10 - NS Eye & Vision Flashcards

(53 cards)

1
Q

What are the types of tunics of the eye

A
  1. fibrous tunic
  2. vascular tunic
  3. retina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

which are fibrous tunics

A

sclera and cornea

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

which are vascular tunics

A

choroid, ciliary body and iris

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

what type of layers is the retina

A

pigmented and nervous

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

how does the retina work

A
  1. incident light passes through the neural layers of the retina to reach the photoreceptors
  2. the pigmented retina absorbs excess light
  3. interneurons preprocess sensory info
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are retinal ganglion cells

A

they form CN II (optic nerve)

receive signals from photoreceptors and retinal interneurons

RGC projections transmit signals via the optic nerve to the areas in the brain used for visual processing

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

What are the interneurons

A

amacrine cells
bipolar cells
horizantal cells

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

parts of the retina

A

macula
fovea

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

Macula

A

3-5 mm oval region w/in the central region of the retina

surrounds the fovea

our central vision, most of our colour vision and the fine detail of what we see

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

Fovea

A

central fixation point for each eye
highest visual acuity (eye focusing)
- avascular (so u don’t see vessels)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the tool used to view the retina and how does it work

A

ophthalmoscope
dilates the pupil

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

What is the optic disc

A

beginning of the optic nerve and is the point where the axons of retinal ganglion cells come together.
blind spot

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

What happens aar of high CSF presure in the retina

A

buldge

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

what happens aar of loss of RGC axons

A

cupping

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

what is hyperopia + what lens is used

A

farsightedness - hard to read books(60% of population)
- eyeball is flattened
- focal point is behind the eye

positive diopter lense

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

What is presbyopia + what lens is used

A

can’t focus on objects that are near, far is fine
in old people

positive diopter lens

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

what is Myopia + what lens is used

A

nearsightedness - 20-30% of the population
eyeball is elongated
- focal point is before

negative diopter lens

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

what is lens cataracts

A

vision loss
begins at the age of 40
may also affect the cornea
can be corrected with surgery
- looks like many focal point

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

which SENSORY cranial nerves are involved in vision

A

CN II (optic): light detection
CN V (trigeminal): cornea sensation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Which MOTOR cranial nerves are involved in vision

A

CN III (oculomotor)
CN IV (trochlear)
CN VI (abducens)
CN VII (facial): lacrimal secretions

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

What are the structures of the primary visual pathway

A

optic nerve (CN II)
optic chiasm
optic tract
lateral geniculate nucleus (LGN)
optic radiations
primary visual cortex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What happens at the optic chiasm

A

optic nerves come together in order to allow for the crossing of fibers
enables vision from one side of both the eyes to be appreciated by the occipital cortex of the opposite side

23
Q

Lateral geniculate nucleus

A

passes through the thalamus

24
Q

What are the visual field defects

A
  1. monocular blindness (loss of vision in one eye)
  2. bitemporal hemianopia (temparol visual fields are gone - peripheral gone)
  3. homonymous hemianopia (half visual field gone - can’t see one side)
25
What causes glaucoma
increased intraocular pressure (excess production or insufficient drainage of aqueous humor)
26
How is vision affected by glaucoma
vision loss b/c damage to reinal ganglion cells -> cupping in optic disc progresses from the periphery to the center of the visual field
27
what is aqueous humor
produced by the ciliary body and drained by the trabecular meshwork
28
What are the motor nerves
3 -> occulomotor 4 -> trochlear 6 -> abducens 7 -> facial (lacrimal secretions)
29
what does CN III do
occulomotor levator palpebrae (opens eyelid)
30
what does CN VII do
facial orbicularis oculi (closing eyelid) innervates lacrimal glands which secrete tears
31
What is saccadic eye movements
expose the fovea of the retina to the entire visual scene - involves engaging the extraocular muscles of the eye
32
Where do extraocular eye muscles origniate
from the bones of the orbit and insert on the sclera of the eye - medial (nasal) aspect of the orbit
33
What are the rectus muscles
lateral, inferior, superior, medial straight pulls up and towards nose
34
What are the oblique muscles
superior, inferior angled pulls down and out
35
What nerve controls the lateral rectus
CN VI
36
What nerve controls the superior rectus
CN III
37
What nerve controls the medial rectus
CN III
38
What nerve controls the superior oblique
CN IV
39
Which muscles allow u to look up
CN III superior rectus and CN III inferior oblique
40
Which muscles allows you to look down
CN III inferior rectus and CN IV superior oblique
41
What is diplopia
double vision caused by problems with conjugate eye movements
42
What are the types of diplopia
occulomotor palsy/paralysis (CN III) - cant open eyelid trochelar palsy (CN IV) - can't rotate eyes within orbit Abducens palsy (CN VI) - cant not adbuct eye
43
What is ptosis
dropping of the eyelid - weakness of the levator palpebrae
44
What is exotropia
'down and out' deviation of the eye - decreased tone of all muscles except the lateral rectus ('out') and the superior oblique ('downward') lesion with CN III occulomotor nerve
45
What is esotropia
medial deviation of one or both eyes - lack of muscle tone of the lateral rectus muscle lesion with abducens (CN VI) nerve
46
How does lateral gaze work
brainstem circuits help - tying together r/l abducens nucleus with the opposite occulomotor nucleus to contract the l/f lateral rectus muscle and the l/r medial rectus muscle
47
What is convergence and accommodation
external eye muscles and pupils work together to position the eyes and the lens to focus
48
What happens when you change from far to near vision
1. contraction of both medial rectus m. (CN III) 2. contraction of ciliary body to focus lens 3. constriction of pupil to increase depth of field
49
what happens to the parts of the eyes when viewing a distant object
ciliary muscles relax, zonular fibers raunt and lens flattens = distant object nearly parallel light rays
50
What happens to parts of the eyes when viewing a close object
via accommodation ciliary muscles contract, zonular fibers lloose, lens becomes more spherical divergent light rays
51
how are pupillary constrictions accomplished What is it used for
through parasympathetic stimulation of the pupillary sphincter (limits light coming in) reduce light intensity and increase the depth of field for near vision
52
how are pupillary dilations accomplished What is it used for
through sympathetic stimulation of the radial muscles of the pupil increases light intensity and increases light exposure to the parafoveal regions of the retina useful to increase peripheral vision during a flight or fight response
53
What is ptosis which system causes this
dropping of eyelid sympathetic nerve