Flashcards in Visual pathways Deck (49)
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1
What are the reflex pathways in the eye? (2)
1. pupillary light reflex
2. accommodation reflex
2
NOTE
be able to label a diagram of the eye
3
What are the 2 layers of the retina? (2)
1. non-neuronal - pigmented
2. neuronal - photoreceptors
4
NOTE - know the components of the retina
1. optic nerve
2. secondary ganglion cells
3. primary bipolar cells - link photoreceptors to G.cells
4. photo receptors
5. pigmented epithelium
6. interneuron - horizontal
7. interneuron - amacrine
5
What does the amacrine interneurone do in the retina?
modulates ganglion cells activity
6
What does a horizontal interneuron do in the retina?
modulates transmission
7
Why does light have to pass through an array of cells before it reaches the retina?
to help reduce the intensity of the light passing towards the retina
8
Where does the visual pathway run from?
retina to cortex
9
How many neurons are in the chain in the visual pathway?
3
like all the others
10
What are the primary and secondary neurons in the retina outgrowths of?
outgrowth of the diencephalon
11
What cells are in the retina in a visual pathway?
1. photoreceptor
2. bipolar cells
3. ganglion cells
12
Where do the axons of the ganglion cells run over and where to?
run over - retina
to - optic disk/blind spot
13
What does the secondary ganglion cells form?
optic nerve
14
Where does the optic nerve travel to in the visual pathway?
to lateral geniculate nucleus (LGN) in thalamus
then via optic radiation to primary visual cortex (occipital lobe)
15
What cranial nerve number is the optic nerve?
CN II
16
What is the optic nerve an outgrowth of and hence what nervous system is it a part of and what surrounds it?
diencephalon
CNS
surrounded by meninges which goes up to the eyeball
17
What is the blood supply to the eye?
central retinal artery and vein
18
What is papilloedema?
rise in CSF pressure
19
Which foramen does the optic nerve pass through?
optic canal
20
What does the optic nerve take with it and what does it form in the eyeball?
takes a layer of dura
forms the sclera
21
What is the CNS an extension of which meninges?
extension of pia mater
22
What are the symptoms of papilloedema? (4)
1. headaches
2. drowsiness
3. blurred vision
4. vomitting
23
What does the increase pressure in papilloedema compress and what does this prevent and cause?
compress - central retinal vein
prevents - venous drainage from the eye
cause - swelling of the optic disk
24
NOTE - learn the components of the visual pathway - retina to cortex (7)
1. optic nerve
2. retina
3. optic chiasma
4. lateral geniculate nucleus of the thalamus
5. optic radiation
6. primary visual cortex
7. optic tract
25
NOTE- know the cerebral topography
Lateral aspect of brain
1. visual cortex
2. visual association
Medial aspect of the brain
1. calcarine sulcus
2. visual association
26
Where does the striate cortex lie in relation to the calcimine sulcus?
1. above and below the calcarine sulcus
27
Does the nasal part of the retina send information contra laterally or ipsilaterally?
contralaterally
28
Does the temporal part of the retina send information contra laterally or ipsilaterally?
ipsilaterally
29
Where does information from the nasal part and the temporal part first get sent to?
LGN - lateral geniculate nucleus
30
