Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

MED 310 > vision A > Flashcards

vision A Flashcards

1
Q

how is vision on the back of the eye (retina)

A

reduced, upside down

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

where is visual information transmitted to

A

the visual cortex

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

what does the vestibular apparatus cotnrol

A

balance

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

VOR purpose

A

keeps vision steady as head moves

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

orbit

A

bony cavity protecting the eye

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

nasolacrimal duct

A

drains tears into nasal cavity

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

lacrimal gland

A

secretes tears

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

retinal photoreceptor layers

A

ganglion cells
amacrine cells
bipolar cells
horizontal cells
cones and rods

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

rays must pass through

A

cornea
anterior chamber
pupil
lens
vitreous
inner retinal layers (ganglion, amacrine, bipolar, horizontal) to reach photocereptors

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

rays do not have to pass through

A

iris, retinal pigment epithelium, choriocapillaris, sclera

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

visual based neural signals pass thorugh

A

photoreceptors, intermediate retinal neurons, retinal ganglion cells (optic nerve) to LGN to visual cortex

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

where are blood vessels located in the eye

A

choroid layer

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

what absorbs excess light in the retina

A

pigment epithelium

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

what cell axons become the optic nerve

A

retinal ganglion

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

where must light rays focus

A

fovea

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

what initiates resolution of the finest detail

A

on the fovea, maximally focused image. bc light strikes the photoreceptors directly in the fovea bc the overlying neurons are pushed aside. photoreceptors at the fovea are less obscured by inner retinal layers

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

is the lens convex or concave when it becomes more powerful

A

convex. converges divergent rays coming from close objects onto fovea

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

focal length

A

distance from the centre of the lens to the focal point

19
Q

what needs no lens accomidation

A

far objects farther than 20 ft lead to parallel rays

20
Q

what controls lens shape

A

muscles in ciliary body

21
Q

far focus

A

ciliary body muscles relax. zonule ligaments tighten, lens is stretched.
decrease power
rays focus on fovea

22
Q

far focus PANS OR SANS

A

sympathetically controlled

23
Q

near focus

A

ciliary body muscles contract moving it inwards. zonule ligaments loosen, lens is fatter and convex. converge rays from behind fovea
increase power

24
Q

near focus PANS OR SANS

A

Parasympathetically controlled

25
Q

ciliary body shape

A

donut of muscle around base of iris

26
Q

normal eye

A

emmetropic
far focused as default
near needs accomidation
lens gets fatter to converge and move light rays forward onto fovea as objects get closer

27
Q

neural pathways mediating accomodation

A

optic nerves to oculomotor nuclei to oculomotor nerves to ciliary body muscles

28
Q

oculomotor nuclei

A

edinger westphal nuclei

29
Q

optic nerve afferents

A

are driven from each eye and lead to binocular efferents controlling both eyes which leads to accomodation reflex

30
Q

low light conditions

A

iris dilator pupilae muscles contract
radial fibres shorten
pupil diameter increases

31
Q

high light conditions

A

iris constrictor pupilae muscles contract
concentric fibres shorten
pupil diameter decreases

32
Q

neural pathways mediating pupillary reflex

A

optic nerve to oculomotor nuclei to oculomotor nerves to iris muscles contrictor pupilae and dialator pupilae

binocular efferents from optic nerve afferents

33
Q

visual acuity

A

spatial resolving capacity of visual system ability to see fine detail

34
Q

what is visual acuity limited by

A

diffraction, abherrations and photoreceptor density in the eye

35
Q

what does visual acuity target

A

recognition tasks, used in clinical visual acuity measurements that require the recognition or naming of a target such as snellen letters

36
Q

factors affecting visual acuity

A

refractive error
size of pupil
illumination
time of exposure of the target
area of the retina stimulated
state of adaptation of the eye
eye movement

37
Q

normal visual acuity

A

20/20 or 6/6 is the ability to resolve a spatial pattern separated by a visula angle of one minute of arc at 20 feet or 6 meters

38
Q

first number in snellen

A

test distance

39
Q

second number snellen

A

distance that the normal eye can see the same letters on the eye chart

40
Q

visual acuity

A

distance away from object that a normal subject can be to clearly see the detail

41
Q

how many min of arc are in the letter e

A

5 since there are 5 vertically contrasting parts to the e

42
Q

why are snellen letters sometimes sideways

A

to test ability to resolve a spatial pattern separted by a visual angle of one minute of arc

43
Q

legal blindness

A

20/200

44
Q

what does light not have to pass through that you keep forgetting

A

retinal pigment epitheliium and choriocapillaris

MED 310 (47 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions