Exam 2 Koh- Retina Biochem 4 Flashcards Preview

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Flashcards in Exam 2 Koh- Retina Biochem 4 Deck (86)
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1

What is important to RPE function?

Proteins, lipids, and nucleic acids

2

____% of wet weight of the retina is water

>80

3

What is the primary carbon source used for energy?

Glucose

4

Glucose is not converted to _______ in the RPE

Glycogen

5

Nearly ______ proteins have been identified in RPE

850

6

What gene is RPE specific

RPE 65

7

______ compose of ~3% of the wet weight of the RPE

Lipids

8

______% of wet weight are phospholipids with PC and PE

5

9

Higher saturated FAs in the RPE include what?

Palmitic/stearic acid

10

About 1% of the wet weight of the RPE is contributed by _____

RNA

11

Retinal pigment epithelium is a single layer of cells with what type of junction?

Tight

12

The RPE is a single layer of _____ epithelial cells

Columnar

13

Where is the outermost layer of the retina located?

Between the choroid and outer segments

14

How many RPE cells per eye?

4-6 million

15

What is the ratio of photoreceptor cells to RPE cells?

45:1

16

Epithelial cells are polarized with long ____ microvillous processes interdigitating the outer segment, and____ aspects adjacent to Bruch's membrane

Apical, basal

17

What serves as a blood-retinal barrier?

Polarized cells in the RPE

18

What are the retinal pigment epithelium functions?

Light absorption, epithelial transport, glia, visual cycle, phagocytosis, secretion

19

How does the RPE increase optical quality?

Forming a dark pigmented wall, aids in absorption of scattered light

20

Blood perfusion of the choriocapillaris is ____ than the kidney

Higher

21

Venous blood from the choriocapillaris shows ___% O2 saturation

90

22

By comparison, venous blood from retinal vessels shows a O2 saturation of ____%

45

23

What is OCA?

Oculocutaneous albinism

24

OCA1 and OCA2 are due to defects in what?

The tyrosinase gene and the pink-eyed dilution gene

25

What happens when melanin levels are below a critical level?

Lack of foveal development, low vision, nystagmus and stabismus

26

What is the RPEs 3 lines of defense against toxins?

Light absorption, antioxidants and repairment

27

There is absorption and filtering of light via melanin in ________

Melanosomes

28

There is additional light absorption in the RPE by what 3 things?

Carotenoids, lutein, and zeaxanthin

29

What does blue light do in the RPE?

Permits the photoxidation of lipofuscin components to cell toxic substances

30

Lipofuscin ______ in the RPE during life

Accumulates