem with Bowman's Layer
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GAG's are good for?
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Lubrication, Hydration, Migration
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What are the common suffixes of proteoglycans?
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lumiCAN, keratoCAN, mimeCAN
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What are MMPs?
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Matrix Metalloproteinases; family of Zn dependent enzymes, only MMP2 is found in healthy cornea.
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What are MMP functions?
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Balances extracellular matrix especially in stroma
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What are TIMPs?
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They are MMP antagonists
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Where is TIMP2 found?
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In the stroma to balance MMP2
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What is the difference between degeneration and dystrophy of the cornea
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Degradation = age; dystrophy = bilateral, younger, genetic, no systemic cause
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What problem can occur regarding Descemet's membrane with corneal swelling?
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Vogt's Striae, a wrinkling of Descemet's membrane.
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Fuchs' Dystrophy is a degeneration of what part of the cornea?
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Endothelium, resulting in corneal edema.
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Between Aquaporin 1 and Aquaporin 5, which one will you find in the epithelium vs the endothelium?
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Aquaporin 5 = Epithelium, Aquaporin 1 = Endothelium
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When is the only time you will find Type I collagen in the endothelium?
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After injury, fibroblastic cells express this. Normal corneal endothelium has no Type I collagen.
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What are the two theories to corneal transparency? Who made them up and which one are we siding with?
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Maurice = destructive interference, thin cornea also helps, Smith = small size fibriles. We're siding with both.
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K is what % water?
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80%
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What can cause edematous cornea to lose transparency?
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regions of disrupted fibril distribution
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Stem cells along limbus facilitate what?
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Fast healing of the epithelium
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What is the main type of cell in the corneal stroma?
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keratocytes
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What can keratocytes in the cornea do?
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Turn into fibroblasts, which can then turn into myofibroblasts
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Can myofibroblasts move?
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No, they are stationary
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Do myofibroblasts stay after wound healing?
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No
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What do myofibroblasts do?
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Produce contractile fibers that close wound
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What side effects can myofibrils cause after healing a wound?
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Haze
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Low levels of immunal activity helps maintain what?
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Clarity. Immune rxn's would release WBC into AH, etc.
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What is the master regulator of immune response in the eye?
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Interleukin 1
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What is a Hudson-Stahli line?
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Iron deposit after age 50
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What is a Kayser-Fleischer Ring?
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A copper ring in the cornea periphery associated w/ Wilson dx
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What is a Fleischer ring?
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Iron around an abnormal cone, keratoconus
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What are a few tear film anti-oxidants?
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Mucins, superoxide dismutase, ascorbic acid, glutathione
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What is the most common glaucoma in US?
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Open angle, more prevalent in blacks
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What are the major reasons for the blood-aqueous barrier?
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Tight junctions between NPE cells
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What is a syncytium?
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Continuous cytoplasm of matrixed epithelial cells connected by gap junctions
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Is there Ca++ in the AH?
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NO
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What is the major driving force of AH production?>
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Chloride
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How do CAI's lower AH?
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We don't know
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What helps water leave the NPE to form AH?
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Sodium cations
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What does glutathione do?
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Prevents disulfide bond
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What does urea do in AH?
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Stabilizes concentration gradient
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What concentration is inositol found in?
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10x higher in AH than blood plasma
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How does CO2 leave the eye?
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Through the cornea --> atmosphere
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How much CO2 comes from the lens?
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About 3%
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Transferrin does what?
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Binds iron
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Most common time to see cells and flare?
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Post cataract surgery
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What is the most important protein in the AH?
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albumin, most common
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What happens to lysozyme production in AH during inflammation?
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Concentration goes up 10 fold
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What can cause iris neovascularization
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diabetes, Graves, Dry Eye (odd)
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How much O2 is in AH vs plasma
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AH = 1/2 plasma O2 level
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How much ascorbate is in AH?
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Excessive amounts
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What can high IOP cause?
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mechanical stress
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What kind of strain is induced in the eye by high mechanical stress?
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death of the nerve fiber layer
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What sleep related substance MAY have an impact on IOP?
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melatonin
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Is it better to have a thick or thin cornea?
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Thick is more stabile IOP
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What drug reduces IOP by targeting the Cl-/HCO3- antiport
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timolol
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Alpha 2 receptors are found where?
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In presynaptic cleft, so they inhibit AH
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What is NOT the first choice for acute angle closure?
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PG drugs because they are slow acting
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What is a contraindication for PG use in the eye?
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Uveitis
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What is myocilin
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Linked to open angle glaucoma after genetic mutation
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optineurin?
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Gene associated with glaucoma
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What do glucocorticoids do to the trabecular meshwork?
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Target the expression of genes in the TIM, reorganize actin cytoskeleton, which raises IOP
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