Lecture 8 Flashcards
(118 cards)
1
Q
what % of out brain processes visual information
A
50%
2
Q
is the retina part of the cns or pns
A
cns
3
Q
what is called when the lens becomes opaque
A
cateracts
4
Q
this part of the eye regulate pupil size and is the color of the eye
A
the iris
5
Q
this part of the eye is the most sensitive part of the body
A
the cornea
6
Q
this part of the eye is the white part
A
the sclera
7
Q
this part of the eye is located inside the eyelid
A
conjuctiva
8
Q
what is the function of the extra ocular muscles
A
they help the eye move in different directions
9
Q
where does light enter the eye
A
through the lens
10
Q
after light hits the lens where does it go
A
to the retina
11
Q
T/F images are seen rightside up in the retina
A
false, they are seen upside down
12
Q
what will occur if the eyeball is either too long or too short
A
light rays will not focus properly
13
Q
where does light enter through the eye
A
the lens
14
Q
after light hits the lens where does it go
A
to the retina
15
Q
are images seen upside down or rightside up in the retina
A
upside down
16
Q
what will happen if the eye ball is either too long or too shote
A
light will not focus properly
17
Q
nearsightedness is also known as hyperopia t/f
A
false ,nearsightedness is also known as myopia
18
Q
t/f a short eyeball causes farsightedness
A
true
19
Q
another name for farsightedness is
A
hyperopia
20
Q
light rays from distant objects are …
A
parallel
21
Q
light rays form far away objects are
A
divergent
22
Q
are people with myopia able to see nearby or far away objects better
A
nearby
23
Q
does a lot of nearwork cause the eyeball to elongate or shrink
A
elongate
24
Q
what is a normal sized eyeball called
A
emmetropic
25
what muscles are responsible for controlling the lens curcature to properly focus the light on the retina
ciliary muscles
26
t/f the lens must change its shape in order focus light rays on distant objects
false
27
what is accommodation
the cilliary muscles contract to bulge the lens to refract the light properly
28
this part of the eye is where the blood vessels enter and exit the eye and where the retinal axons leave the eye
optic disk
29
name this part of the eye
a pit in the center of the eye
30
name this part of the eye : densest in photoreceptors and supports the highest acuity vision
fovea
31
t/f the optic disk lacks photoreceptors
true
32
what is the function of photoreceptors
they detect photons in their outer segments
33
which is more sensitive : rods or cones
rods
34
t/f rods can be responsive to one photon
true
35
which photoreceptors respond to waves of light
cones
36
what do the outer segments of rods and cones have
they have light absorbing chromophore retinal coupled to a protein called opsin
37
when retinal absorbs light what occurs
it chang es shapes
38
what does opsin activate
the g protein transducin
39
t/f photoreceptors have action potential s
false
40
what cause s changes in membrane potential in photoreceptors
light caused by graded potential
41
what does light activation cause in photoreceptors
hyperpolarization
42
photoreceptors are ______by light
hyperpolarized
43
when photoreceptors are depolarized what occurs
they release glutamate
44
is glutamate released in darkness or light
dark
45
what is released when photoreceptors are depolarized
glutamate
46
Are rods or Cones more sensitive to light at low levels
Rods
47
Do rods or cones saturate
Rods
48
Do rods or cones saturate
Rods
49
.?..... Are less sensitive to light but do not saturate
Cones
50
Are rods or cones associated with high acuity vision
Cones
51
What is high acuity vision
Vision with high detail
52
How many tyoes of Cones are there
3
53
Name the 3 types of cones
Short medium and long
54
The visual system determines color by comparing the........of different types of cones
Activity
55
Normals humans have 3 cones . These are called
Trichromatic
56
Color blind people are
Dichromatic
57
Where is the retinal pigment epithelium found
Extends around the tip of photoreceptors
58
What is the functional of retinal pigment epithelium
Recycles the outer tips of photoreceptors
59
When are the retinal pigment epithelium generated
After light exposure
60
Are photoreceptors far away or close to light
Faraway
61
Are horizontal cells inhibitory
Yeah.
