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Ocular Physiology #2 > Optic Nerve > Flashcards

Flashcards in Optic Nerve Deck (58)
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1

what are the 4 parts that the optic nerve head is divided into

surface nerve fiber layer, prelaminar region, lamina cribrosa region, and retrolaminar

2

what is the surface nerve fiber layer

the inner most portion, mostly nerve fibers

3

what is the prelaminar region

also called the anterior portion of lamina cribrosa, mostly nerve axons and astrocytes with significant increase in astroglial tissue

4

what is the lamina cribrosa region made out of

fenestrated sheets of scleral connective tissue

5

what cells line the sheets and holes of the lamina cribrosa

astrocytes

6

what passes through the holes of the lamina cribrosa

bundles of axons

7

what happens in the retrolaminar region

decrease in astrocytes and myelin is acquired around the axons

8

what is the posterior limit of the retrolaminar region

not clear, but about 3-4mm

9

what is the main arterial supply to the optic nerve

posterior ciliary artery

10

what is the arterial supply to the nerve fiber layer

retinal circulation

11

what blood vessels supply the surface of the nerve fiber layer

arteriolar branches of central retinal artery

12

what do the arteriorlar branches of the central retinal artery of the surface nerve fiber layer anasthamose with

the vessels of the prelaminar region

13

what is the blood vessel supply to prelaminar and laminar regions

short posterior ciliary arteries

14

what do the short posterior ciliary arteries of the prelaminar and laminar regions form

the circle of Zinn-Haller

15

besides suppling the prelaminar and laminar regions, what else does the circle of Zinn-Haller supply

the peripapillary choroid

16

what is the blood supply to the retrolaminar region

medial and lateral perioptic nerve short posterior ciliary arteries

17

what do the medial and lateral perioptic nerve short posterior ciliary arteries form around the optic nerve

an elliptical arterial circle- also called Zinn-Haller

18

do the capillaries increase or decrease in number posterior to the lamina

decrease

19

name the 6 blood vessel supplies to the optic nerve

1. central retinal artery 2. radial peripapillary capillaries 3. pial vessels 4. short posterior ciliary arteries 5. peripapillary choroidal vessels 6. Circle of Zinn-Haller

20

where are the capillaries of the optic nerve derived from

both retinal and ciliary circulation

21

what is the venous drainage for the optic nerve

all through the central retinal vein

22

what does the astroglial support do

provides continuous layer between nerve fiber and blood vessels of optic nerve head

23

what do the thin astrocytes do

accompany the axons in the nerve fiber layer

24

what do the thick astrocytes do

direct axons from prelaminar to laminar region

25

what happens at the lamina cribrosa during glaucoma

glaucoma pathogenesis takes place here

26

what is the lamina cribrosa an extension of

the sclera- porous region

27

what is the lamina cribrosa made of

specialized extracellular matrix- fenestrated sheets of connective tissue and occasional elastic fibers

28

What is found surrounding the myelin sheaths in the lamina cribrosa

hyaluronate

29

when does hyaluronate decreases in the lamina cribrosa

with age and an increase in IOP

30

what would cause the lamina cribrosa pores to compress

Glaucoma and high myopia