Exam 1 Koh- Cornea Biochem 1 Flashcards Preview

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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

What are the cellular components of Bowman's layer?

Type I and V collagen and glycoproteins