Optic Nerve Flashcards
(70 cards)
1
Q
Name the 4 parts of the optic nerve head
A
1- surface nerve fiber layer
2-prelimar region
3-lamina cribrosa region
4-retrolaminar
2
Q
The inner most portion
- -predominantly nerve fiver
- -axonal bundle acquire more interaxonal glial tissue as this structure is followed posteriorly
--all of these describe which part of the optic nerve head? 1- surface nerve fiber layer 2-prelimar region 3-lamina cribrosa region 4-retrolaminar
A
1- surface nerve fiber layer
3
Q
- -Fenestrated sheets of scleral connective tissue
- -Astrocytes separate the sheets and line the holes
- -Bundle of axons leave through these holes
--all of these describe which part of the optic nerve head? 1- surface nerve fiber layer 2-prelimar region 3-lamina cribrosa region 4-retrolaminar
A
3-lamina cribrosa region
4
Q
- -Also called anterior portion of lamina cribrosa
- -Predominant structure: nerve axons and astrocytes with significant increase in astroglial tissue
--all of these describe which part of the optic nerve head? 1- surface nerve fiber layer 2-prelimar region 3-lamina cribrosa region 4-retrolaminar
A
2-prelimar region
5
Q
- -Decrease in astrocytes
- -Myelin is acquired
- -Axonal bundles surrounded by connective tissue
- -Posterior limit is not clear but about 3 to 4 mm
--all of these describe which part of the optic nerve head? 1- surface nerve fiber layer 2-prelimar region 3-lamina cribrosa region 4-retrolaminar
A
4-retrolaminar
6
Q
The arterial supply of the optic nerve is from the
(posterior/anterior) ciliary artery
A
posterior
7
Q
Which part of the optic nerve is not supplied by the posterior ciliary arter? 1- surface nerve fiber layer 2-prelimar region 3-lamina cribrosa region 4-retrolaminar
A
1- surface nerve fiber layer- supplied by retinal circulation
8
Q
How many blood vessels supply the optic nerve?
A
6
9
Q
- Main supply Arteriolar branches of (____)
- Anasthamose with the vessels of prelaminar region
- -all of these supply the surface of the (___)
- pick one–
- CRA central retinal artery
- RPC radial peripapillary capillaries
- PV pial vessels
- SPCA short posterior ciliary arteries
- PCV peripapillary choroidal vessels
- ZH circle of Zinn-Haller
A
-CRA central retinal artery
Nerve fiber layer
10
Q
- -blood vessel supply to the retrolaminar region
- -Medial and lateral perioptic nerve (___)
- -Form an elliptical arterial circle around the optic nerve (also called circle of ___)
A
-SPCA short posterior ciliary arteries
ZH- zinn haller
11
Q
- blood vessel supply to prelamina and laminar regions
- primary supply is (__)
- also supply peripapillary choroid
A
-SPCA short posterior ciliary arteries
12
Q
What is derived from both retinal and ciliary circulation?
A
capiillaries
13
Q
Capillaries in the optic nerve resemble capilarries in the (retina/iris/ciliary body)
A
retina
14
Q
Capillaries in the optic nerve (do/do not) leak fluroescein and may represent ____-blood barrier
A
do not
nerve
15
Q
Capillaries in the optic nerve (decrease/increase) in number posterior to lamina
A
decrease
16
Q
Venous drainage for the optic nerve is entirely through the _(central/peripheral) (choroid/retinal) ___ vein
A
central retinal
17
Q
____ support provides continuous layer between nerve fiber and blood vessels of optic nerve head
A
astroglial
18
Q
Thin astrocytes accompany the axon on (ZH/NFL/SPCA)
A
NFL
19
Q
Thick astrocytes are (indirect/direct) axons from prelaminar to laminar region
A
direct
20
Q
Glaucoma pathogenesis takes place at level of ________ _____ (two words)
A
lamina cribrosa
21
Q
The lamina cribrosa is the porous region of the (choriod/sclera/retina)
A
sclera
22
Q
the lamina cribrosa consist of (nonfenestrated/fenestrated) sheets of connective tissue and occacional elastic fibers
A
fenestrated
23
Q
_____ is found in surrounding the myelin sheaths in the lamina cribrosa
A
hyaluronate
24
Q
Hyaluronate (increase/decreases) with age and further (increase/decreases) with increase IOP
A
decreases
decreases
25
T/F in glaucoma the pores of the lamina cribrosa is round in eyes with physiologic cupping.