62
Do horizontal cells hyperpolarize or depolarize
Hyperpolarize
63
Do horizontal cells receive input from a lot of cells or only a few
A lot
64
Do horizontal cells send output to a lot of a little photoreceptors
Only a few
65
How are horizontal cells connected
They are connected by gap junctions
66
When the center is hyperpolarized is more or less glutamate released
Less
67
When the center is light but the surrounding is dark do the depolarize or hyperpolarize
Hyperpolarize
68
When both the center and surround cells are lit does hypolorization occur
No
69
When do horizontal cells cause greater cone response
When there are small spots of light or dark not big fields
70
do visual systems respond better to contrast or absolute light
Contrast
71
Where do bipolar cells receive input from
Photoreceptors
72
Do bipolar cells have action potentials or graded potentials
Graded
73
What 2 receptors do off center bipolar cells express
AMpa and kainate
74
When glutamate comes in contact with Off center bipolar cells what occurs
They are depolarized
75
What do on center bipolar cells express
MGlur
76
When off center bipolar cells come in contact with glutamate what occurs
They are inhibited. ( hyperpolarized )
77
On center cells ..... To spots of .....
Depolarize light
78
Off center cells depolarize to ....
Dark spots
79
Are amacrine cells excitatory or inhibitory
Inhibitory
80
What is the purpose of amacrine cells
Serve to regulate the activity of bipolar cells
81
T/f. Amacrine cells regulate the activity of bipolar cells
True
82
Retinal ganglion cells receive input from what two cells
Bipolar and amacrine
83
Do retinal ganglion cells have graded potentials
No
84
Do retinal cells have action potentials
Yeah
85
Do retinal cells respond best to spots of light or big fields of light or dark
Spots of light
86
Do on center cells respond best to white spots surrounded by dark or dark spors surrounded by white
White spots surrounded by dark
87
Which ganglion cells respond best to the photopigment melanopsin
Iprgc
88
What does iprgc stand for.
Intrinsically photoreceptive retinal ganglion cells
89
What is the. Name of the photopigment that iprgcs respond to
Melanopsin
90
T/f iprgc can detect light independent of photoreceptors
True
91
Name the cell that contributes to detection of ambient light levels ,light driven reflexes like controlling pupil size and. Circadian rhythm .
Iprgcs
92
The rgc axons exit the eye and begin what
The optic nerve
93
Name the cell whose axons exit the eye and begin the optic nerve
Retinal ganglion cells
94
What is unique about the optic chiasm
Some of the axons cross to the other side
95
Another word for crossing of axons is
Decusasstion
96
After the optic chiasm what are the axons called
The optic tract
97
All of the information from the right visual field is directed to which side of the brain
The left hemisphere
98
Where does decussation occur
At the optic chiasm
99
What is the function of suprachasmatic nucleus
Circadian rhythm
100
What is the function of the protectum
Pupillary
101
What is the function of the superior colliculus
Orients movements of the head and eye
102
What is the function of the dorsal lateral geniculate nucleus of the thalamus
It is involved in processing
103
Which axons go to the primary visual cortex
Dorsal lateral geniculate nucleus
104
Connection from the dlgn to the cortex is called ...
Optic radiation
105
Do v1 neurons respond well to light
No
106
V1 neurons respond best to what
Moving oriented bars in a specific area of space
107
Why do v1 neurons respond best to bars
Because 2 or more inputs are summed together
108
T/f v1 neurons do not care about bar orientation
False, they care. Straight up and down is best
109
What is a tuning curve
Shows which stimulus an individual cell responds to best.
110
In humans neurons with similar orientations are clustered together in things called
Orientation columns
111
How is v1 organized
Retinotopically
112
Where is the first place in the visual system that has cells that receive information from both eyes
V1
113
Define ocular dominance
The degree to which a cell favors one eye over the other
114
T-/f cells with similar occular dominance do not cluster near each other
False
115
What is an ocular dominance column
Cells with similar occular dominance cluster together
116
T/f ocular dominance is plastic
True
117
Is ocular dominance always plastic
No only during the critical period
118
T/f every neuron in v1 has a set if characteristics that it responds to best
True
