Brainscape's Knowledge GenomeTM

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


See full index

perception midterm 1 > light and eyes > Flashcards

light and eyes Flashcards

1
Q

visible light spectrum

A

400-700 nanometer
blue to red

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

how light is seen

A
  • absorbed (not transmitted)
  • scattered
  • reflected
  • transmitted (passes through)
  • refracted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

field of view

A

the amount of world we are able to see with our eyes.
- we see most with both eyes
- we can control by moving them

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

Muscles around eye

A
  • medial and lateral rectus muscles: side
  • superior and inferior rectus
  • inferior and superior oblique
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

sclera

A

white of the eye which forms a tough protective coating

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

cornea

A

a transparent membrane at the front of the eye
- the first place light eneters

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

iris

A
  • colored part of the eye that controls how much light enters
  • a muscle
  • dilates in bright and contracts in dim
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

pupil

A

opening in the middle of the iris which control how much light comes in

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

lens

A

controls how much of the light is refracted onto retina
- 20% of refraction is done here

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

ciliary muscles

A
  • muscle that accomodate the lens to make it thicker for close objects and thinner for far away
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

retina

A

where the photoreceptors for transduction are
- made of 3 nucleus layers separated by 2 synaptic layers

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

aquous fluid + cornea

A

acount for 80% of the focusing of the eye

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

emmetropia

A

healthy 20/20 vision

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

myopia

A

near focus
- can see close but not far because of an elongation of the eyeball
- image forms in front of retina

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

Hyperopia

A
  • image forms behind
  • can see far but not close
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

astigmatism

A

blurred vision at any distance
- usually because of cornea

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

presbyopia

A

eyeball becomes less elastic with age and doesnt get as thick, so we can’t see close anymore

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

Ibn al Haytham

A
  • wrote the book of optics
  • thought that light rays come out of the eye
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

fundus

A
  • the back of the eye
  • can be seen with opthalmoscope
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

photoreceptor cells

A
  • in the outer layer of the retina
  • transduce sensory information
  • rods and cones
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

optic disk

A
  • a hole where blood vessels come from
  • because of this there are no receptors there so its a blind spot
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

rods

A

see dim light
- very sensitive
- 120 million
- more in the peripheral

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

cones

A
  • less sensitive
  • densely packed in fovea
  • color and detail
  • daylight conditions
  • 5 million
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

types of cones

A

S-cones: blue
M-cones: green
l-cones: red
- most L and least s

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

Transduction

A

photopigments in the rods and cones convert light into neural cones when a photon is absorbed and which cahnges membrane potential and starts an action potential

26
Q

visual pigment molecules

A

made up of opsin and retinal
- located inside rods and cones
- when retinal absorbs a photon it changes shape and sets on series of signals (isomeriztion)

27
Q

retinis pigmentosa

A

rods are affected which results in night blindness and if it affect cones it would ause full blindness

28
Q

molecular degeneration

A

destroys the macula (fovea) which creates a blind spot on the retina
- common with older people

29
Q

degrees of visual angle

A

the standard way to measure retinal size.
- function of both its actual size and distance from the observer

30
Q

dynamic range

A

our ability to see in bright and dark

31
Q

factors for dark/light adaptation

A

pupil dilation and photoreceptor replacement

32
Q

Photoreceptor replacement

A
  • in light photopigments are used up faster and fewer are there to process more light
  • so even though more photons are coming in, that light is thrown away because nothing is there to process it. and we are adapted to that luminance
33
Q

dark adaptation

A
  • takes longer for us to adapt to dark because rods takes 25 minutes to reach maximum sensitization
  • the first 8 minutes cones are mire sensitive and can see better but then they level off
34
Q

horizontal pathway

A

made up of horizontal and amacrine cells

35
Q

horizontal cells

A

connect perpendicularly to either rods or cones
- they make contact with photoreceptors and bipolar cells
- are responsible for lateral inhibition

36
Q

amacrine cells

A
  • lateral connection between bipolar and ganglion cells
  • help in contrast enhancement and temporal sensitivity
37
Q

vertical pathway

A

photoreceptors to bipolar to ganglion

38
Q

bipolar cells

A

retinal cells that synapse with on eor more rods or cones and with horizonatal cells and pass signals to ganglion cells

39
Q

types of bipolar cells

A

diffuse bipolar cells
midget bipolar cells

40
Q

diffuse bipolar

A

receives input from multiple photoreceptors

41
Q

midget bipolar cell

A

small cell that receives input from a single cone
- send input to p gnglion in parvocellular pathway

42
Q

ganglion cells

A

receive signals from bipolar and amacrine cells and connect into optic nerve
- p ganglion or M ganglion

43
Q

parvocellular pathway

A

-aka small cell pathway
midget bipolar to P ganglion to parvocellular
- acuity, color and shape
- good spatial, bad temporal

44
Q

P ganglion cells

A
  • aka midget ganglion cells
  • receive input from midget bipolar cells
45
Q

M ganglion

A

receive input from diffuse bipolar cells and connect to the magnocellular pathway
- aka parasol ganglion cells
- motion perception
- aka parasol

46
Q

magnocellular pathway

A

receive from diffuse bipolar and connect to magnocellular
- good temporal, bad spatial
- aka large cell pathway

47
Q

convergence

A

126 million photoreceptors converge into 1 millionbipolar cells

48
Q

rod convergence

A
  • about 50 rods to one bipolar cell
  • rods are more sensitive because of this convergence, since less light can activate bipolar cells because the input adds up
  • however, this makes them worse with detail and acuity
49
Q

cone convergence

A

6 cones to each bipolar cell
- in fovea its 1:1
- this ratio helps with acuity
- but less sensitive and needs more light to respond

50
Q

receptive field

A

the region on the retina in which stimuli influence a neuron’s firing rate
- each ganglion cell will respond to a specific location on the retina
-M ganglion have larger ones

51
Q

lateral inhibition

A
  • the horizontal pathway effect the recptive fields on ganglion cells
  • makes differences between light and dark even more noticeable (contrast/edges)
52
Q

on center

A

excited by light falling on center of ring and inhibited by light on surround

53
Q

off-center

A

inhibited by light falling in center of ring and excited by light on surround

54
Q

mach bands

A

because of lateral inhibition, the light edges get less inhibition from the dark edge making it look lighter and the dark line gets more inhibition from light edge making it look darker

55
Q

herman grid

A
  • ## seeing dots at the intersection can be explained by lateral inhibition
56
Q

visual acuity

A

smalles spatial detail that our visual system can resolve
- sharpness
- depends on optical factors and sensorineural factors

57
Q

visual angle

A

the angle that takes up space in our

58
Q

spatial frequency

A

how often a pattern, such as stripes or changes in brightness occur within a given area

59
Q

filtering out high frequency

A
  • makes image look blurrry
  • filtering out low would make us see the edges
60
Q

fourier analysis

A

mathematical procedure where signals are separate into components sine waves at different frequencies.
- the visual system breaks down images into a vast number of sine wave gratings with particular frequencies

61
Q

contrast sensitivity

A

shows how well we can detect different levels of contrast at different spatial frequencies
- higher contrast is easier to see

perception midterm 1 (3 decks)

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