Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

PHYSIO II Exam #1 - Lo > Lec 05- Vision > Flashcards

Lec 05- Vision Flashcards

1
Q

What is refraction?

A

bending of light waves at an angulated surface of a transparent material

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens to light after striking a perpendicular surface?

A

continues on through WITHOUT bending

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What 2 things does the degree of refraction depend on?

A
  • Ratio of 2 refractive indices of the 2 transparent media

- Degree of angulation between the interface and the entering wave front of the light waves

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is refractive index?

A

ratio of the velocity of light in air/velocity of light in substance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the RI of air?

A

1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is refractive power?

A

how much a lens bends light waves

diopters

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How much is 1 diopter?

A

1 meter/focal length of lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the distance from the center of the lens to the focal point?

A

focal length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which lenses don’t have a focal point because they are diverging?

A

concave lenses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

The object as projected on the retina will be _________ and _________

A
  • reversed

- inverted

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What does the iris do?

A

controls the amount of light entering the eye from darkness to light conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What does depth of focus of the lens do as the pupillary diameter decreases?

A

increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is Emmetropia?

A
  • Normal eye (depth of focus)
  • All distant objects seen clearly
  • When ciliary muscle relaxed= parallel light rays from distant objects are in sharp focus on the retina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is Hyperopia?

A
  • Farsightedness
  • Eyeball = too short
  • Lens system = too weak (occasionally)
  • All distant object seen clearly
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is Myopia?

A
  • Nearsightedness
  • When ciliary muscle relaxed= light rays from distant objects are focused in front of the retina
  • Eyeball = too long
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

How is Myopia fixed?

A

Diverging lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

How is Hyperopia fixed?

A

Converging lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Light from a distant point source will normally create a spot with a diameter of _________ and a center that is brighter than the periphery.

A

11 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What is the average diameter of a cone in the retina?

A

1.5 um

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What is the max visual acuity for two-point sources of light?

A

1.5 - 2mm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Which humor is formed by the ciliary processes?

A

aqueous humor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the ciliary apparatus consist of?

A

2 opposing layers of epithelial cells with a space between them

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What ions are actively transported into the space of the ciliary apparatus?

A

Na+
Cl-
HCO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What do the ions do in the ciliary apparatus?

A
  • draw water (osmosis) into the space

- aqueous solution then passed into anterior chamber

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Fluid flows from the anterior chamber into _______________ and then into aqueous veins in the sclera

A

Canal of Schlemm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is normal intraocular pressure?

A

15 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is glaucoma?

A

-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What is the photosensitive pigment in cones?

A

rhodopsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What kind of proteins are photosensitive pigments?

A

transmembrane conjugated proteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What are the 4 major functional segments of rods and cones?

A
  • Outer segment
  • Inner segment
  • Nucleus
  • Synaptic body
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

What major functional segment of rods and cones is the site of light-sensitive photo chemicals?

A

outer segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

What major functional segment of rods and cones connect with horizontal and bipolar cells?

A

synaptic body

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What major functional segment of rods and cones contains organelles (especially mito)?

A

inner segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

What is rhodopsin?

A

Scotopsin + 11-cis retinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Rhodopsin + Light&raquo_space;

A

Scotopsin + All-trans retinal

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

What is 11-cis converted to in the Rhodopsin-Retinal visual cycle?

A

All-trans retinal

Dissociates from rhodopsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

What is Metarhodopsin II?

A
  • intermediate

- excites electrical changes in the rods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What is required to convert All-trans retinal to 11-cis retinal?

A
  • isomerase

- metabolic energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are 2 alternate pathways besides the Rhodopsin-Retinal visual cycle?

A
  • All-trans RETINAL <> All-trans RETINOL (vitaminA)

- All-trans RETINOL <> 11-cis RETINOL <> 11-cis RETINAL

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

What does the excitation of rods cause?

A

increased negativity of the intrarod membrane potential

hyper polarization of rod membrane

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

What does the decomposition of rhodopsin cause?

A

decreased rod membrane conductance for Na+ ions in outer segment

(hyper polarization of rod membrane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Which segment continually pumps Na+ from inside the rod to outside the rod and K+ in the opposite direction?

A

Inner segment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What happens when the outer segment is in the dark?

A
  • Membrane is leaky to Na+
  • Na+ leak into cell, neutralize the inside negativity

**Reduced electronegativity inside the membrane
(-40mV instead of -70 to -80mV)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What happens when the outer segment is in the light?

