Module 4.2 - The Visual System Flashcards

1
Q

light travels in waves that vary in terms of 2 different properties. what are these 2 properties?

A

length and amplitude

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

true or false: different species see different wavelength

A

true

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

what are the 3 characteristics of light

A

wavelength, amplitude, purity

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

in what 3 ways are the characteristics of light experienced by us?

A

hue, intensity and saturation

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

hue

A

colour of the spectrum

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

intensity

A

brightness

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

saturation

A

colourfullness or density

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

sclera

A

the white, outer surface of the eye

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

cornea

A

the clear layer that covers the front portion of the eye and also contributes to the eyes ability to focus

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

pupil

A

regulates the amount of light that enters by changing its size; it dilates (expands) to allow more light to enter and constricts (shrinks) to allow less light into the eye

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

iris

A

a round muscle that adjusts the size of the pupil; it also gives the eyes their characteristic colour

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

lens

A

a clear structure that focuses light onto the back of the eye

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

how does the lens focus light onto the back of the eye?

A

through the process of accommodation

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

retina

A

lines the inner surface of the eye and consists of specialized receptors that absorb light and send signals related to the properties of light to the brain

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

true or false: the retina consists of a single layer

A

FALSE: the retina contains a number of different layers

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

photoreceptors

A

specialized receptors found at the back of the eye; they send information to biopolar and ganglion cells

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

optic nerve

A

a dense bundle of fibres that transmit activity from the ganglion cells to the brain

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

optic disc

A

an area on the retina with no photoreceptors

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

blind spot

A

area on the retina with no photoreceptors

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

why are we not aware of our blind spot?

A

because the mind “fills in” the blind spot

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

rods

A

photoreceptors that occupy peripheral regions of the retina; they are highly sensitive under low light levels

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

what colours are rods most responsive to?

A

black and grey

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

what is the ratio of rods to ganglion cells?

A

10:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

cones

A

photoreceptors that are sensitive to the different wavelengths of light that we perceive as colour

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

where are the cones clustered?

A

around the fovea

26
Q

fovea

A

the central region of the retina

27
Q

what is the ratio of cones to ganglion cells

A

1:1

28
Q

dark adaptation

A

the process by which the rods and cones become increasingly sensitive to light under low levels of illumination

29
Q

trichromatic theory/young Helmholtz theory

A

colour ion is determined by 3 cone types that are sensitive to short (blue), medium (green) and long (red) wavelengths of light

30
Q

what 3 colours are all other colours derived from?

A

red green and blue

31
Q

opponent-process theory

A

a competing theory of colour vision, which assume that the visual system treat pairs of colours as opposing or antagonistic

32
Q

opponent-process theory is consistent with _________

A

ganglion cells

33
Q

colour blindness

A

total inability to distinguish colours

34
Q

about ___% of all people are partly colour blind

A

4%

35
Q

colour blindness is often caused by what?

A

when one type of cones contains the wrong proteins (e.g., “red ones” incorrectly contain the protein found in “green ones”)

36
Q

near-sightedness/myopia

A

when the eyeball is slightly elongated, causing the image that the cornea and lens focus on to fall short of the retina

37
Q

farsightedness/hyperopia

A

when the length of the eye is shorter than normal, causing the image to be focused behind the retina

38
Q

feature detection cells

A

cells that selectively respond to simple and specific aspects of a stimulus, such as angles and edges

39
Q

what are the 2 streams of vision

A

dorsal stream and ventral stream

40
Q

dorsal stream

A

parietal lobe. visually guided movement. Patient DF

41
Q

ventral stream

A

temporal lobe. object recognition. involved with recognizing things

42
Q

prosopagnosia

A

face blindness

43
Q

where does someone with prospagnosia have damage?

A

have damage to the right fusiform gyrus

44
Q

perceptual constancy

A

the ability to perceive objects as having constant shape, size and colour despite changes in perspective

45
Q

shape constancy

A

we see objects as having a constant shape even though the shape of the retinal image produced by an object changes when our point of view changes

46
Q

location constancy

A

we perceive stationary objects as remaining in the same place even though the retinal image moves about as we move our eyes, heads, and bodies

47
Q

size constancy

A

we see an object as having constant size even when its retinal image becomes smaller or larger (e.g., an approaching car is not actually growing)

48
Q

brightness constancy

A

we see objects as having a relatively constant brightness even though the amount of light they reflect changes as the overall level of illumination changes

49
Q

colour constancy

A

we see an object as maintaining its hue despite the fact that the wavelength of light reaching our eyes from the object may change as the illumination changes

50
Q

binocular depth cues

A

distance cues that are based on the differing perspectives of both eyes

51
Q

convergence

A

when the eye muscles contract so that both eyes focus on a single object; it typically occurs for objects that are relatively close to you

52
Q

retinal disparity/binocular disparity

A

the difference in relative position of an object as seen by both eyes, which provides information to the brain about depth

53
Q

monocular depth cues

A

visual cues to depth or distance that can be used by one eye alone

54
Q

texture gradients

A

objects that are coarse and distinct at close range become fine and grainy at greater distances

55
Q

light and shadow

A

the shadow cast by an object allows us to detect both the size of the object and the relative locations of objects. in addition, closer objects reflect more light than far-away objects

56
Q

motion parallax

A

when an observer is moving, objects appear to move at different speed and in different directions

57
Q

relative size

A

if 2 objects in an image are known to be of the same actual size, the larger of the 2 must be closer

58
Q

heigh in plane

A

objects that are higher in our visual field are perceived as farther away than objects low in our visual field

59
Q

linear perspective

A

parallel lines stretching to the horizon appear to move closer together as they travel farther away

60
Q

interposition

A

nearby objects block our view of far-off objects, such as the umbrellas blocking the view of buildings behind them