Brainscape's Knowledge GenomeTM

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


See full index

P2 Head, Neck and Neuro > Eileen - eye, visual pathways, age related macular degeneration > Flashcards

Eileen - eye, visual pathways, age related macular degeneration Flashcards

1
Q

What is the definition of sightlessness?

A

Having less than 1/10 of normal vision in the more efficient eye when refractive problems are fully corrected

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

What develops in retinopathy?

A
  • Microaneurysms
  • Neovascularisation
  • Heamorrhage
  • Retinal opacities
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How do micro-aneurysms appear?

A

Outpouring of the retinal vasculature that appear as minute, unchanging red dots associated with blood vessels

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

How do micro-aneurysms occlude vision?

A
  • Leak plasma, resulting in localised oedema that gives the retina a hazy appearance
  • They also bleed - contributing to oedema
  • Affected vision if they encroach on the macula and cause degeneration before they are absorbed
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

How does neovascularisation occur?

A

Formation of new blood vessels from the choriocapillaries, entering between the pigment and sensory layer, or from the retinal veins, extending between the sensory retina and vitreous cavity and sometimes into the vitreous body - growth factors, signalling systems and VEGF involved

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

How can neovascularisation causes problems with sight?

A

The vessel are fragile, lead protein and are likely to bleed- blurred vision if covers the macular and can cause degeneration

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

What are opacities?

A

Loss of retinal transparency due to haemorrhages, exudates, cotton wool spots, oedema and tissue proliferation - exudate result from inflammatory processes

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

How do exudate damage vision?

A

Destroy the underlying retinal pigment and choroid layer

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

What are cotton wool patches?

A

Retinal opacities with hazy irregular outlines

These occur in the nerve fibre layer and contain cell organelles

Associated with

  • retinal trauma
  • severe anaemia
  • papillodema
  • diabetic retinopathy
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the investigations that can be done to diagnose age related macular degeneration?

A

Funds fluorescein angiogram

  • IV fluorescein injection
  • fluorescein binds to albumin which remains in normal capillaries
  • use blue and yellow filter to see details of retinal circulation

Optical coherence tomography

  • low power laser interferometry
  • generates detailed cross-section image of retina
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Name and describe the two types of AMD.

A

Exudative - new blood vessel formation under retina/above choroid

  • rapid
  • metamorphopsia

Atrophic

  • atrophy of the outer retina
  • slow
  • blurring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How does AMD cause blindness?

A

Blood vessels and scar tissue grow under the retina

Leaking vessels cause retinal oedema

This blocks transport of oxygen and nutrients from the choroid to the avascular macular

Eventual scarring causes destruction of photoreceptors

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

What are the risk factors for AMD?

A
  • Smoking
  • Age (over 70)
  • Diet - high doses of vitamin A, C and zinc may be protective
  • Family history
  • Genetics
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What’s the most common genetic cause of AMD?

A

Polymorphism sin complement factor H gene- regulates inflammation and prevents complement mediated attach on own cells - inflammation is significant in AMD

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

What are other genes that are thought to cause AMD?

A
  • Complement genes - CFB, CF1, C2 and C3
  • Lipids - genes for LDL and HDL
  • ECM - collagen and matrix metalloproteinase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is thought to start the process of AMD?

A

Photoreceptors continue to produce photosensitive pigment throughout life

The ends of photoreceptor cells decay and are removed by retinal pigment epithelium constantly

  • in some cases the end products accumulate causing drusen
  • increases AMD risk
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the best treatment for AMD?

A

Monoclonal antibodies that inhibit VEGF - to prevent neovascularisation

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

What are the licensed and unlicensed treatments for AMD?

A
  • Ranibizumab - licensed (more expensive)
  • Bevacizumab - unlicensed (less expensive)

Both are anti-VEGF drugs given locally via intravitreal injections

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

How is ranibizumab administered?

A

Intravitreal injection by opthalmologists in a sterile room

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

How often is ranibizumab administered?

A

Once a month for three months

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

How many people on ranibizumab improved?

A

40% improved by 15 or more letters on a visual acuity test

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

What are the differences between ranibizumab and bevacizumab?

A
  • Injections given as required, not every month
  • Yearly cost of R=£9656 while B=£1509
  • Same improvements
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are the economic problems or blindness?

A
  • Unable to work - loss of employment and income
  • Requires increased care - more likely to be put in a nursing home
  • Finance - bank statements and bills
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What are the problems people with independence that blind people have?