A

1- Rhodopsin exposed to light = decomposes
2- Retinal portion of rhodopsin complex activated
3- Transducin (G-protein) stimulated
4- cGMP phosphodiesterase activated
5- cGMP&raquo_space; 5’GMP (reduction in cGMP)
6- Na+ channels close
7- Photoreceptor = hyperpolarized

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What are the protein portions of the photo chemicals of cones?

A

opsins

**instead of scotopsin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What are the same in rods and cones?

A

Retinal portions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What colors are cones sensitive to?

A
  • blue
  • green
  • red
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What are the 5 layers of the retina?

A
  • photoreceptors
  • horizontal cells
  • bipolar cells
  • amacrine cells
  • ganglion cells
  • Light
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

Axons going to the brain

A

ganglion cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
50
Q

What do photoreceptors do?

A

-transmit signals to outer plexiform layer

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
51
Q

What is the plexiform layer?

A

layer of synaptic connections

52
Q

What do photoreceptors synapse with?

A
  • bipolar cells

- horizontal cells

53
Q

What do horizontal cells do?

A
  • transmit signals from rods and cones to bipolar cells

- transmit signals to outer plexiform layer

54
Q

Is the horizontal cell output excitatory or inhibitory?

A

ALWAYS INHIBITORY

lateral inhibition

55
Q

What do bipolar cells do?

A
  • transmit signals from rods, cones, and horizontal cells

- transmit signals to inner plexiform layer

56
Q

What do bipolar cells synapse with?

A

amacrine and ganglion cells

57
Q

What do amicrine cells do?

A

transmit signals:
-directly from bipolar to ganglion cells

-within inner plexiform layer (from axons of bipolar cells) to dendrites of ganglion cells/other amacrine cells

58
Q

What do ganglion cells do?

A

transmit signals from retina to brain

59
Q

Axons of the ganglion cells make up ________

A

optic nerves

60
Q

What are the only retina cells that transmit action signals?

A

axons of optic nerves

**others use electronic conduction (allows graded conduction of signal strength)

61
Q

What do the interplexiform cells do?

A

transmit from inner plexiform layer to outer plexiform layer (retrograde)

62
Q

Are interplexiform cells inhibitory or excitatory signals?

A

Inhibitory signals (lateral inhibition)

63
Q

What does the foveal region do?

A

represents a new type of vision based on cone vision

64
Q

What 3 neurons are in direct pathway of the foveal region?

A
  • cones
  • bipolar cells
  • ganglion cells
65
Q

What 4 neurons does pure rod vision consist of?

A
  • rods
  • bipolar cells
  • amacrine cells
  • ganglion cells
66
Q

What nt is needed for rods/comes&raquo_space; bipolar cells?

A

glutamate

67
Q

What are the 8 nt for amacrine cells?

A
  • GABA
  • glycine
  • dopamine
  • Ach
  • indolamine

ALL INHIBITORY

68
Q

What are some of the types of amacrine cells?

A
  • part of the direct pathway for rod conduction
  • responds strongly to onset of continuing visual signal (but fades rapidly)
  • respond strongly at the offset of visual signals (but fades rapidly)
  • respond when a light is turned on/off
  • responds to movement of a spot across the retina in a specific direction
69
Q

Most amacrine cells are _________

A

interneurons that help analyze visual signals before they leave the retina

70
Q

How many rods and cones converge on each ganglion cell and the optic nerve fiber from the ganglion cell?

A

60 rods

2 cones

71
Q

Approaching the fovea, _______ rods and cones converge on each optic fiber and rods and cones become more slender

A

fewer

72
Q

Approaching the fovea, what happens to the visual acuity in the central retina?

A

incrases

73
Q

What are there ONLY in the central fovea?

A

slender cones (35,000)

NO RODS

74
Q

What retina is more sensitive to weak light?

A

peripheral retina

75
Q

How many rods converge on a single optic fiber in peripheral regions of the retina?

A

200 rods

76
Q

What are the 3 types of ganglion cells?

A

WXY

77
Q

What ganglion cells make up 40% of all ganglion cells?

A

W

78
Q

How fast do W ganglion cells transmit signals?

A

8 m/sec

79
Q

W ganglion cell characteristics

A
  • Small

- Receive most of excitation from rods transmitted by way of smaller bipolar cells and amacrine cells

80
Q

Why do W ganglion cells have broad fields in the peripheral retina?

A

Their dendrites spread widely in the inner plexiform layer

81
Q

What ganglion cells make up 55% of all ganglion cells?

A

X

82
Q

How fast do X ganglion cells transmit signals?

A

14 m/sec

83
Q

X ganglion cell characteristics

A
  • Medium diameter
  • Small fields
  • Signals = represent discrete retinal locations
  • Receives input from at least one cone cell (all color vision)
84
Q

What ganglion cells make up 5% of all ganglion cells?

