Visual system Flashcards

1
Q

Anatomy of optic pathway:

A

Eye - optic nerve - optic chiasm - optic tract - lateral geniculate nucleus - optic radiation - primary visual cortex (V1)

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2
Q

V1 is located in

A

Occipital love

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3
Q

Where is the lateral geniculate nucleus?

A

Thalamus

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4
Q

What information goes to the left hemisphere?

A

Right visual field from right and left eye

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5
Q

What information goes to right hemisphere?

A

Left visual information from right and left eye

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6
Q

eye can be divided into which regions in terms of visual field?

A

Temporal retina and nasal retina

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7
Q

Nasal retina information

A

Decussates in optic chiasm

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8
Q

Temporal retina information

A

Remains ipsilateral in optic chiasm/ doesn’t cross

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9
Q

Lesion in optic nerve leads to:

A

Monocular blindness in eye of nerve (loss of peripheral vision - keep the part (nasal) which is covered by both eyes)

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10
Q

Lesion at optic chiasm:

A

Bi-temporal hemionopsia (tunnel vision)

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11
Q

What leads to tunnel vision?

A

Losing the temporal fields (carried by nasal fibers)

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12
Q

Another name for tunnel vision =

A

Bi-temporal hemionopsia

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13
Q

Lesion in optic tract =

A

Homonymous hemionopsia on same side

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14
Q

Ex of lesion in optic radiation

A

Meyer’s loop

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15
Q

Meyer’s loop supplies

A

Upper visual field

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16
Q

Lesion in fiber of optic radiation =

A

Quadranopsia

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17
Q

Lesion in occipital lobe =

A

Contralateral homonymous hemianopsia with macular sparing

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18
Q

Why is there macular sparing in occipital lobe lesion?

A

Dual blood supply

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19
Q

3 main layers of eye:

A
  1. Fibrous
  2. Vascular/uvea
  3. Neural
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20
Q

Fibrous layer =

A

Sclera

Cornea

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21
Q

Where do muscles attach?

A

Sclera

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22
Q

Uvea =

A

Choroid
Ciliary body
Iris

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23
Q

Choroid =

A

layer of connective tissue and blood vessels. nourish outer layers of retina

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24
Q

Ciliary body consists of =

A

Ciliary muscles
Ciliary processes
Zonules

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25
Q

Function of ciliary body =

A

Control shape of lens

Formation of aqueous humor

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26
Q

Iris lies between the

A

Lens and cornea

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27
Q

Neural layer =

A

Retina

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28
Q

Center of retina in marked by the

A

Macula and fovea

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29
Q

Fovea =

A

High concentration of photo receptors. Visual acuity

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30
Q

Purpose of eye movements:

A

To move or maintain visual target on fovea (with highest res vision)

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31
Q

Eye movements can be:

A

Conjugate

Disconjugate

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32
Q

Purpose of eye movements can be:

A

Gaze stablising

Gaze shifting

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33
Q

Conjugate eye movements:

A

Vestibulo-ocular
Optokinetic
Saccade
Smooth pursit

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34
Q

Vestibulo-ocular:

A

Gaze stabalisation

Rapid/breif head movement

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35
Q

Optokinetic:

A

Gaze stabalisation

Slow head movements

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36
Q

Saccade:

A

Gaze shifting

Directs eyes towards visual target

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37
Q

Smooth pursuit:

A

Gaze shifting

Follows moving visual target

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38
Q

Disconjugate eye movement and purpose:

A

Vergence

Adjusts eyes for different viewing distance

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39
Q

Extraocular muscles:

A
  • Lateral rectus
  • Medial rectus
  • Superior rectus
  • Inferior rectus
  • Superior oblique
  • Inferior oblique
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40
Q

SO4 LR6

A

Superior oblique 4

Lateral rectus 6

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41
Q

Elevation by

A

Superior rectus

Inferior oblique

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42
Q

Depression by

A

Inferior rectus

Superior oblique

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43
Q

Intorsion by

A

Superior rectus

Superior oblique

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44
Q

Extorsion by

A

Inferior rectus

Infectior oblique

45
Q

Adduction by

A

Medial rectus

46
Q

Abduction by

A

Lateral rectus

47
Q

Zonules =

A

Attach cilliary body to lens

48
Q

Muscles within what help the pupil to change size

A

Iris

49
Q

Pupil constriction =

A

Miosis

50
Q

Pupil dilation =

A

Mydriasis

51
Q

Miosis what is active and relaxed

A

Iris sphincter

Dilator relaxed

52
Q

Miosis is under what control

A

Parasympathetic (relaxed state)

53
Q

Mydriasis is under what control

A

Sympathetic

54
Q

Tropicamide:

A

Anti-muscarinic, causes dilation

55
Q

Atropine:

A

anti-muscarinic: causes dilation

56
Q

Condition in which 2 pupils are different sizes =

A

Anisocoria

57
Q

Where does ocular motor nerve originate in brainstem?