A
  • Health risks - falls and fractures
  • Domestic - cooking, eating, dressing and telephone
  • Shopping
  • Navigation - safety
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What are the problems with communication people with blindness have?

A
  • Hearing impairment
  • Non-verbal communication
  • Social interactions
  • TV, film and media
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What are the psychological problems people with blindness have?

A
  • Depression
  • Anxiety
  • Increased isolation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What is visual acuity?

A

Recorded as: the distance chart is read/distance at which it should be read

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

What measures must be made when checking visual acuity?

A

Check if the patients need distance glasses - get them to wear them

6 meters from the chart

One eye at a time, if vision is imperfect - use a pinhole

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

What extra tests should be done is the recorded vision is less than 6/60?

A
  • Count finger
  • Hand motions
  • Light perception
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What information do the rods in the eyes pass to the CNS?

A

They tell the CNS about the absence or presence of photons without regard to wavelength

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

Where does the transduction of light energy into a receptor potential occur in the photoreceptors?

A

The outer segments of both rods and cones

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

Describe the plasma membrane in the outer segment of the cones.

A

Folds back and forth in a pleated fashion

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

Describe the plasma membrane in the outer segment of the rods.

A

The pleats formed pinch off from the plasma membrane to form discs - around 1000 stacked discs piled in each outer segment

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

How are the outer segments of the rods renewed?

A

One to three new discs are added to the base each hour, while old discs are court off the tip and phagocytosed by pigment epithelial cells

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

What is contained in the inner segment of the photoreceptors?

A
  • Mitochondria
  • Golgi complex
  • Nucleus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Describe the proximal end of the photoreceptors.

A

Expands into a bulblike synaptic terminal filled with synaptic vesicles

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

What is the first step in signal transduction?

A

Absorption of light by a photopigment

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

What is a photopigment?

A

A coloured protein that undergoes structural changes when it absorbs light in the outer segment

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

What is the photopigment found in rods?

A

Rhodopsin

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

What are the photopigments in the outer section of the cones?

A

Three different types - one for each colour - colour vision comes from selective activation of these pigments

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

What do all photopigments in the eye have in common?

A

Their two constituent parts- Opsin (glycoprotein)- retinal (pigment)

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

Out of retinal and Opsin, which part of photopigments varies depending on cone colour or rod?

A

Opsin (4 different types)- small variations in amino acid sequence of the different opsins permit the rods and cones to absorb different wavelengths of light

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

Describe retinal.

A

Vitamin A derivative formed from caroteneThis is the light absorbing party of all visual photopigments

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

What is the shape of retinal in darkness?

A

Retinal has a bent (cis-retinal) shape which fits into the opsin portion of the photoreceptor

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

What happens to cis-retinal when it absorbs a photon of light?

A

It undergoes isomerisation - where it straightens out to become trans-retinal

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

What happens after isomerisation of trans-retinal?

A

Several unstable chemical intermediates form and disappear - leading to the production of a receptor potential

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

What happens to the retinal after it has been straightened.

A

It detaches from the opsin in a method known as bleaching (because the final products look colourless)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the function of retinal isomerase?

A

It converts trans-retinal back into cis-retinal, so it can bind to opsin (reforming a functional photopigment) in a process called regeneration

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
49
Q

How does the pigmented area contribute to regeneration?

A

It stores a large quantity of vitamin A for the retinal in the rods

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

Describe the release of neurotransmitters by the photoreceptors in darkness.

A

1) cGMP gated sodium channels open 2) sodium influx 3) membrane potential increases (partial depolarisation) 4) causes constant glutamate release at the synaptic terminals and inhibition of the bipolar cells

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

Describe neurotransmitter release during light transduction.

A

1) isomerisation of retinal activates an enzyme that breaks down cGMP2) cGMP gated sodium channels close 3) sodium inflow slows down4) hyperpolarisation induces a receptor potential 5) this turns off neurotransmitter release, exciting the bipolar cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
52
Q

What happens to glutamate release in dim light?

A

Small and brief receptor potentials are activated that only partially turn off glutamate release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
53
Q

How many rods synapses with a single bipolar cell?

A

6-600 depending on the area - this increases the light sensitivity of rod vision, but slightly blurs the perceived image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
54
Q

How many bipolar cells do cones synapse to?

A

Normally just one- this is less sensitive to light, but yields a sharper image

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
55
Q

What happens to the cone bipolar cells when light enters the eye?

A

They can either be excited or inhibited depending on the cone they are attached to

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
56
Q

What is the function of the lateral inhibitions by horizontal cells?