F. In glaucoma the pores of the lamina cribrosa are compressed . Healthy eye they are round in eyes with physiologic cupping
26
Lamina cribrosa pores are (smaller/larger) superiorly and inferiorly when compared to nasal and temporal
larger
27
Arcuate fibers occupy (inferior/lateral/medial/superior) ---pick two----(lateral/temporal) regions
superior and inferior
temporal
28
Axons from periopheral retinal take more (superior/inferior/peripheral) position
peripheral
29
(Acurate/papillomacular) fibers spread approx 1/3rd of the distal optic nerve primarily inferior temporal.
papillomacular
30
T/F retinal nerve fiber layer also intermingles iwth extramauclar fibers (may explain retention of central vision)
T
31
There are about ____ axons in the optic nerve
a) 1 trillion
b) 1 billion
c) 1 million
1 million
32
There are a (large/small) variation of axons in the optic nerve
large
33
Count of axons in the optic nerve (decrease/increase) with (increase/decrease) in area.
increase
| increase
34
Axon fiber diameter __to __ µm
a) 0.85-2.10
b) 0.65-2.10
c) 0.85-1.10
d) 0.65 - 1.10
0.65 to 1.10
35
T/F Axons in the optic nerve, of all sizes are mixed throughout although mean diameter appear to be more common nasal segment.
T
36
The size of the optic nerve reaches ___% before age 1
a) 90
b) 85
c) 95
d) 100
95
37
There is a greater susceptibility of damage , and potential for reversible cupping if a child doesn't develop the connective tissue of the __ __ completely
lamina cribrosa
38
There is a progressive loss of axons in the optic nerve of ___ to ___ a year
a)5500-12000
b4000-10000
c)5000-10000
d)4000 to 12000
4000 to 12000
39
T/F It has been proven that there is a selective loss of fibers with age
F. It has not been proven but is is a theory of Quigley and group
40
T/F because they eye is not fully developed at birth it can take damage and still "bounce back" and recover depending on the type of damage
T
41
If there is a accelerated loss of axons in the optic nerve this is from a disease called ___
glaucoma
42
T/F all cells die at an equal rate in the optic nerve
T
43
Retinal ganglion cells depend upon certain neuronal growth factors called ________
neurotrophins
44
T/F Axonal compression at lamina cribrosa block retrograde axoplasmic flow
T
45
T/F Nitric oxide is beneficial at certain concentration as a vasodilator
T
46
Nitric oxide at a (higher/lower) concentration can cause neurotoxicity
higher
47
Nitric oxide (activates/inhibits) mitochondrial function and (does nothing to/disrupts) DNA
inhibits, disrupts
48
T/F axoplasmic flow is a continuous pulsing , undulating movement of the cytoplsm between the cell body of a neuron , where protein synthesis occurs
T
49
Physical alterations, misalignment of fenestrae, backbowing of lamina cribrosa may lead to obstruction.
Support to this theory damage with elevated IOP occurs despite intact blood vessels.
- - this describes which theory --
1. mechanical theory
2. vascular theory
mechanical theory
50
Ischemia at least plays a role in the obstruction of axoplasmic flow in response to elevated IOP.
- - this describes which theory --
1. mechanical theory
2. vascular theory
vascular theory
51
Perfusion pressure is the difference between ___ and ___ pressure
arterial , venous
52
Mean ocular perfusion pressure = mean __-___
BP-IOP
53
T/F perfusion pressure states that blood vessel resistance also determines blood flow
T
54
______ mechanism is present in retinal vessels to maintain blood flow regardless of perfusion pressure
autoregulatory
55
The autoregulatory mechanism fails in what type of disease?
glaucoma
56
What are the two types of autoregulator mechanisms?
metabolic and myogeneic
57
(metabolic/myogenic) has a unclear mechanism
myogenic
58
(metabolic/myogenic) endothelial cells secrete vasodilators and vasoconstrictors
metabolic
59
Nitric oxide is a (vasolidator/vasoconstrictor)
vasodilator
60
Endothelin 1 is a (vasodilator/vasoconstrictor)
vasocontrictor
61
Raynaud's phenonmenon has a excessive (constriction/dilation) of vessels to cold
constriction
62
Delayed filling of superficial vessels of optic nerve in glaucoma shows that there is a favor to the (mechanical/vascular) theory
vascular
63
T/F pt with migraines have a higher association with glaucoma
T
64
Delayed filling of superficial vessels of optic nerve in glaucoma
Association of NTG with migraines
Excessive peripheral constriction of vessels to cold- Raynaud's phenomenon
Nocturnal blood flow different in glaucoma patients
Greater plasma concentration of endothelin-1
-- all of these show a favor for (mechanical/vascular) theory
vascular theory
65
T/F it is not clear whether mechanical or vascular factors are primary
T
66
Obstruction of the axoplasmic flow may be involved in pathogensis of (diabetes/glaucoma)
glaucoma
67
in a healthy optic disc the nuerual rim is broadest in which area? (inferiorly/superiorly/nasal/temporally)
all four
68
T/F in a healthy optic disc the disc is (smaller/larger) in area then teh neural rim
larger
69
Tilted disc syndrome has a (vertically/horizontally) oval disc
horizontally
70
T/F The myopic optic dissc has a sloped and tilted contour, and difficult to accuratly assess the extent of the disc rim thinning --(making it harder to diagnose glaucoma)
T
