Vision Flashcards

1
Q

Refractive eyes are good at

A

Resolution

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2
Q

Compound eyes are good at

A

Motion detection
Detecting multiple wavelengths
Detecting polarized light

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3
Q

Passage of light

A

Cornea → Anterior Chamber → Iris & pupil → lense → Posterior Chamber

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4
Q

Fovea

A

Greatest visual acuity

More cones than rods

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5
Q

Optic disc

A

Blind spot on retina, axons from receptors form the optic nerve

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6
Q

Tapetum

A

Reflective guanine crystals found in nocturnal animals

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7
Q

Name 5 cell types in the retina

A
Photoreceptors
Bipolar cells
Horizontal cells
Amacrine cells
Ganglion cells
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8
Q

Major refractive element

A

Cornea

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9
Q

Depth of field determined by

A

Iris & pupil

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10
Q

Accommodation

A

Lense

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11
Q

Rods are sensitive to

A

diffuse and scattered light

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12
Q

Rods are used in night\light vision

A

Night vision and Monochromatic vision

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13
Q

Cones are sensitive to

A

Color

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14
Q

Temporal and spatial resolution

Rods\cones

A

Cones

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15
Q

There are more rod\cones

A

Rods

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16
Q

Synaptic terminal of photoreceptors

A

Vesicles for neurotran

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17
Q

Inner segment of photoreceptors

A

Nucleus & organelles

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18
Q

Outer segment of photoreceptors

A

Membranous discs

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19
Q

What is the response to light depolarization or hyperpolarization?

A

HYPERPOLARIZATION

No action potential released in response to light

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20
Q

Sequence of hyperpolarization

A

Ca channels that are usually open in outer segment closes
Less Ca enters the cells
Less NT release

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21
Q

What happens to retinol when activated by light

A

Retinol gets converted from cis to trans

Opsin and retinal combine

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22
Q

What is responsible for the decrease in cGMP when activated by light

A

Phosphodiesterases

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23
Q

At rest levels of cGMP, Ca and Na are

A

High

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24
Q

When activated by light, levels of cGMP, Ca and Na are

A

Low

25
Q

Rhodopsin kinase is responsible for ___ by phosphorylating ______

A

Termination of a signal

Rhodopsin

26
Q

Rhodopsin Kinase is inhibited by high levels of ____ so is inhibited at rest

A

cGMP, Ca

27
Q

Phosphorylated rhodopsin binds to

A

Arrestin

28
Q

Arrestin bound to rhodopsin is responsible for

A

Retinol & opsin disassociation

29
Q

Myopia

A

Nearsightedness (concave)

30
Q

Hyperopia

A

Farsighted (convex)

31
Q

Loss of accomodation

A

Decrease in lens elasticity

32
Q

Cataracts

A

Opaque spots on the lens

33
Q

Retinal detattachment

A

Gap between pigmented epithelium and photoreceptor layers (embryologic defect in stalk formation)

34
Q

Macula degenration

A

Loss of pigment epithelium& evetually photoreceptors

35
Q

Vitamin A defiency

A

Vitamin A = trans-retinol

Used to make cis-retinol

36
Q

Blue color blind

A

Tritanopia

37
Q

Green color blind

A

Deuteranopia

38
Q

Red color blind

A

Protanopia

39
Q

Retinitis pigmmentosa

A

Photoreceptor degeneration

40
Q

M cells
Detect:
Size of receptive field:

A

Motion detectors

Large receptive field

41
Q

P cells
Detect:
Size of receptive field:

A

Color

Small receptive field

42
Q

M and P cells receive input from

M and P cells are ____ cells and are located in the ___

A

Receptor cells (rods and cones) and fire action potentials
Retinal ganglia cells
Lateral geniculate nucleus

43
Q

On Center Receptive Field

A

Increase in activity when CENTER is illuminated

Decrease activity when SURROUND is illuminated

44
Q

Off Center Receptive Field

A

Increase in activity when SURROUND is illuminated

Decrease activity when CENTER is illuminated

45
Q

On center receptors

A

Glutamate receptors

46
Q

Off center receptors

A

NMDA & AMPA

47
Q
W-type Ganglion Cells
Do they have center\surround organization?
Receptive to?
Function?
Found in the
A

No center surround organization
Blue light
Circadian rhythms & pupillary reflexes
Pretectal area & hypothalamus

48
Q

Visual neuronal pathway

A

Receptor cells
Retinal ganglia cells
Optic chiasm

49
Q

Where do nerves travel after reaching optic chiasm

A

Lateral geniculate Nucleus (80%)
Pretectal area
Superior colliculus
Hypothalamus

50
Q

Function of hypothalamus in response to light

A

Contains suprachiasmatic nucleus, involved with circadian rythems

51
Q

Function of superior colliculus

A

Integration of visual, somatic and auditory information

52
Q

Function or pretectal area

A

Contains W ganglia involved in pupillary light reflexes

53
Q

Lower visual field information projects

A

Above the calcarine sulcus in occipital lobe

54
Q

Upper visual field information projects

A

Below the calcarine sulcus in occipital lobe

55
Q

Meyers loop

A
Visual fibers (inferior retina) from lateral geniculate nucleus to the cortex
Some fibers pass through temporal lobe
56
Q

Damage to meyers loop

A

Fibers are from the inferior retina so loose SUPERIOR visual field (half) = Quadrantopia

57
Q

Axons originating from the temporal side of the retina express

A

Eph B1 so they do not decussate

58
Q

Axons from the nasal side of the retina express neither Eph B1 or B2 so they

A

decussate

59
Q

Optic chiasm expresses

A

Ephrin B2 so repels temporal axons that do not decussate