Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

Ocular Anatomy > Lecture 11: Optic Nerve > Flashcards

Lecture 11: Optic Nerve Flashcards

1
Q

what cranial nerve is the optic nerve

A

CN II

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

CN II is axons of what?

A

retinal ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

is the optic nerve myelinated or unmyelinated?

A

myelinated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

how many myelinated axons make up the optic nerve

A

~1.2 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

what is the length of the optic nerve?

A

~ 4 cm in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

where does the optic nerve pass?

A

optic canal of the lesser wing of the sphenoid bone

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

CN II is the nerve fiber tract of what nervous system?

A

CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what are nerve fibers enveloped by?

A

myelin sheath derived from oligodendrocytes (CNS)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

T/F: the optic nerve is not prone to many diseases

A

F: the optic nerve is prone to many diseases of the CNS because it is a tract of the CNS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

how many regions can the optic nerve be divided into and what are they?

A
  1. Intraocular (prelaminar and laminar)
  2. Intraorbital
  3. intracanalicular
  4. intracranial
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what region is seen as the optic nerve head clinically?

A

the prelaminar portion of the intraocular region

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

the laminar portion of the intraocular region is the portion that passes where?

A

portion passes through the lamina cribrosa (LC)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

in the intraocular region of the optic nerve, are the fibers myelinated or unmyelinated?

A

unmyelinated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

if in the intraocular regions of the optic nerve, the fibers are myelinated what is the clinical relevance?

A

there is no visual consequence - it just makes it more difficult to evaluate the ONH.

also, a bigger blindspot will be present

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

in the intraocular region of the optic nerve, what is the height and width of the disc?

A

the disc is 1.9 mm in height, and 1.5 mm wide

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

in the intraocular region of the optic nerve, where is the cup slightly displaced?

A

temporally

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

in the intraocular region of the optic nerve, what color should the rim be and what does that mean?

A

pink - vascularized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

what is the C/D ratio?

A

between the cup and outermost edge of the optic disc

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

what 2 things determine the size of the cup?

A
  1. amount of regression of glial tissue surrounding hyaloid vasculature
  2. size od posterior scleral foramen
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Meniscus of Kuhnt

A

glial plaque - astrocytes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Inner Limiting Membrane of Elschig

A

astrocytes

22
Q

Inner Limiting Membrane of Retina

A

Müller cell fot plates

23
Q

where the ILM of the retina meets the ILM of Elschig is the site of what and outlines what?

A
  1. firm adhesion of the posterior vitreous

2. outlines the are of Martegiani

24
Q

where the ILM of the retina meets the ILM of Elschig is the site of what and outlines what?

A
  1. firm adhesion of the posterior vitreous

2. outlines the are of Martegiani

25
what gives rise to Bergmeister's Papilla?
excessive intermediary tissue of Kuhnt (glial plaque - astrocytes)
26
where do nerve fibers become myelinated?
posterior to the globe
27
what forms myelin sheaths?
oligodendrocytes
28
myelination, which is completed after birth, causes the optic nerve to what?
approximately triple in size
29
what do myelinated fibers allow for?
faster neuronal response
30
multiple sclerosis affects vision due to what?
demyelination of the optic nerve which slows visual transmission
31
the intraorbital post-laminar region is how long?
- 25 mm in length from posterior eye to optic canal | - 6 mm longer than the distance between the posterior surface of eye and optic canal (slack for movement)
32
what is enveloped by 3 meningeal sheaths?
intraorbital post-Laminar
33
what causes lamina cribrosa to bulge inward)
increased CSF pressure in the subarachnoid space (papilledema)
34
where do the CRV and CRA cross the SAS?
12 mm posterior to the eyeball
35
what happens if CSF is too high?
may compress central vein and appear as venous engorgement
36
pial sheath sends in septa to support what?
the nerve fascicles, CRV, and CRA
37
what part of the orbit does the optic nerve lie?
apex
38
where does the optic nerve lie within?
the muscle cone formed by the 4 recti muscles and their tendinous origins
39
how long is the intracanalicular portion of the optic nerve?
5 mm
40
where does the intracanalicular portion travel?
through the optic canal (optic foramen) formed by the optic struts of the lesser wing of the sphenoid bone with the ophthalmic artery
41
how long is the intracranial portion of the optic nerve?
10 mm
42
after leaving the optic canal, the optic nerve passes within what?
the SAS of the brain where it merges with optic chaism
43
the optic nerve is nourished by how many arterial systems? what are they?
1. pial 2. Central Retinal Artery (CRA - arteriole) 3. Short posterior ciliary arteries (arterioles)
44
the optic nerve is nourished by how many arterial systems? what are they?
1. pial 2. Central Retinal Artery (CRA - arteriole) 3. Short posterior ciliary arteries (arterioles)
45
blood supply to ON: pre-laminar region
both the central and peripheral portions are supplied by vessels from the surrounding choroid
46
blood supply to ON: laminar region
- centrally by branches from CRA | - peripherally by branches from the pial arterial network and circle of Zinn
47
blood supply to ON: retro-laminar region
- centrally by branches of CRA | - peripherally by branches from the pial arterial network
48
blood supply to ON: the four sources of vessels
1. branches from CRA or its branches 2. branches from the circle of Zinn (representing a system of anastomoses between branches from SPCA and pial arterial network 3. choroidal branches 4. pial branches
49
how does the optic nerve drain?
- primarily CRV | - some collateral flow through the vortex veins
50
Blind spot: No what on ON
No PR
51
what type of C/D ratio do glaucoma patients have?
high
52
ON Atrophy
- a tumor on the pituitary gland puts pressure on the nasal fibers crossing at chiasm - this will cause compression atrophy of the nerve fibers -- which will cause a whitening of the optic nerve in these areas

Ocular Anatomy (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions