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TCU A+P > Chapter 16A (eye) > Flashcards

Chapter 16A (eye) Flashcards

1
Q

what is refraction

A

the light waves being bent

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2
Q

what are the three places that refraction occurs in the eye

A

going into the cornea, as they enter the lens, and as they exit the lens.

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3
Q

what is the goal of refraction

A

to allow the the light waves to converge on the retina.

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4
Q

what are cataracts

A

clouding of the crystallins

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5
Q

what is accommodation

A

when the lens fattens up as a result of ciliary zonules becoming slack.

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6
Q

During accommodation the zonules will __ and the ciliary muscle __.

A

slack, contracts

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7
Q

As the ciliary muscle contracts it __ the lens.

A

reaches closer to

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8
Q

__ is used when looking at something 20 feet or more away.

A

Emmetropia

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9
Q

The light rays coming towards your cornea are ___coming to the cornea in emmetropia

A

running parallel

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10
Q

With accommodation closer than 20 ft away are the light rays parallel or converging?

A

converging

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11
Q

is the lens flat or bulging during accommodation closer than 20 feet

A

bulging

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12
Q

The __ is taking the light waves in then refracting them and converge them at the__

A

cornea, retina.

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13
Q

When looking at something from far away the __ system is engaged.

A

sympathetic

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14
Q

__ is when the eyes medially rotate.

A

`Convergence

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15
Q

The retina is called the ___because that’s where it has all of the __

A

neural layer, photoreceptors.

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16
Q

why is the optic disc called the blind spot

A

because there are no photoreceptors

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17
Q

The photoreceptors are farthest back in the retina in the__

A

pigmented layer.

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18
Q

Rods __ in the dark and when this happens you cannot see.

A

depolarize

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19
Q

As rods are depolarizing they are inhibiting the __. In order for ___ to depolarize the photoreceptors need to __.

A

bipolar cells, bipolar cells, hyperpolarize

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20
Q

__ cells are the second order neurons in a visual pathway the __ cells are the first order.

A

Ganglion, bipolar

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21
Q

The optic nerve is formed by __ cells.

A

ganglion

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22
Q

If you want to see something you want your rods to __so the bipolar cells can ___where they will release excitatory neurotransmitters.

A

hyperpolarize, depolarize

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23
Q

The outer segment of rods and cones are where you find __

A

photopigments.

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24
Q

__is found in rods and is a combination of opsin and retinol.

A

Rhodopsin

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25
Q

The photopigment in a cone is called __

A

photopsin.

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26
Q

Different __of light is what translates color.

A

wavelengths

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27
Q

__ give you color vision because they respond to different wavelengths of light.

A

Cones

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28
Q

__are the only ones that can function in a low light situation.

A

Rods

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29
Q

Rods are mostly found in the ___ while the cones are clustered around the ___

A

periphery of the retina, macula lutea and fovea centralis.

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30
Q

Phototransduction means __

A

changing light energy or changing light to vision

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31
Q

In the dark the rods are __which gives poor vision

A

depolarizing

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32
Q

In the dark rhodopsin is __

A

not absorbing light

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33
Q

___ is what’s responsible for the hyperpolarization of the rods.

A

The breakdown of rhodopsin

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34
Q

In the dark the rods are __ and the bipolar cells are __

A

depolarizing, hyperpolarizing

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35
Q

can you see while the rods are depolarizing and bipolar cells are hyper polarizing?

A

no

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36
Q

In the light cis-retinol straightens out to__. Then ___and ___ split.

A

trans-retinol, trans-retinol, opsin

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37
Q

what causes rods to hyper polarize in the light

A

the split of trans-retinol and opsin.

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38
Q

what happens after the hyper polarization of the rod in the light?

A

glutamate which is inhibitory in the eyes is released

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39
Q

glutamate is __ in the eyes but usually __ everywhere else.

A

inhibitory, excitatory

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40
Q

Optic tracts send fibers to the__

A

corpora quadrigemina.

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41
Q

The __ run along the margin of the eyelid and anchor the levator palpebrae superioris muscle.

A

tarsal plates

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42
Q

The__ secrete oil to prevent dry eye and keep the eyelashes from sticking together.

A

tarsal glands

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43
Q

The lacrimal caruncle contains __ glands in the medial commissure.

A

sebaceous and sweat

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44
Q

__ is a transparent mucous membrane that covers the anterior sclera and produces lubricating mucous.

A

Conjunctiva

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45
Q

is the Conjunctiva present in the region of the cornea?

A

no

46
Q

what is conjunctivitis

A

pink eye

47
Q

The __produces tears containing mucus, antibodies, and lysozyme to cleanse and moisten the eye.

A

lacrimal apparatus

48
Q

where do the tears drain into?

A

the lacrimal puncta→ lacrimal canals→ nasolacrimal duct→ nasal cavity.

49
Q

The __ is filled with aqueous humor that forms and drains continuously, supplying nutrients and oxygen to the__

A

anterior segment, lens and cornea.

50
Q

__ is when the aqueous humor does not drain and rising pressure can damage the retina and optic nerve.

A

Glaucoma

51
Q

what separates the anterior and posterior chamber?

A

the iris

52
Q

In the posterior segment the vitreous humor does what?

A

transmits light, supports the lens and retina, and helps maintain the shape of the eyeball.

53
Q

The__of the eyeball is the outer most layer composed of __

A

fibrous tunic, dense collagenous connective tissue.

54
Q

The ___ protects the shape of the eyeball and anchors the muscles.

A

sclera

55
Q

The __is the transparent layers of stratified squamous epithelium and contains pain receptors.

