Flashcards in Exam 1 Koh- Cornea Biochem 1 Deck (80)
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1
3 properties of the cornea?
Light transmission (transparency), protection and reparation, refractive surface
2
Cornea is composed of what 2 things?
Collagen and GAGs
3
Epithelium is ___% of total thickness
10
4
The epithelium absorbs ____ wavelength UV protection
Short
5
What are keratins?
A family of fibrous structural proteins, tough and insoluble.
6
What are some forms of keratins?
Hair, horns, nails, scales, shells
7
Glycocalyx
Filamentous material coast apical projections
8
Mucin glycoproteins
Promote tear spread and stability
9
What are sources of O2 for the open eye?
Atmosphere, tear film
10
What are sources of O2 for the closed eye?
Palpebral conj, tear film
11
What are sources of O2 with contact lenses?
Tear film, through the lens
12
What is the uptake of O2 from the epithelium?
Tear film, air
13
What is the uptake of O2 for the endothelium and posterior stroma?
From circulation via aqueous humor
14
What is the primary corneal metabolic substrate?
Glucose
15
What produces 10% of the glucose?
Preocular tear film and limbal
16
How is glucose used in the epithelium?
Passive diffusion to stroma
17
How is glucose used in the stroma?
Aqueous humor by carrier-mediated transport via endothelium
18
The endothelium makes greater use of ___ ___ than epithelium
TCA cycle
19
In the epithelium and endothelium the ___ _____ breaks down 35-65% of the glucose
HMP pathway
20
Keratocytes metabolize very little glucose via what pathway? And why?
PPP Pathway, lack 6-phosphogluconate dehydrogenase
21
How much PPP for the whole cornea?
15%
22
85% of glycolytic glucose converted to _____
Lactate
23
15% of glycolytic glucose converted to _____
Pyruvate
24
The endothelial ATP pump is ____ times as active as the epithelium
5
25
What is the most common type of ATP production between corneal epithelium and endothelium?
Anaerobic
26
Epithelium uses more ____ and endothelium uses more ____
PPP, Aerobic
27
What are the sources of glucose?
Tear film, limbal blood vessels, and aqueous
28
What percentage of glucose from the aqueous?
90
29
Where is Bowman's layer?
Posterior to the epithelial basal lamina
30
