Karius Special Senses: Vision Flashcards Preview

Neuro 2 exam > Karius Special Senses: Vision > Flashcards

Flashcards in Karius Special Senses: Vision Deck (76):
1

Direction of light rays for object that is far away

only parallel light rays enter the eye, little refraction to focus on retina

2

Direction of light rays for object that is nearby

the light rays are still diverging, need more refraction to focus on retina

3

Refraction

bending of light

4

Where is the first site that refraction occurs

cornea- bends light the most

5

Damage to cornea

very impactful on vision ex. astigmatism

6

2 parts of the eye that bend light?

cornea and lens

7

Why do we need the variable refraction provided by the lens?

to see things that are closer or far away

8

What does accommodation require

ciliary muscle, suspensory ligaments, lens itself

9

What happens to the lens during accommodation

make lens rounder

10

Function of ciliary muscle and suspensory ligaments during accommodation

control how thick the lens is

11

Ciliary muscle and suspensory lig during near vision

ciliary m contracts and tension on suspensory lig is released (becomes slack)

12

Shape of lens during near vision

becomes globular due to natural elasticity of lens

13

Increase curvature of the lens and refractive power

proportional - increased curvature increases refractive power

14

What does increased curvature of the lens do to light rays

allows nearby object to be bent sufficiently onto the retina

15

Ciliary muscle and suspensory lig during far vision

Ciliary muscle relaxes and tension of suspensory lig is increased

16

Lens shape during far vision

flattened

17

Decreased curvature of the lens and refractive power

proportional - decreased curvature decreases the refractive power

18

2 changes specific to near vision

convergence of eyes to point of focus and constriction of pupil

19

Pupil constriction for near vision

eliminates some of the diverging light rays
ex. squinting eyes when can't see- its reducing the opening of light and allowing us to focus better

20

Retina cell types

photoreceptors, bipolar, ganglion, horizontal, amacrine

21

What retina cell types make up direct pathway of light to optic nerve

photoreceptor, bipolar, ganglion cells

22

What retina cell types are part of processing in the retina

horizontal and amacrine

23

Cells of vertical pathway of retina

photoreceptor, bipolar, ganglion cells

24

Vertical pathway function

relaying visual information to the brain

25

Base for the vertical pathway

cones - color, high detail, require a lot of light

26

Amino acid released by photoreceptors

glutamate

27

Glutamate release when dark

high release, depolarization occurs

28

What happens when photon activates photoreceptor

decrease glutamate release, hyperpolarization occurs

29

Vertical pathway for cones

photoreceptor struck by photon of light --> hyperpolarization --> decrease glutamate release into BIPOLAR cell

30

2 kinds of bipolar cells

ON-center and OFF-center

31

ON-center bipolar cells

cause depolarization in center of cell and hyperpolarization surrounding the cell

32

OFF-center bipolar cells

cause hyperpolarization in the center of the cell and depolarization surrounding the cell

33

ON-center vertical pathway cones

metabotropic receptor is activated, decrease in cation influx

34

ON-center in the dark cones

ON-center is hyperpolarized, increase in glutamate

35

ON-center with light cones

ON-center is depolarized, decrease release of glutamate

36

OFF-center vertical pathway cones

AMPA receptor activated and increase in cation influx

37

OFF-center in the dark cones

OFF-center is depolarized due to less sodium release and lots of glutamate

38

OFF-center with light cones

OFF-center is hyperpolarized, glutamate is decreases, AMPA not activated

39

Components of Vertical pathway for Rods

rods, ON-center bipolar cells, A11 amacrine, cone ON-Center, ganglion cell

40

Process of vertical pathway for rods

Rods converge on ON-center bipolar cells --> synapse on A11 amacrine cell --> synapse on Cone ON-center bipolar cell --> activated ganglion cell

41

Rods

low light, not great on detail

42

What cell expresses metabotropic receptor because it's an "ON" cell

ON-center bipolar cell

43

A11 amacrine cell

tells you that you're in the rod pathway

44

What does the ON-cell center tell us

where something is

45

What does the OFF-center tell us

where it ends

46

Amacrine and horizontal cell function

provide inhibitory signals that modify the activity of neighboring photoreceptors, bipolar cells, or ganglion cells

47

Where do action potential occur

ganglion cells

48

What does each eye see?

sees two different visual fields to give depth perception

49

Left temporal retina

activated by light coming from right visual field

50

Right nasal retina

activated by light coming from right visual field

51

Right temporal retina

activated by light coming from the left visual field

52

Left nasal retina

activated by light coming from the left visual field

53

What occurs at optic chiasma

all information from right visual field is sent to same part of the brain (ex. right visual field sent o left side of the brain)

54

Visual field

what you see

55

Retinal field

light on retina

56

Lateral geniculate body

where axons travel and synapse

57

Function of LGN

control motions of eye, control focusing, identify major elements within our visual image, identify motion

58

Primary Visual Cortex (V1) neocortex

divided into 6 layers that each have different functions

59

Layer 1,2,3 of primary visual cortex

allow networking between V1 and other parts of cortex

60

Layer 4 of primary visual cortex

receives inputs form the LGN, where synapse occurs, tells us what to focus on

61

Layers 5 and 6 of primary visual cortex

send information BACK to the LGN

62

Columns of cortex of primary visual cortex

each column runs perpendicular to surface and has 6 layers. each column has different function

63

Neighboring columns

have related jobs

64

Macula of the retina

have lots of columns and receive info from macula

65

Peripheral regions of retina

less area in V1

66

Major job of V1

identify the edges/contours of the visual image

67

Major job of V2

Identify disparities in the visual images presented by the two eyes
Determines depth perception

68

Blobs

enable color detection, located in each colun

69

What does accurate color detection depend on

all 3 sets of cones

70

Major role of V4

complete processing of the color inputs

71

What can these layers NOT do

name the image, copy the image, aim at the image, recognize the image

72

Higher processing of visual inputs

dorsal and vental pathway

73

Dorsal pathway

relay info to motor cortices to act on visual input
ex. allows playing catch with friends

74

Ventral pathway

relay info to "processing of sensory input" area
ex. naming object and copying he object

75

Damage to temporal lobe

can impair either naming/recognizing of an object and not impair the other

76

Special function of temporal lobe

recognizing faces