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physiological Optics Mid > Pre Finals > Flashcards

Pre Finals Flashcards

imemorise

1
Q

the ability of the eye to adjust its focal length

A

Accommodation

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2
Q

a condition in which the lens of the eye becomes progressively unable to focus on objects close to the viewer

A

Presbyopia

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3
Q

This acts like a shutter of a camera.

A

Iris

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4
Q

In the middle of a normal iris is the

A

Pupil

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5
Q

It is an opening that, typically, is circular and is comparable to the aperture of a camera.

A

Pupil

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6
Q

It helps regulate the amount of light passing through to the retina

A

Pupil

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7
Q

As the amount of light entering the eye diminishes, the iris dilator muscle pulls away from the center, causing the pupil to ______

A

Dilate

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8
Q

When too much light is entering the eye, the _______ pulls toward the center, causing the pupil to “constrict” and allowing less light to reach the retina.

A

Iris sphincter muscle

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9
Q

encircles the pupil

A

Iris sphincter muscle

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10
Q

runs radially through the iris like spokes on a wheel

A

iris dilator muscle

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11
Q

When too much light is entering the eye, the iris sphincter muscle pulls toward the center, causing the pupil to _____ and allowing less light to reach the retina.

A

Constrict

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12
Q

When too much light is entering the eye, the iris sphincter muscle pulls toward the center, causing the pupil to constrict and allowing less light to reach the ____.

A

Retina

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13
Q

________ also occurs when the crystalline lens accommodates (changes focus) so that the eye can view something at a near distance. This reaction is known as the “near reflex.”

A

Constriction of the pupil

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14
Q

Also known as NEAR REFLEX

A

Constriction of the pupil

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15
Q

A representation of parasympathetic pathways in the pupillary light reflex can be seen here

A

parasympathetic response.

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16
Q

when the crystalline lens accommodates (changes focus)

A

Near reflex

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17
Q

is an aperture of the iris situated a little towards the nasal side of the iris center.

A

Pupil

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18
Q

Shapes of the pupil for humans

A

Circular

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19
Q

Shapes of the pupil for

Horses

A

Oval

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20
Q

Shapes of the pupil for cats

A

elliptical

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21
Q

This adjustment in the lens, known as _______, is necessary for bringing near and far objects into focus.

A

Accommodation

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22
Q

The process of bending light to produce a focused image on the retina is called _____.

A

Refraction

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23
Q

Ideally, the light is “refracted,” or redirected, in such a manner that the rays are _____ into a precise image on the retina.

A

Focused

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24
Q

Light entering the eye is first bent, or refracted, by the _______

A

Cornea

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25
Q

the clear window on the outer front surface of the eyeball.

A

Cornea

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26
Q

It provides most of the eye’s optical power or light-bending ability.

A

Cornea

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27
Q

After the light passes through the cornea, it is bent again — to a more finely adjusted focus — by the ______ inside the eye.

A

crystalline lens

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28
Q

The ____ focuses the light on the retina. This is achieved by the ciliary muscles in the eye changing the shape of the _____, bending or flattening it to focus the light rays on the retina.

A

Crystalline lens

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29
Q

Our ability to see starts when light reflects of an object at which we’re looking and enters the eye. As it enters the eye, the light is ______.

A

unfocused.

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30
Q

The first step in seeing is to focus the ______ onto the retina, which is a light-sensitive layer found inside the eye.
Once the light is focused, it stimulate cells to send millions of electrochemical impulses along the optic nerve of the brain. The portion of the brain at the back of the head interprets the impulses enabling us to see the object.

A

Light rays

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31
Q

The first step in seeing is to focus the light rays onto the ____

A

Retina

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32
Q

a light-sensitive layer found inside the eye.

.

A

Retina

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33
Q

Once the light is ______, it stimulate cells to send millions of electrochemical impulses along the optic nerve of the brain.

A

Focused.

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34
Q

True or false: The portion of the brain at the back of the head interprets the impulses enabling us to see the object.

