Brainscape's Knowledge GenomeTM

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


See full index

MS1 Neuroscience > Eye Parts > Flashcards

Eye Parts Flashcards

1
Q

Sclera

A

White dense connective tissue that covers the globe posterior to the cornea. It provided attachment for extraocular muscles and the ciliary muscle

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

Cornea

A

mechanically strong and transparent connective tissue. The most powerful focusing element of the eye, twice as powerful as the lense.

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

Lens

A

Transparent epithelial tissue that fine tunes the image projected on the retina

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

Choroid

A

Capillary bed nourishing the photoreceptors and outer retina

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

Ciliary muscle

A

controls the refractive power of the lens

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

Ciliary Epithelium

A

produces the aqueous humor filling the anterior chamber

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

Iris

A

controls size of the pupil

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

Vitreous humor

A

Thick gelatinous substance filling the space btw the back of the lens and the surface of the retina

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

Retina

A

contains neurons that absorb light and process visual information

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

Macula

A

oval spot containing a yellowish pigment. Supports high acuity

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

fovea

A

small depression at the center of the macula

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

optic disk

A

where retinal axons leave the eye, and where blood vessels supplying the inner retina enter the eye

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

Retinal supply

A

Delivery of metabolic substrates and oxygen by the inner retinal vascular system and choroidal vascular system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Myopia

A

nearsightedness
eyeball is too long (cornea is too curved)
can focus clearly on objects closer to the eye
fixed with concave lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Hyperopia

A

farsightedness
eyeball is too short (cornea is not curved enough)
can focus clearly on objects far from the eye
fixed with convex lens

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Positive lens

A

convex

moves the focal point foward

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

Negative lens

A

concave

moves the focal point further from the lens

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

Presbyopia

A

lens enlarges and becomes denser and more rigid. Losses ability to accommodate.

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

Scotoma

A

a portion of the Visual Field that is missing

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

Arcuate

A

arc-like shape defect produced by retinal nerve fiber bundle damage

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

Altitudinal

A

superior or inferior defect that splits horizontally

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

Hemianopia

A

nasal or temporal defect that splits vertically

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

Quadrantopia

A

defect that affects one quarter

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

Cataracts

A
  • clouding of the lens due to disruption of the organization of the lens cell fibers or aggregation of the proteins.
  • leading cause of blindness
  • need surgical removal of the cloudy lens and replacement with an artificial one
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Accommodation

A
  • contraction of the ciliary muscle cause reduced tension of the zonule fibers which allows the lens to thicken.
  • increased lens curvature decreases the focal length
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Open- Angle Glaucoma

A
  • slow development of pathology

- obstruction of drainage canals causes pressure to build in the anterior chamber

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

Closed -Angle Glaucoma

A
  • Sudden increase in intraocular pressure (IOP)

- Closed or narrow angle btw the iris and the cornea

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

Glaucoma General Symptoms and Treatment

A

Symptoms: Non until its too late, decreased peripheral vision

Treatment: Eye drops to decrease aqueous production and/or increase drainage, or surgery

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

Layers of the retina

A 
light comes through the: 
1) nerve fiber layer
2) Ganglion Cell Layer
3) Inner plexiform layer
4) Inner nuclear layer
5) Outer plexiform layer
6) Outer nuclear layer
and then reaches the Photoreceptor outer segment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

lateral information flow in the retina

A

mediated by horizontal and amacrine cells (release GABA or Glycine)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

vertical information flow in the retina

A

photoreceptors to bipolar cells to ganglion cells (release Glutamate)

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

pigmented epithelium

A

melanin containing cells behind the photoreceptors that maintain phototransduction machinery.

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

Photoreceptor structure

A

Outer segment - phototransduction machinery
Cillium- connects the outer to inner segment
Inner segment- housekeeping machinery
Synaptic terminal- contacts bipolar and horizontal cells and uses glutamate

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

Photoreceptors in the dark vs light

A

Photoreceptor in depolarized in the dark and continually releasing glutamate

When light contacts the photoreceptor it causes a graded hyperpolarization and it decreases the release of glutamate.

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

Photoreceptors in the Dark

A

1) constant current with Na+ & Ca+ flowing in to depolarize the cell (occurs in the outer segment)
2) K+ current flowing out to hyperpolarize the cell (occurs in the inner segment)

the two actions combine to create a steady sight depolarized membrane potential around -40 mV

36
Q

Photoreceptors in the Light

A

1) light absorption decreases cGMP levels in the (outer segment)
2) Na+ and Ca2+ channels are cGMP gated so they shut down
3) the K + channels are fine so the K+ keeps flowing out and hyperpolarizes the cell
4) Since the cell is hyperpolarized the release of glutamate decreases.

37
Q

Phototransduction steps

A

1) Absorption of a photon changes the conformation of retinal 11-cis (inside the opsin molecule) to 11-trans
2) this is then able to activate rhodopsin (R to R)
3) R catalyzes the activation of heterotrimeric G-protein known as transducin
4) this decreases cGMP

38
Q

Dark Adaptation

A

1) Once 11-cis retinal has absorbed the photon and transformed into 11-trans it dissociates from the opsin
2) 11- trans retinal is transported to the pigment epithelium where it is converted back to 11- cis retinal
3) 11-cis is transportd back to recombine with opsin

39
Q

fovea

A

small depression at the center of the macula which is mainly populated by cones.

