chapter 50-52 - exam 4 Flashcards
(101 cards)
1
Q
conjuctiva
A
connective tissue surrounding the eye
2
Q
sclera
A
extension of dura mater
3
Q
cornea
A
anterior surface of sclera, clear window
4
Q
choroid
A
vascular layer
5
Q
what does the choroid provide
A
nutrients to pigment layer + outer cones/rods
6
Q
iris
A
colored portion of eye
7
Q
circular fibers
A
decrease size of aperature + improve focus
8
Q
radial fibers
A
increase size of aperature + allow more light in
9
Q
pupil
A
hole in iris which light comes through
10
Q
lens
A
barrier between aqueous humor + vitreous humor
11
Q
retina
A
neural layer
12
Q
fovea centralis/macula
A
area of highest visual acuity. contains special cones
13
Q
optic disc
A
visual field blind spot, no photo receptors
14
Q
central artery of retina
A
branch of opthalmic a entering optic disc. supplies inner layers of retina
15
Q
anterior chamber
A
area containing aqueous humor from cornea to iris/pupil
16
Q
posterior chamber
A
area containing aqueous humor from iris/pupil back to lens
17
Q
vitreous chamber
A
area posterior to the lens contains semi-solid vitreous humor
18
Q
visible light electromagnetic waves
A
400-750nm
19
Q
ultraviolet electromagnetic waves
A
less than 400nm
20
Q
all cones together create what color
A
white light
21
Q
no cones/rods present create what color
A
black
22
Q
refraction
A
the bending of light at an angulated surface
23
Q
diopters
A
a measurement of the ability of a lens to bend light
24
Q
accommodation
A
the ability to increase or decrease refractive power
25
what provides the greatest amount of refraction for light entering the eye
the cornea
26
what provides variable refractive power to accommodate for near vision
the lens
27
convex sphere provides...
a focal point
28
convex cylinder give a...
focal line
29
convex lens _______ rays
converge
30
concave lens ______ rays
diverges
31
what will increase the focal distance
placing a convex lens in front of the eye, looking at object far away, increasing thickness or convexity of lens
32
hyperopia
far sighted
33
myopia
near sighted
34
hyperopia light source
parallel light rays from distant source
35
myopia light source
divergent light rays from near source
36
hyperopia _______ lens convexity
increases
37
myopia ______ lens convexity
decreases
38
what type of lens corrects hyperopia
convex
39
what type of lens corrects myopia
concave
40
presbyopia
loss of lens accommodation + near vision due to old age
41
emmetropia
normal physiological vision
42
hyperopia
focal point of parallel rays is beyond the retina
43
myopia
focal point of parallel rays is in front of retina
44
accommodation for near vision
increasing the refractive power of the lens to shorten the focal distance to adapt to divergent light rays for near vision
45
radial fibers role in accommodation for near vision
dilates pupil to let more light in for fight or flight response
46
circular fibers role in accommodation for near vision
constrict the pupil to increase visual acuity
47
lens role in accommodation for near vision
divergent rays entering retina trigger a reflex that causes ciliary muscles to disrupt suspensory ligaments
48
muscles role in accommodation for near vision
medial rectus m contract causing the eyes to maintain stereopsis
49
afferent limb accommodation reflex
light in retina to brainstem by CN II
50
efferent gse limb accommodation reflex
release ACH to motor endplate nicotinic receptors
51
efferent gve limb of accommodation reflex
preganglionic axon releases ACH, bind to nicotinic recceptors. causing an action potential to be fired
52
What helps adjust the depth of focus
Constriction
53
Size of known objects
Object that project a larger image on the retina are perceived to be closer
54
Stereopsis/binocular vision
Object far away focus at closer points on the right + left retina
55
Moving parallax
Objects that are closer move more quickly through the visual field than objects farther away
56
What produces aqueous humor