A

Y

85
Q

How fast do Y ganglion cells transmit signals?

A

50 m/sec or faster

86
Q

Y ganglion cell characteristics

A
  • Large diameter (35um)

- Respond to rapid changes in visual image

87
Q

Where does the Dorsal Lateral Geniculate Nucleus receive input from?

A

optic nerve

88
Q

What does the Dorsal Lateral Geniculate Nucleus do?

A
  • Relays information from optic tract to visual cortex using optic radiation (geniculocalcarine tract)
  • High degree of spatial fidelity from retina to the visual cortex
89
Q

What % of decussation in optic chiasm for Dorsal Lateral Geniculate Nucleus?

A

50%

90
Q

What nuclear layers in the Lateral Geniculate Nucleus receive signals from the LATERAL half of ipsilateral retina?

A

2
3
5

91
Q

What nuclear layers in the Lateral Geniculate Nucleus receive signals from the MEDIAL half of the opposite retina?

A

1
4
6

92
Q

What are the Magnocellular layers?

A

1

2

93
Q

What do layers 1 and 2 do?

A
  • Receive input from large Y type ganglion cells

- Provides rapidly conducting pathway to visual cortex

94
Q

Which layers transmit only B&W?

A

1

2

95
Q

Which layers contain large neurons?

A

1

2

96
Q

Which layers have poor point to point transmission?

A

1

2

97
Q

What are the Parvocellular layers?

A

3-6

98
Q

What do layers 3-6 do?

A
  • Receive input from large X type ganglion cells

- Provides moderate conducting pathway to visual cortex

99
Q

Which layers transmit color?

A

3-6

100
Q

Which layers have accurate point to point transmission?

A

3-6

101
Q

What controls how much of the signal is allowed to pass to the cortex?

A

Lateal Geniuclate Nucleus

102
Q

What are the 2 sources of transmission gating control?

A
  • Corticofugal fibers from primary visual cortex
  • Reticular areas of the mesencephalon
  • *BOTH:
  • Inhibitory
  • help highlight visual information that is allowed to pass
103
Q

What is the primary visual cortex also called?

A

Striate cortex

104
Q

Where is the primary visual cortex located?

A

in occipital lobes

105
Q

Where do signals from Macular area terminate?

A

near the occipital pole

106
Q

Where do signals from the more peripheral retina terminate?

A

At or in concentric half circles anterior to the pole but still along the calcarine fissure

107
Q

Where do the geniculocalcarine fibers terminate?

A

Layer 4 of primary visual cortex

108
Q

Which layer do signals from Y ganglion cells terminate?

A

IVca

109
Q

Which layer do signals from X ganglion cells terminate?

A

IVcb and IVa

110
Q

What is the diameter of the primary visual cortex?

A

30-50 um (1000 neurons per column)

111
Q

What are color blobs?

A
  • Special column-like areas

- Among the columns of secondary visual areas

112
Q

What do the color blobs do?

A
  • Receive lateral signals from adjacent visual columns

- Activated specifically by color signals

113
Q

What do signals from the 2 separate eyes enter?

A

alternating stripes of columns in layer 4

114
Q

What deciphers whether the respective areas of the 2 visual images from the 2 eyes are in register with each other?

A

cortical area

115
Q

What is the deciphered information from the 2 eyes used to adjust?

A

the directional gaze of the separate eyes

116
Q

What is cortical area deciphered information also required for?

A

stereopsis

117
Q

In children, refractive power of the lens can be voluntarily increased from _____________

A

20&raquo_space; 34 diopters

accommodation of 14 diopters

118
Q

In young person, what happens to the lens when it is in a relaxed state with no tension on its capsule?

A

assumes spherical shape

119
Q

What creates tension around the lens that causes the lens to remain relatively flat under normal eye conditions?

A

suspensory ligaments

120
Q

What do Meridional fibers of ciliary muscle do?

A

contract and release tension on lens

121
Q

What do Circular fibers of ciliary muscle do?

A

decrease tension on lens

122
Q

Which CN controls both sets of ciliary muscles?

A

CN III

123
Q

What happens to the lens in accommodation in older people?

A
  • becomes larger and thicker with age

- becomes less elastic with age

124
Q

By the age of 45-50 what does the power of accommodation decrease to?

A

<2 diopters

125
Q

By the age of 70 what does the power of accommodation decrease to?

A

0

126
Q

What is the accommodation in older people called?

A

Presbyopia

PHYSIO II Exam #1 - Lo (8 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions