1. Senses I: Light And Vision Flashcards

(47 cards)

1
Q

What is the tough outer coat that protects the entire eyeball

A

The sclera

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2
Q

What contains blood vessels that nourish the inner eye

A

The choroid

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3
Q

Light enters the eye through the

A

Cornea

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4
Q

What is the function of the iris

A

To adjust the size of the pupil in order to control the amount of light entering

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5
Q

The pupil decreases in size when exposed to

A

High intensity light

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6
Q

The pupil increases in size when exposed to

A

Low intensity light

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7
Q

The ability of the eye to focus on distant and nearby objects by changing the focal length is known as

A

Accommodation

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8
Q

What prevents the the eye from collapsing due to changes in atmospheric pressure

A

Aqueous humor

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9
Q

Retina contains what type of cells

A

Light sensitive cells

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10
Q

What are the two types of light sensitive cells

A

Rod and cone cells

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11
Q

Rod cells

A

Respond to light intensity

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12
Q

Cone cells

A

Respond to Color of objects

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13
Q

What is the location of most perception in the eye and is the area of sharpest vision

A

Fovea centralis (think central=focused)

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14
Q

Where are a maximum number of cones present

A

Fovea (most are of Color perception the more Color perception= more cones present)

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15
Q

When object is viewed it becomes ___ at the retina

A

Inverted

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16
Q

After objects are inverted at retina an electrical signal is formed and then sent to the brain via the

A

Optic nerve

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17
Q

The blind spot is known as the

A

Optic disk

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18
Q

There are no rods or cones on the

A

Optic disk (insensitive to light)

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19
Q

The optic nerve enters the eye at the

20
Q

When an individual is hit by a light beam the process goes

A

Posterior retina- photoreceptors- bipolar cells- innermost ganglion cells

21
Q

Those innermost ganglion cells generate

A

Action potentials

22
Q

The axons on those innermost ganglion cells weave together to form the

23
Q

The second cranial nerve is the

24
Q

The impulses from those action potentials generated by the ganglions are carried to the ___ via the optic nerve then into the ____ ___ ___

A

Thalamus, brain visual cortex

25
The thalamus (limbic system) is located in the? Forebrain Midbrain Hindbrain
Forebrain
26
Function of thalamus
Gathers/relaying sensory signals like visual and pain perception
27
The primary visual cortex of V1 is found in the
Occipital lobe (associated with visual processing and may receive these visual signals from the thalamus)
28
2 types of light sensitive cells or in other words PHOTORECEPTORS
RODS AND CONES
29
Peripheral vision is associated with the
Rods
30
__ only hit their activation thresholds in bright conditions
Cones (less sensitive to light- takes a bright light)
31
___ response time to stimuli is faster than __
Cones, rods
32
3 types of cones
S (blue) M (green) L (red) cones
33
S cones are sensitive to
Short-wavelength
34
M cones are sensitive to
Medium-wavelength
35
L cones are sensitive to
Long wavelength light.
36
Humans have ___ vision
Trichromatic (unmutated- normal red green blue cone shades)
37
The three cone pigments of blue green and red for detecting light have been shown to vary in their exact chemical composition due to a genetic mutation. This means
The shades may differ and those individuals will have cones with different Color sensitivity
38
Colour blindedness is
Mostly inherited and rarely acquired
39
Not being able to tell apart certain colours is
Colour blindness
40
The most common colours confused in colourblind people are
Red and green (daltonism)
41
The most usual form of colourblindness is known as
Daltonism
42
Seeing red as grey is
Daltonism
43
The most unusual form of colourblindness is known as
Monochromacy
44
Monochromacy is when
People see the world in black and white (rare)
45
Colourblindness is rarer in
Women - this is due to genetics because men have 1 X chromosome and women have 2 X chromosomes- in women they have shot at not having the gene since one X chromosomes may have it and the other wont; therefore, overriding the mutation. However in men they either have it or don’t in that X chromosome and can’t override it since they only have one X chromosome or they don’t have it at all
46
When 2 or more light sense cones don’t work this results in
Monochromacy (condition term: achromatopsia)
47
People with four or more types of cones are known to have (RARE: only some verified reports)
Tetrachromatic vision - almost always female - more intense colour vision