Ciliary processes on ciliary body
57
What drains aqueous humor
Canal of sclemm (iridocorneal angle)
58
Layers of the retina
Pigment cell layer, rods/cones layer, outer nuclear layer, outer plexiform, inner nuclear layer, inner plexiform, ganglion cell layer
59
Pigment cell layer function
Stores vitamin A + melanin
60
Layer of rods/cones
Photons of light bind + trigger a conduction of current
61
Outer nuclear layer
Contains nucleus/DNA
62
Outer plexiform layer
Synaptic body of rods/cones communicate w/dendrites of interneurons
63
Inner nuclear layer parts
Horizontal cells, bipolar cells, amacrine cells
64
Horizontal cells
Lateral inhibition to increase contrast for visual acuity
65
Bipolar cells
Carry info from rods/cones to ganglion cells
66
Amacrine cells
Help tract an image across the retina, analyze the visual signal, modify the signals + relay to neighboring ganglion cells
67
Inner plexiform layer
Synaptic ends of bipolar + amacrine cells synapse on dendrites of ganglion cells
68
Ganglion cell layer parts
Type M ganglion cells + type P ganglion cells
69
Type m ganglion cells pathways
Carry infor from rods to magnocellular layers of thalamus to layer 4 of primary visual cortex
70
What do type m ganglion cells help interpret
Position, form, + motion
71
Type p ganglion cells pathways
Carry info from cones to parvocellular layers of DLG nucleus to thalamus to peripheral areas of layer 4 of primary visual cortex
72
What do type p ganglion cells helpp interpret
Visual detail, color, texture, meaning
73
What do type m ganglion cells carry info from
Rods
74
What do type p ganglion cells carry info from
Cones
75
What does rhodopsin decompose into
Metarrhodopsin II
76
What does metarrhodopsin II breakdown into
Scotopsin + all trans retinal
77
What causes the closure of sodium channels and hyperpolarization
Metarrhodopsin breaking down into scotopsin + all trans retinal
78
What is all trans-retinal converted to
11-cis retinal or vitamin A
79
What has the fastest response to dark adaptation
Pupil dilation
80
What is the second fastest response to dark adaptation
Neuronal adaptation
81
What is the slowest + most effective response to dark adaptation
Rod photoreceptors
82
Old visual pathway function
Basic reflexive behavior, pupillary light reflex, accommodation reflex, eye movement/tracking reflex
83
Old visual pathway pit-stops
Hypothalamus + midbrain superior colliculus
84
New visual pathway function
85
New visual pathway pit-stops
86
New visual pathway lesions
Monocular vision loss, bitemporal hemianopia, homonymous hemianopia
87
Monocular vision loss
Problem with right/left retina or optic nerve. Specific to side
88
Bitemporal hemianopia
Loss of both right + left temporal visual fields. Optic chiasm lesion
89
Left homonymous hemianopia
Loss of both left visual fields. Lesion in right optic tract
90
Right homonymous hemianopia
Loss of both right visual fields. Lesion of left optic tract
91
Voluntary eye fixations
Choosing what to look at. Premotor cortex/frontal lobes
92
Involuntary fixation
Reflex that keeps your eyes centered on an object. Secondary visual areas of occipital lobe
93
Saccades
Eyes fix on 1 highlight at a time + quickly jump to next highlight
94
When does a person use saccades eye movement
When reading or riding in a car
95
Pursuit movement
Eyes track a moving object
96
Accommodation
A reflex to keep the image in focus on the fovea centralis as you look at a nearing object
97
Dilation of the pupil mechanism is used when
Sympathetic stimulation or when something is pretty
98
In pupil dilation in darkness, where does the hypothalamus send neurons
Lateral horn of T1-3
99
In pupil dilation in darkness, where does the lateral horn send neurons
Superior cervical ganglia
100
What causes the eyes to dilate
Preganglionic ACH binds to nicotinic postganglion receptors. Postganglionic norepinephrine binds to alpha-1 adrenergic receptors to dilate pupils
101
Pupil constriction in bright environment
STUDY SHEET