Has 0.01% of the retinal area and uses 10 to 50% of the optic nerve

40
Q

Scotopic

A

rod only vision

41
Q

Photopic

A

cone only vision

42
Q

mesopic

A

normal vision

43
Q

Retinitis Pigmentosa (RP)

A
  • Genetic, leads to incurable blindness
  • Caused by mutations of genes for rhodopsin & other rod protein, leading to degeneration of rods and eventually cones

Symptoms:
night blindness, tunnel vision, legally blind by 40

Diagnosis:
loss of ERG

Treatment:
None

44
Q

ERG

A

Electroretinogram - record electrical activity of the eye after a large field flash of light

45
Q

AMD, symptoms and risk factors

A

Age-related Macular Degeneration
leading cause of vision loss

Symptoms:
Loss of central vision and acuity

Risk Factors:
ageing, smoking, inheritance

46
Q

Wet form AMD

A

Abnormal blood vessels behind the retina grow under the macula, leaking and rapidly damaging the retina

Treatment:
lazer coagulation of vessels and intravitreal injection of anti-neovascular agents

47
Q

Dry form AMD

A
  • accounts for 85% of cases
  • RPE & photoreceptors of the macula degenerate
  • Accumulation of drusen (yellow deposits)

Treatment:
Antioxidants

48
Q

Non-proliferative Diabetic Retinopathy

A

Hyperglycemia-inducted pericyte death leads to incompetence of vascular walls, micro-aneurysms & “dot and blot” hemorrhages

49
Q

Proliferative Diabetic Reintopathy

A

New fragile vessels grow, which leak blood

50
Q

Diabetic Retinopathy, risk, symptoms, and treatment

A

Risk:
Up to 80% in people who have had diabetes for 10+ yrs

Symptoms:
Early stage has no symptoms, late stage has blurry vision with macular edema.

Treatment:
Lazer surgery to reduce edema and injections with anti-neovascular factors

51
Q

sign invert synapse

A

for on-center bipolar cells

- have metabotropic receptors that hyperpolarize (cation channels close) in response to glutamate

52
Q

sign conserving synapse

A

for off-center bipolar cells

-have ionotropic receptors, cells depolarize (cation channels open) in response to glutamate

53
Q

cone opsins

A

member of the G-protein coupled receptor family

-the opsin sequence tunes the absorption of light to a particular region of the spectrum

54
Q

protanope

A

No L cones

55
Q

deuteranope

A

No M cones

56
Q

Tritanopia

A

No S cones

57
Q

M cells

A
  • large receptive fields
  • good light, motion, and contrast sensitivity
  • Origin of the magnocellular pathway
58
Q

P cells

A
  • also called midget cells
  • small receptive fields
  • high acuity and color sensitivity
  • origin of parvocellular pathway
59
Q

K cells

A
  • bi-stratified ganglion cells

- carry short wavelength info

60
Q

Intrinsically photosensitive retinal ganglion cells

A
  • contain the primitive opsin
  • autonomous response to bright lights

Roles:

1) Inform ambient light intensity
2) Synchronize circadian rhythms
3) Control Pupil resonse

61
Q

Tangent Screen

A

an instrument for determining the integrity of the central field of vision

62
Q

Goldman Perimeter

A
  • hollow white sphere a set distance from the pt

- Examiner moves a test light of variable size and intensity

63
Q

Humphrey Perimeter

A

-Goldman perimeter but done by a computer

64
Q

Complete/ incomplete VFD

A

extension of type of defect

65
Q

relative/ absolute

A

to the type of stimuli

66
Q

Homonymous

A

the defect is the same side for both eyes

67
Q

Heteronymous

A

the defect is in different sides

68
Q

Congruous

A

the defect is similar in both eyes

69
Q

incongruous

A

the defect is different in both eyes

70
Q

retina VFD

A

general defects, arcuate in glaucoma, central scotoma in foveal lesion

71
Q

Optic Nerve VFD

A

can product any type of defect

including alititudinal field defect

72
Q

Optic Chiasm VFD

A
  • usually caused by tumors, or carotid aneurysms

- usually bitemporal field defect

73
Q

Optic tract VFD

A

Homonymous and incongruous ( the more posterior the more congruous it becomes)

74
Q

Lateral Geniculate VFD

A

usually congruous sectoranopia, or incongruous hemianopia

75
Q

Temporal VFD

A

superior homonymous quadrantanopia

76
Q

Parietal VFD

A

inferior homonymous quadrantanopia

77
Q

Calcarine cortex VFD

A

macular sparring

78
Q

cortical magnification

A

mapping in the visual cortex is proportional to the density of photoreceptors, not the area of the visual field.

79
Q

cone opponency

A

any single cone type cannot inform about both intensity and wavelength by itself

80
Q

Neocortex

A

2&3- output to high level cortical targets (Ex. V1 toV2)
4- input from lower layers
5- output to subcortical targets (Ex. Superior Colliculus)
6- input from higher levels (Ex. cortex)

81
Q

lateralized lesion in parietal cortex

A

hemispatial neglect

82
Q

prosopagnosia

A

inability to recognize faces, from lesions in certain parts of the temporal cortex

83
Q

amblyopia

A

one eye is weaker in the brain

use patching of the strong eye to fix

84
Q

Strabismus

A

improper alignment of the eyes

if you have alternation strabismus, your brain has two strong eyes and has to switch btw them

85
Q

Hebbian Mechanisms

A

Cells that fire together, wire together

- explains how in amblyopia one eye can take over the brain

MS1 Neuroscience (3 decks)

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