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