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Ocular Physiology #2 > Retina > Flashcards

Flashcards in Retina Deck (99)
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1

how much of the eye is retina

extends over the posterior 2/3 of globe

2

what are the boundaries of the retina

internally bound by the vitreous and externally connected to Bruch's membrane

3

how many layers thick is the retina

10

4

what color is a normal retina

reddish because of purple rhodopsin (thin transparent membrane)

5

what happens to the retina with light exposure

bleaches

6

when does the retina turn gray/opacify

1 hr after death

7

what are the two chief retinal functions

detecting light and movement (rods) and color and form vision (cones)

8

what are rods and cones names based on

the appearance of their outer segments

9

where is the retina thinest

centrally and peripherally

10

what is the fundus oculi

the internal background of the eye, orange-red color secondary to choroid and RPE

11

what does the fundus look like in fair and darker subjects

lighter in fair and darker/grayish fundi

12

what does the fundus look like in albino patients

you can see the choroidal vessels through the retina and the white scleral tissue

13

why is the fundus of albino patients transparent

they are almost devoid of pigment (extremely photophobic)

14

where is the optic nerve located

3mm medially to and slightly above the posterior pole

15

what is the blind spot

the optic disc is devoid of photoreceptors- its projection into space produces the blind spot

16

where is the fovea centralis located

temporal to and below the posterior pole (1-2mm diameter)

17

what is the fovea centralis

retinal thinning produces a shallow depression in the surface where the nerve elements are heaped to form Henle's layer

18

what is the foveola

the 0.35mm within the fovea, only has CONES

19

what is the macula lutea

the yellow spot around the fovea centralis, yellow pigment (xanthophyll) found here

20

what are the 4 areas of the fovea centralis

foveola, fovea, parafoveal area, and periforveal area

21

what is the ora serrata

it separates the neural part of the retinal periphery from the ciliary body

22

where is the ora serrata

8.5mm behind the limbus and 6mm in front of the equator

23

where is a common spot for retinal detachments

in the ora serrata- the vitreous is firmly attached here

24

what do the arteries and veins look like in the retina

the arteries are thinner and lighter, veins are wider and darker

25

are there anastomoses in the retinal arteries and veins

no

26

what are the 4 subdivision regions of the retina

pigment epithelial layer, photoreceptor layer, intermediate cell layer, ganglion cell layer

27

what is the pigment epithelial layer (RPE) connected to

Bruch's membrane

28

what are the 5 functions of the RPE

1. absorption of light and removal of heat
2. captures excessive and stray light- projects receptors
3. provides nutrients and O2 to photoreceptors
4. reservoirs of useful substances (vitamin A)
5. phagocytotic activity of shed discs

29

does the RPE layer have mitosis

no, neighboring cells occupy space after cells die

30

how many cells is each pigment epithelium cells in contact with

up to 45 photoreceptors