A

Edinger-Westphal nucleus

58
Q

Ocular motor nerve carries what innervation

A

Parasympathetic to sphincter

59
Q

Synapse of oculomotor n =

A

Cilliary ganglion

Short cillary nerve

60
Q

What nerve carries innervation to dilator muscle?

A

Opthalmic nerve (V1)

61
Q

When an object is distant, light rays are what so lense is what

A

Parallel

Flatter

62
Q

When an object is near, light rays are what so lense is what

A

Diverging

Rounder

63
Q

Accommodation reflex =

A

Focus on near objects

64
Q

Accommodation reflex is under what control?

A

Parasympathetic control

65
Q

Where is aqueous humor located primarily?

A

Anterior chamber

66
Q

Function of aqueous humor

A
  • Nourishment to outer layers
  • Intraocular pressure
  • Vitamin C to front (antioxidant)
  • Protection against dust and wind
67
Q

What drains aqueous humour

A

Trabecular meshwork

Schlemm’s canal

68
Q

2 main types of blood flow:

A
  1. Retinal artery

2. Choroid

69
Q

World-leading causes of blindness:

A
  • Cataracts
  • Uncorrected refractive error
  • Glaucoma
  • Age-related macular degeneration
  • Diabetic retinopathy
  • Corneal opacities
70
Q

Cataracts effect which part of the eye?

A

Lens

71
Q

Cataracts -

A

Opacification of lense caused by compaction and protein deposition.

72
Q

Risk factors for cataracts:

A
  • Age
  • Traume
  • Diabetes
  • Smoking
  • UVB light
  • Genetic
73
Q

Treatment of catracts:

A

Outpatient surgery, lense removed and replaced with artificial

74
Q

Glaucoma:

A

Group of eye diseases in which optic nerve is damaged by pressure inside eye

75
Q

Risk factors of glaucoma:

A
  • Age
  • Recent surgery or trauma
  • High IOP
  • High BP
  • Severe myopia
  • Long-term corticosteroid use
76
Q

2 types of glaucoma:

A

Primary open angle

Acute closed angle

77
Q

Which type of glaucoma is more common and chronic?

A

Primary open angle

78
Q

Cause of primary open angle glaucoma:

A

BLockage of trabecular meshwork

79
Q

Symptoms of primary open angle glaucoma:

A

Gradual loss of vision starting in peripheries

80
Q

Cause of acute closed angle glaucoma

A

Iris bows, closes the antierior chamber angle and blocks drainage

81
Q

Symptoms of acute closed angle glaucoma:

A
Sudden, severe stabbing pain
Sudden vision loss
Red eye
Head pain
Nausea/vomiting
82
Q

3 tests for glaucoma

A

Tonometry - measure IOP
Peripheral fields
Fundus photography

83
Q

What might you see in fundus photography in a patient with glaucoma?

A

Cupping

84
Q

Treatments for glaucoma:

A
  • Reduce aqueous humor: beta blockers, alpha blockers, carbonic anhydrase inhibitors.
  • Increase trabecular outflow: muscarinic agonists
  • Increase uveoscleral outflow: prostaglandin agonists
85
Q

Pilocarpine:

A

Muscarinic agonist

86
Q

Ex of beta-blocker

A

Betatoxolol

87
Q

Retinal cell types in order:

A

Ganglion cells - Biopolar cells + horizontal cells - photoreceptors, rods and cones - pigmented epithelium

88
Q

Cones:

A

High density in fovea
Daytime vision
Colour (red, green, blue)

89
Q

Which cone detects highest wavelength

A

Red

90
Q

Rods:

A

Non in center, lots outside center
Night vision
Very sensitive to light
Grey scale

91
Q

Which photoreceptor is most sensitive to light?

A

Rods

92
Q

Red/green colour blindness is what (genetic)

A

X linked

93
Q

Blue colour blindness is what (genetic)

A

Chromosome 7

94
Q

Only have 2 cone types =

A

Dichromats

95
Q

Protanopes
Deuteranopes
Tritanopes

A

No Red
No Green
No Blue

96
Q

Have 3 cone types but sensitivity of one is shifted towards others:

A

Anomalous trichromats

97
Q

Protanomalous trichromat
Deuteranomalous trichromat
Tritanomalous trichromat

A

Red shifted
Green shifted
Blue shifted

98
Q

Information from fovea is processed where in occipital lobe?

A

Back

99
Q

Information from peripheral is proccessed where in occipital lobe?

A

Anteiror

100
Q

V4

A

Colour

101
Q

V5

A

Motion

102
Q

Problem with V4 can cause:

A

Achromatopsia

103
Q

Problem with V5 can cause:

A

Akinetopsia

104
Q

‘where’ pathway - what lobe

A

Posterior-parietal cortex

105
Q

‘what’ pathway - what lobe

A

Inferio-temporal

106
Q

Lesion to dorsal stem/posterior parietal lobe =

A

Optic ataxia

107
Q

Lesion of ventral stem/inferior temporal lobe =

A

Visual agnosia

108
Q

Visual agnosia =

A

The man who mistook his wife for a hat!