A

It sends inhibitory signal a to bipolar cells in the area lateral to the excited rods and conesIt does this because it enhances contrast of the visual scene between the areas that are strongly stimulate and adjacent areas that are more weakly stimulated

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
57
Q

What do amacrine cells do?

A

These are excited by bipolar cells, synapse with ganglion cells and transmit information to them that signals a change in the level of illumination of the retinaThis (and excitement of the bipolar cells) depolarises the ganglion cells and initiate nerve impulses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
58
Q

Where do the axons of the optic nerve terminate?

A

In the lateral geniculate nucleus of the thalamus

59
Q

What does the optic nerve axons synapse with in the lateral geniculate nucleus?

A

Neurons whose axons form the optic radiations

60
Q

Where do the optic radiation a project to?

A

The primary visual areas in the occipital lobes and visual perception begins

61
Q

What are some of the other fibres in the optic tract that synapse with the optic nerve in the lateral geniculate nucleus of the thalamus?

A

Some project to the superior colliculus - control extrinsic eye musclesOther projects to the pretectal nucleus - controls pupillary and accommodation reflexes

62
Q

What is a visual field?

A

Everything that can be seen by one eye- the two visual fields overlap considerably

63
Q

What are the two regions the visual field can be divided into?

A

Nasal and temporal halves (A.k.a. Central and peripheral halves)

64
Q

Where do light rays from the nasal and temporal parts of the visual field fall in the retina?

A

Light from the nasal part of the visual field falls on the temporal part of the retinaVice versa

65
Q

Which side of the brain does visual information from the right half of each visual field travel?

A

The left

66
Q

Which side of the brain does visual information from the left half of the visual field travel to?

A

The right side

67
Q

At the optic chiasm, what happens to axons from the temporal half of the retina?

A

They do not cross

68
Q

At the optic chiasm, what happens to axons from the nasal half of the retina?

A

They cross the optic chiasm and travel to the opposite side of the brain for interpretation

69
Q

What are the things processed by different systems to produce visual signals?

A

Shape of objectsColour of objectsMovement, location and spatial organisation

70
Q

What are the three layers of the eye?

A

RetinaFibrous tunicVascular tunic

71
Q

What are the layers of the fibrous tunic?

A

Superficial layerAnterior cornea Posterior sclera Junction of sclera and cornea

72
Q

Describe the cornea.

A

Transparent coat that covers the iris Curved to help focus light on the retina The central parts of the cornea receives oxygen from the outside air - contacts must be permeable to allow oxygen through them

73
Q

Describe the components of each layer of the cornea.

A

Outer surface consists of non-keratinised stratified squamous epitheliumMiddle coat - collagen fibres and fibroblasts Inner coat - simple squamous epithelium

74
Q

Describe the sclera.

A

The white of the eyeA layer of dense connective tissue composed of collagen fibres and fibroblasts Covers the whole eye ball except the cornea - gives the eyeball shape and makes it rigid (protects the inner parts)An attachment site for extrinsic eye muscles

75
Q

What is found in the junction of the sclera and cornea?

A

Sclera like venous sinus - aqueous humour drain into this

76
Q

What is the function of the fibrous tunic?

A

Mechanical support and physical protectionAttachment site for extrinsic eye musclesAssists focusing

77
Q

What are the components of the vascular tunic?

A

ChoroidCiliary bodyIris

78
Q

What is the most posterior part of the vascular tunic?

A

Choroid

79
Q

Where is the choroid in relation to the sclera?

A

Lines the internal surface of the sclera

80
Q

Why does the choroid appear dark brown?

A

Contains melanocytes that produce high quantities of melanin

81
Q

Why does the choroid contain such high quantities of melanin?

A

So it absorbs lots of light rays, preventing reflection and scattering of the light within the eyeball- causing the image to be cast on the retina by the cornea to remain sharp and clear

82
Q

What happens to the choroid in the anterior portion of the vascular tunic?

A

It becomes the ciliary body

83
Q

Where is the ciliary body?

A

It extends from the jagged anterior margin of the retina (or a serrata) to just posterior to the junction of the sclera and cornea

84
Q

What are the two parts of the ciliary body?

A

Ciliary processes and ciliary muscle

85
Q

Describe the ciliary processes

A

Protrusions or folds in the inner surface of the ciliary body Contains blood capillaries that secrete aqueous humour

86
Q

What are zonular fibres?

A

Fibres that extend from the ciliary process to the lens The fibres consists of thin, hollow fibrils that resemble elastic connective tissues fibres

87
Q

What is the ciliary muscle, and what is its function?