A

cornea

56
Q

The __ is the only tissue in the body that can be transplanted from one person to another with little or no possibility of rejection.

A

cornea

57
Q

The __ contains the iris which is a dual layer smooth muscle organ that regulates light entry

A

vascular tunic

58
Q

The__ is a vascular pigmented layer at the back of the eyeball that prevents the scattering of light within the eye.

A

choroid

59
Q

The __ is the ring of smooth muscles which attach to the lens by suspensory ligaments (ciliary zonules)

A

ciliary body

60
Q

The nervous tunic is comprised of the __

A

retina.

61
Q

As light is reflected off of objects it travels to our eyes and is refracted by what three structures

A

entering the cornea, entering the lens, exiting the lens.

62
Q

__ allows the lightwaves to converge at a focal point.

A

refraction

63
Q

The __ is a transparent, flexible structure which can change shape in order to focus light on the retina.

A

lens

64
Q

the lens is composed of layers of lens epithelium which contain __

A

protein crystallins.

65
Q

what are cataracts

A

clouding of the lens

66
Q

what is presbyopia

A

the decreased elasticity of the lens.

67
Q

When the ciliary body __the ciliary zonules become slack.

A

contracts

68
Q

if the lens fattens, will that help you focus on images that are far away or close up?

A

close up

69
Q

are light rays parallel or diverging in emmetropia

A

parallel

70
Q

are light rays parallel or diverging in accommodation

A

diverging

71
Q

is the lens fat or flat during emmetropia

A

flat

72
Q

is the lens fat or flat during accommodation

A

fat

73
Q

is the sympathetic or parasympathetic system used during emmetropia?

A

sympathetic

74
Q

is the sympathetic or parasympathetic system used during accommodation

A

parasympathetic

75
Q

what is accommodative pupillary reflex

A

the constriction of both pupils used during accommodation

76
Q

what is convergence

A

the medial rotation of both eyeballs during accommodation

77
Q

is emmetropia used for closer or farther than 20 feet vision

A

farther

78
Q

is accommodation used for closer or farther than 20 feet vision

A

closer

79
Q

what is astigmatism

A

the inability to simultaneously focus light rays that enter the eye on different planes. focusing on vertical lines may cause horizontal lines to go out of focus. caused by a deviation in the shape of the cornea so that it is shaped like the back of a spoon

80
Q

what is hyperopia

A

farsightedness- a condition in which the eyeball is too short. the retina lies in front of the focal point of the lens

81
Q

how can hyperopia be fixed

A

with convex lenses

82
Q

what is myopia

A

nearsightedness- a condition in which the eyeball is too long

83
Q

how can myopia be fixed

A

with concave lenses

84
Q

what is presbyopia

A

the reduced ability to accommodate for near vision with age. it is caused by declining flexibility of the lens

85
Q

how is presbyopia corrected

A

with bifocal lenses or reading glasses

86
Q

The retina is the layer which contains photoreceptors specialized for __

A

converting light energy into nerve impulses

87
Q

The optic nerve carries impulses from the __ to __

A

retina, the brain

88
Q

The optic disc is the site of the optic nerve attachment but lacks __ and __

A

rods and cones.

89
Q

__ is the neural layer that separates from the pigmented layer.

A

Retinal detachment

90
Q

the __ blocks photoreceptors from nutrients

A

vitreous humor

91
Q

what cell type contains photoreceptors responsible for low-light vision and non-color vision

A

rods,

92
Q

what cell type contains photoreceptors responsible for bright-light vision and color vision

A

cones

93
Q

what is the function of bipolar cells

A

they are first order neurons of the vision pathway

94
Q

what is the function of ganglion cells

A

second-order neurons of the visual pathway and the axons form the optic nerve

95
Q

what are the functions of horizontal cells and amacrine cells

A

they regulate connections between other cells of the retina and enhance and contrast and perception of vision

96
Q

what do rods regulate

A

they depolarize in the dark and hyper polarize in the light

97
Q

what do bipolar cells regulate

A

they depolarize when photoreceptors are hyperpolarized

98
Q

what do ganglion cells regulate

A

they depolarize due to excitatory neurotransmitters from bipolar cells

99
Q

the inner segment of rods and cones___

A

joins the cell body and contain mitochondria and other organelles

100
Q

the outer segment of rods and cones__

A

contains photopigments which change shape as they absorb light.

101
Q

Cones have photopsin which is able to respond to _ different light wavelengths.

A

3

102
Q

Rods and cones are distributed throughout the __

A

retina.

103
Q

In the dark the rods undergo an automatic __

A

depolarization.

104
Q

Axons of retinal ganglion cells form the __

A

optic nerve.

105
Q

Fibers of the optic nerves split at the __

A

optic chiasma.

106
Q

Medial fibers of the optic nerve decussate at the __and the lateral fibers remain __

A

optic chiasma, ipsilateral

107
Q

After the optic chiasma, most fibers of the optic tracts continue to the __. Other optic tract fibers send branches to the __ ending in the superior colliculi.

A

thalamus, midbrain

108
Q

__ connect fibers from the thalamus to the primary visual cortex in the occipital lobes.

A

Optic radiation

109
Q

Both eyes view the same images from slightly different angles. Vision is__, the left view is transmitted to the right occipital lobe.

A

contralateral

110
Q

Depth perception results from __ of the slightly different images. Loss of an eye results in loss of depth perception.

A

cortical fusion

111
Q

Damage to the optic chiasma, the optic tract, optic radiation or primary visual cortex can result in__

A

the loss of the entire contralateral visual field.

TCU A+P (12 decks)

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