A

True

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35
Q

T or F: Even with the light focused on the retina, the process of seeing is not complete.

A

True

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36
Q

Even with the light focused on the retina, the process of seeing is not complete. For one thing, the image is inverted, or upside down. Light from the various “pieces” of the object being observed stimulate nerve endings — photoreceptors or cells sensitive to light — in the retina.

A

Sensory interpretation

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37
Q

are mainly found in the peripheral retina and enable us to see in dim light and to detect peripheral motion.

A

Rods

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38
Q

They are primarily responsible for night vision and visual orientation.

A

Rods

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39
Q

Are principally found in the central retina

A

Cones

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40
Q

provide detailed vision for such tasks as reading or distinguishing distant objects.

A

Cones

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41
Q

They are necessary for color detection

A

Cones

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42
Q

These photoreceptors convert light to _____ that are transmitted via the nerves to the brain.

A

electrochemical impulses

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43
Q

Millions of _____ travel along the nerve fibers of the optic nerve at the back of the eye, eventually arriving at the visual cortex of the brain, located at the back of the head. Here, the electrochemical impulses are unscrambled and interpreted. The image is re-inverted so that we see the object the right way up.

A

impulses

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44
Q

T or F: The “sensory” part of seeing is much more complex than the refractive part — and therefore is much more difficult to influence accurately.

A

True

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45
Q

Is a complex peripheral nervous mechanism composed of many elements

A

Retina

46
Q

It is functional coat of the eye

A

Retina

47
Q

Retina came from the word “______” which means “network”

A

Rete

48
Q

a network of neurons-visual cells, bipolar cells and ganglionic cells

A

Rete/ retina

49
Q

An innermost layer which is a thin (0.1-0.5mm) transparent membrane

A

Retina

50
Q

It is attached to the underlying choroid only at the optic disc and ora serrata

A

Retina

51
Q

It is where the images are cast: acts as a screen of the eye.

A

Retina

52
Q

How thin is your retina

A

0.1-0.5mm

53
Q

Whats inside the retina

A

Rods and cones

54
Q

These two are light-sensitive cells which numbers up 120million or 6million, respectively.

A

Rods ans cones

55
Q

Pigments in the ____ can absorb a very small amount of light that reaches the retina.

A

Rods

56
Q

The pigment in the rod is called ____

A

rhodopsin

57
Q

or visual purple.

A

Rhodopsin

58
Q

It enables the eye to see shades of gray.

A

Rhodopsin

59
Q

There are three types of pigments found in the rods and cones.

A

Cyanolabe- absorbs blue light
Chlorolabe- absorbs green light
Eryhtrolabe- absorbs red lab

60
Q

The three pigments enables us to see more than how many colors?

A

200 colors

61
Q

responsible for the sharp images we see

A

Fovea

62
Q

located around the center of retina

A

Macula

63
Q

responsible for peripheral vision which allows us to see our side without turning our heads or eyes

A

Macula

64
Q

most rods are located in this area because of their higher ability to detect dark

A

Macula

65
Q

All cones and rods are connected to separate nerve ending which later meet in the ____

A

Optic nerve

66
Q

This nerve serves as a link between brain and eye. This makes it seem that the retina is an extension of the brain itself.

A

Optic nerve

67
Q

Sometimes when we look at things, our eyes fail to see a part of the object. We hit our _____

A

Blind spot

68
Q

the area where there are no rods and cones.

A

Blind spot

69
Q

Here, no image is formed

A

Blind spot

70
Q

T or F: we cannot see the blind spot because the image line of the blind spot of one eye deceive the other. Therefore, both blind spot are covered.