A

Circular band of smooth muscleContraction and relaxation of this muscle changes the tightness of the zonular fibres, which alters the shape of the lens, adjusting it for near or far vision

88
Q

Where is the iris located?

A

Suspended between the cornea and the lens attached to the ciliary processes on its outer margin

89
Q

What does the iris contain?

A

Blood vesselsPigment cellsLoose connective tissueCircular and radical smooth muscle fibres Melanocytes

90
Q

What does the amount of melanin in the iris dictate?

A

Eye colour- large amounts of melanin = brown or black eyes- moderate amounts of melanin = green eyes- low amounts of melanin = blue eyes

91
Q

What is the function of the iris?

A

Regulates the amount of light entering the eyeball through the pupil

92
Q

Why does the pupil appear black?

A

It shows the inside of the eye- heavily pigmented choroid and retina can be seen

93
Q

Why is light reflected (e.g. In photos) from the eyeballs seen to be red?

A

Blood vessels on the surface of the retina

94
Q

When bright light stimulates the eye, what happens to the pupil, and how?

A

Parasympathetic fibres of CN III stimulate the circular muscles (sphincter pupillae) of the iris to contract Pupil constriction occurs

95
Q

When dim light simulates the eye, what happens to the pupil, and how?

A

Sympathetic nerves stimulates the radical muscle (dilator pupillae) of the iris to contractThe pupil becomes dilated

96
Q

What enters and leaves the eye at the optic disc?

A

Optic nerveCentral retinal artery (branch of the ophthalmic artery)Central retinal vein

97
Q

What is the name of the two layers of the retina?

A

Pigmented layerNeural layer

98
Q

What is the pigmented layer of the retina, and where is it located?

A

A sheet of melanin-containing epithelial cells found between the choroid and the neural part of the retina

99
Q

What is the function of the pigmented layer of the retina?

A

Melanin in this layer helps absorb stray rays of light

100
Q

What is the neural layer of the retina?

A

Multilayered outgrowth of the brain

101
Q

What is the function of the neural layer of the retina?

A

Processes visual data extensively before sending nerve impulses into the axons that form the optic nerve

102
Q

What are the three layers that form the neural part of the retina?

A

Photoreceptive layerBipolar cell layerGanglion cell layer

103
Q

What are the two zones that separated the three layers of the neural part of the retina?

A

Outer an inner synaptic layers

104
Q

Which order does light pass through the neural layer of the retina?

A

Ganglion cell layerInner synaptic layerBipolar cell layerOuter synaptic layer Photoreceptive layer

105
Q

Name the two other cell types present in the bipolar layer, and what do they do?

A

Amacrine cells Horizontal cellsThey regulate communications between the rods/cones and ganglion cells- helps adjust retinal sensitivity to dim/bright light- changes the contrast

106
Q

List the order of the layers from the outer layer of the eye, to the optic nerve axons on the inside.

A

Sclera Choroid Pigmented layer of the retinaPhotoreceptive layer of the neural layer of the retinaBipolar cell layer of the neural layer of the retinaGanglion cell layer of the neural layer of the retinaOptic nerve axons

107
Q

What are the two types of photoreceptors?

A

Cones and rods

108
Q

What is the function of the rods?

A

Allow vision in dim light (no colour vision) - black, white and all shades of grey - very light sensitive

109
Q

What is the function of the cones?

A

Stimulates by brighter lights - three types of cones = red, green and blue - various combinations of these cones result in colour vision - gives sharper and clearer images- doesn’t see as well in dim light

110
Q

Describe the cone and rod distribution of the eye.

A

Cones are found in greater concentrations at the back of the eye, and rods are found round the sides

111
Q

What is the area of the eye with the highest concentration of cones called?

A

The macular densa

112
Q

Define optic disc

A

Is the point of exit for ganglion cell axons leaving the eye.

Contains no cones or rods -> physiological blind spot

113
Q

Describe the fovea centralis

A

A small depression in the centre of the macular densa which contains only cones - area of highest visual acuity

114
Q

What makes up the refractive media of the lens?

A

Proteins called crystalline within the lens- arranged like layers in an onion - perfectly clear and transparent

115
Q

What is the outer covering of the lens?

A

Clear connective tissue

116
Q

What is the function of the lens?

A

Helps the focus the image on the retina by changing its own shape- facilitates clear vision

117
Q

What are the two cavities within the eyeball called?

A

The anterior and posterior cavity (or vitreous chamber)

118
Q

What are the two chambers within the anterior cavity?

A

Anterior and posterior chambers

119
Q

Where is the anterior chamber?

