Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

neuro lectures > the eye and visual system > Flashcards

the eye and visual system Flashcards

1
Q

how many layers does the eye have

A

3

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

why do we need 2 eyes (2)

A
  • to see in 3D (stereopsis)
  • widens our visual field
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

what are the 3 layers

A

outer
middle
inner

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

what is the outer layer made of

A

sclera and cornea

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

what is the middle layer made of

A

uvea/ choroid

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

what is the inner layer made of

A

retina

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

describe sclera structure

A

cross linked collagen fibres - makes it white
tough fibrous outer coat

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

describe cornea

A

transparent
also made of collagen but the fibres are laid out in parallel
must have a smooth spherical surface

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

what is the limbis

A

the area where sclera and cornea meet.
this is where most stem cells of the cornea are

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

functions of sclera

A
  • gives protection to eyeball since its made from a tough layer of collagen
  • maintains shape of eyeball
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what does the sclera serve as an insertion point for

A

the external muscles of the eye

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

what is the sclera a continuation of

A

dura mater and cornea

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

what does choroid do

A

blood supply and nutrition to retina

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

what is middle layer made of

A

iris
ciliary body
choroid

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

what is the iris

A

coloured part at front of the eye
contains dilator and sphincter pupillae muscles
pupillary reflexes

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

what is melanoma

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

what is retina

A

neurofibre layer of the eye specialised organ of phototransduction
has many layers

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

what does the retina produce

A

vitreous humour - acts as a collagen scaffold, helps maintain intraocular pressure and is important in the transmission of light

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

where does light pass through in order to project an image on the retina

A

light passes through the pupil from
the visual field to project an image
onto the retina.

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

what is the fovea centralis

A

An object that attention is focused on, projects an image that is centred near the posterior pole of the eye along the
visual axis, this point is known as
the FOVEA CENTRALIS

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

what is the macula latea

A

the surrounding 1cm to the fovea centralis

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

what is the retina specially modified for at the fovea centralis and macula latea

A

for maximal visual acuity (resolving power)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

what is the optic disk

A
  • a region medial to the macula
  • where retinal axons accumulate to
    leave the eye
  • optic nerve forms here
  • photoreceptors are absent in this region - so its called the blind spot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

how much of the cornea is responsible for retractive power

A

2/3
the other 1/3rd comes from the inter ocular lense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
unique feature of inter ocular lens
never stops growing throughout life keeps producing cells in ECM problem of this - develop cataracts
26
what happens to lens as it grows
becomes less pliable - less responsive
27
what is presmyopia
as people age they become more long sighted
28
how many layers in cornea
5
29
what are the 5 components of cornea (from outer to inner)
1. epithelium - can be regenerated 2. bowman’s layer 3. stroma 4. descemets layer 5. endothelium - cannot be regenerated
30
what does endothelium do
keeps cornea hydrated by actively pumping water out of stroma keeps cornea clear (since water molecules alter the regular spacing between collagen fibres & cause opacity)
31
what does ciliary body do
holds lens and suspensory ligaments in place as it contracts and expands made of smooth muscle, which controls accommodation; the adjustment of the lens in the eye so that clear images of objects at different distances are formed on the retina
32
where does ciliary body get innervation from
the parasympathetic system
33
most anterior aspect of choroid
iris
34
function of iris
Contains & controls the size of the pupil which lets light in - Sphincter muscles (circular fibres) make the pupil smaller [parasympathetic] - Dilator muscles (radial fibres) make the pupil larger [sympathetic] Gives eyes their colour
35
what does posterior segment refer to
anything from posterior segment of lens to back of eye
36
what does anterior segment refer to
divided into anterior and poster chambers
37
what does the lens divide
anterior and posterior segment
38
what do ciliary bodies produce
aqueous humour maintains pressure of eye bathes anterior chamber travels from ciliary body, through pupil , out to anterior chamber and then drains through anterior chamber at an angle between iris and cornea
39
what is glaucoma
increased pressure in eye damages nerves
40
what does outer retina contain and what does it do
photoreceptor cells send signals inwards to retina then chemical reactions happen synapses with other cells eventually send signal back
41
2 types of photoreceptor cells
rods and cones
42
what is retinal pigement epithelium (RPE)
Contains photoreceptors (rods & cones) so it is able to convert light into electric impulses (PHOTOELECTRIC TRANSDUCER) which are transmitted to ganglion cells which go on to make optic fibres and eventually the optic nerve
43
difference between rods and cones
cones give colour rods are black and white cones give high resolution rods give low resolution
44
when are rods more important
in dim lighting they are very sensitive to light also important for peripheral vision
45
location of rods and cones
the more central u get the more cones u get the more peripheral u get the more rods u get
46
what is the macula latea
central area of retina responsible for central vision and clarity and colour
47
does damage to peripheral affect vision
no you can still see but damage to any point or macula will affect vision
48
configuration of rods and cones
rods - many to one cones - one to one
49
what do rods and cones do
send signals to bipolar cells
50
photo transduction
light photons come in they cause a chemical change signal goes down changes conformation recycled back through and enzyme
51
what is emmetropia
6/6 vision
52
what is myopia
53
what is hypermetropia
refractive power is too low image forms on back of retina instead of in retina can see far but not close these people are given a plus lens
54
causes of hypermetropia
corneal curvature too shallow lens not flexible enough axial length of eyeball too short
55
causes of myopia
corneal curvature too steep axial length of eyeball too lomg
56
what is adnexae
term used for near by objects
57
function of lids
protects eye tear fill distribution blocks light
58
what does tarsal plate do
separate eyes into 2 layers
59
3 components to tear film
anterior lipid - prevents evaporation middle aqueous - gives fluidity and nutrition posterior mucus - maintains rest of tear film
60
describe anterior lipid layer of tear film
secreted by meibomium glands, provides a hydrophobic barrier to prevent the aqueous layer evaporating
61
describe middle aqueous layer of tear film
secreted by lacrimal glands, regulates transport through the cornea and prevent infection
62
describe posterior mucus layer of tear film
secreted by goblet cells, provides a hydrophilic layer that allows for the even distribution of the tear film
63
eyes blood supply
via the ophthalmic artery - is a branch of the internal carotid artery, arising immediately distal to the cavernous sinus. - ophthalmic artery gives rise to many branches, which supply different components of the eye.
64
what supplies the inner surface of the retina
The central artery of the retina Occlusion of this artery will quickly result in blindness.
65
venous drainage
superior and inferior ophthalmic veins. These drain into the cavernous sinus, a dural venous sinus in close proximity to the eye.
66
where is lymphatic drainage from
the conjuctiva not from eye drainage to submandibular and pre auricular nodes
67
what does the glandular epithelium do
produces; aqueous humour & nutrients for cornea & lens
68
what is aqueous humour made of
mainly water and electrolytes
69
what does aqueous humour do
maintains intraocular pressure (15mmHg)
70
why is choroid darkly pigmented
so it can absorb stray photons
71
what are the layers that which a photon must travel through the eye (12)
1. Tear film (transmission) 2. Cornea (transmission & refraction (contributes to 2/3rds of refraction) 3. Aqueous humour (transmission) 4. Lens (transmission & refraction) 5. Vitreous humour (transmission) 6. Ganglion cell (transmission) 7. Amacrine cell (transmission) 8. Bipolar cell (transmission) 9. Horizontal cell (transmission) 10. Cone (transduction) 11. Rods (transduction) 12. Pigmented epithelium (absorption of excess photons)

neuro lectures (15 decks)

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