A

True

71
Q

A small depression in the center of the disc, where CRA enters and the CRV leaves in the eye

A

Physiological Cup

72
Q

Are found only nerve fibers

Absence of the retina renders this spot incapable of receiving impression of light known as blind spot (Mariotte’s spot)

A

Optic Disc

73
Q

Mariotte’s spot

A

Blind spot

74
Q

punctum caecum

A

Blind spot

75
Q

3 Nerve Sheaths

A

Dura
Arachnoid
PIA

76
Q

3.0-3.5mm, fibers from the ganglionic cells on reaching the surface of the rising bend at right angles & course over the retina to reach the optic disc

A

Optic Nerve

77
Q

Size of optic nerve

A

3.0- 3.5mm

78
Q

In small bundles they pass out of the eyeball through the lamina cribrosa in the scleral canal

A

Optic nerves

79
Q
  • from the ganglionic cell layer to their exit through the canal
A

Non-medullated fibers

80
Q
  • after passage through candles but they are devoid of neural
A

Medullated

81
Q

A dentate line about 8.5mm back of the sclera-corneal junction.

A

ORA SERRATA

82
Q

Ora means

A

Margin

83
Q

Serra means

A

A saw

84
Q

in the center of macula the retina is very much thinned down (0.1 mm) giving rise to a little pit or depression displacement by the bipolar cells and ganglionic neurons towards the periphery of the macula, drawing only the visual cells layer

A

FOVEA CENTRALIS

85
Q

Retinal area of greatest visual acuity (in daylight vision)

A

Fovea centralis

86
Q

the yellow spot- lying about 3.0 mm to the temporal side of the optic disc

A

MACULA LUTEA

87
Q

measures about 1-3.0 mm in diameter

A

Macula lutea

88
Q

yellowish due to the yellowish pigment (xanthophylls) in the bipolor cells & ganglionic layers

A

Macula lutea

89
Q

Special parts of the retina

A 
Macula lutea 
Fovea centralis 
Ora serrata 
Optic nerve 
Optic disc
Physiological cup
90
Q

the most interesting of all optical instruments.

A

Eye

91
Q

remarkable in how it forms images and in the richness of detail and color it can detect.

A

Eye

92
Q

However, our eyes commonly need some correction, to reach what is called “normal” vision, but should be called ______ rather than normal.

A

Ideal

93
Q

Image formation by our eyes and common vision correction are easy to analyze with the ______

A

Optics

94
Q

The ____ of the eye adjusts its power to produce an image on the retina for objects at different distances.

A

Lens

95
Q

has the greatest density of light receptors and the greatest acuity (sharpness) in the visual field.

A

Fovea

96
Q

The center of the image falls on the ____

A

Fovea

97
Q

variable opening of the eye

A

Pupil

98
Q

T or F: Our eyes perform a vast number of functions, such as sense direction, movement, sophisticated colors, and distance.

A

True

99
Q

Processing of visual nerve impulses begins with interconnections in the retina and continues in the _____

A

Brain

100
Q

The biggest change in the refractive index, and bending of rays, occurs at the _____ rather than the lens.

A

Cornea

101
Q

The process of adjusting the eye’s focal length is called .

A

Accommodation

102
Q

A person with normal (ideal) vision can see objects clearly at distances ranging from _____ to essentially infinity.

A

25 cm

103
Q

T or F: The eye is most relaxed when viewing distant objects, one reason that microscopes and telescopes are designed to produce distant images.

A

True

104
Q

Vision of very distant objects is called____, while close vision is termedaccommodated, with the closest vision being______.

A

Totally relaxed

Fully accommodated

105
Q

Yellowish pigment in the macula lutea

A

Xanthophylls

106
Q

Millions of impulses travel along the nerve fibers of the optic nerve eventually arriving at the ______

A

Visual cortex of the brain

107
Q

Here, the electrochemical impulses are unscrambled and interpreted. The image is re-inverted so that we see the object the right way up

A

Visual cortex of the brain

108
Q

How many rods are there

A

Upto 120million

109
Q

How many cones are there

A

Upto 6million

110
Q

Enables the eye to see shades of gray

A

Rhodopsin/ visual purple

physiological Optics Mid (2 decks)

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