A

Between the cornea and the iris

120
Q

Where is the posterior chamber?

A

Between the iris and the zonular fibres and lens

121
Q

What is the contents of the anterior cavity?

A

Aqueous humour - transparent watery fluid which nourishes the lens and the cornea

122
Q

How does the aqueous fluid enter and leave the anterior cavity?

A

Continually filters out from capillaries in the ciliary processes of the ciliary body - entering the posterior chamber It flows between the iris and the lens, through the pupil and into the anterior chamberIt then drains into the scleral venous sinus from the anterior chamber and into the blood

123
Q

How often is aqueous humour replaced?

A

Completely replaced every 90 minutes

124
Q

Where is the vitreous chamber?

A

Between the lens and the retina

125
Q

Describe the vitreous fluid, and it’s function.

A

A transparent jelly-like substance that holds to retina flush against the choroid - gives the retina an even surface for the reception of clear images

126
Q

What are the components of the vitreous body?

A

Water, collagen fibres, hyaluronic acid and phagocytes (to keep this part of the eye free from debris for uninterrupted vision)

127
Q

What is the hyaloid canal?

A

A narrow channel (inconspicuous in adults) that runs through the vitreous body from the optic disk to the posterior aspect of the lens

128
Q

What is the pressure in the eye called, and what is it normally?

A

The intraocular pressure is normally 16mmHg

129
Q

Which component on the eye produces the intraocular pressure, and why is it needed?

A

The pressure is mainly produced by the aqueous humour and only partly by the vitreous body.It’s needed to maintain the shape of the eyeball and prevent collapse

130
Q

Describe the anatomy of the eye

A
131
Q

Describe the histology of the macula

A
  • Central section = fovea
  • Fovea contains NO rods, only CONE photoreceptors -> colour + detailed vision
  • NO blood vessels - dependant on choroid for O2 & metabolic support
132
Q

What investigations are proposed by a macular clinic when AMD is suspected?

A
  1. Visual acuity
  2. Metamorphopsia (when a group of straight lines look wavy)
  3. Dilated fundus exam
  4. Fundus fluoro angiogram (inject IV fluroscein -> binds to albumin -> should remain within normal capillaries because of blood-brain barrier
  5. Optical coherence tomography - detailed cross section of retina
133
Q

What’s the diagnosis of this swinging flash light test?

A

Left occulomotor damage

134
Q

What’s the diagnosis of this swinging flash light test?

A

Normal

135
Q

What’s the diagnosis of this swinging flash light test?

A

Right optic nerve damage

136
Q

What’s the diagnosis of this swinging flash light test?

A

Right optic & occulomotor damage

137
Q

Describe the neural pathway for light reflex

A

Transmitted light rays focused onto retina -> retinal photoreceptors transduce light energy into changes in neuronal membrane potential -> signals transmitted to brain via optic nerve.

  1. Optic Chiasm
  2. Optic Nerve
  3. Optic Tract
  4. Lateral Geniculate Nucleus
  5. Optic Radiations
  6. Visual Cortex
  7. Midbrain
  8. Pituitary Stalk
138
Q

What is the role of the visual pathway?

A

To relay visual field info from both eyes to the primary visual cortex

139
Q

Give some examples of lesions of the visual pathway

A
140
Q

What’s happening in this image and what can it be caused by?

A

Lesion of OPTIC NERVE

Partial/complete loss of vision in ipsilateral eye (same side)

Caused by:

  • acute optic neuritis - Multiple Sclerosis
  • indirect traumatic optic neuropathy
  • optic atrophy
141
Q

What’s happening in this image and what can it be caused by?

A

Lesion of OPTIC CHIASM

Bitemporal hemianopia: loss if vision in temporal visual field of both eyes

Caused by:

  • tumours (pituitary adenoma, meningioma)
  • aneurysms
142
Q

What’s happening in this image and what can it be caused by?

A

Lesion of OPTIC TRACT, LGN, OPTIC RADIATION or VISUAL CORTEX

Homonymous hemianopia: loss if vision in same visual field of both eyes (can be left/right)

Caused by:

  • tumours
  • trauma
  • aneurysms (of post cerebral artery)
143
Q

Name the additional pathway that nerve fibres can project to apart from the LGN

A
  1. Superior colliculus -> eye movements
  2. Pretectal area of midbrain -> pupillary light reflex
144
Q

What’s this?

A

Goldmann perimetry test - asseses the extent of the visual field using a light stimulus

P2 Head, Neck and Neuro (11 decks)

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