anat and physiology of vision 2 Flashcards Preview

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Flashcards in anat and physiology of vision 2 Deck (20):
1

what are 2 visual fields and what do they project onto

nasal - onto temporal retina
temporal - onto nasal retina

2

how is image that is projected oriented

upside down and laterally inverted

3

where does retinal processing occur

middle 3 layers of the retina

4

what does retinal processing do

drown out much of the excess light noise

5

3 reasons visual acuity is high in fovea

1. anatomical structre
2. types of photo receptors
3. ratio of ganglion cells to receptors

6

what is anatomically significant about fovea (3)

1. avascular
2. only photoreceptors and a few glia -not 8 layers on top
3. ganglion cells divert around fovea

7

where are most rods and cones

cones - in fovea
rods - around the fovea

8

average ratio of ganglia to receptor in retina andfovea

retina 370:1
fovea 1:1
periphery 1000:1

9

what is function of retinal pigmented epithelium

provides metabolic and ionic conditions neccesary for rods and cones

10

what happens to RPE with age

age related macular degen - get debris (drusen) that collects in macula and causes vision problems

11

3 types of macular disease

1. wet ARMD - get blood into spaces
2. dry ARMD - drusen accumulation
3. subretinal fibrosis - end stage macular degen

12

5 potential causes of optic nerve pathology

1. glaucoma
2. optic neutitis
3. ischemia
4. inflammation
5. compression

13

3 areas of brain where signals from retina are sent

1. suprachiasmatic nucleus of hypothalamus - bio clock
2. lateral geniculat of thalamus - relays to visual cortex
3. pretectal region of midbrain - pupillary light reflex

14

where are projections

review color slides

15

how does field loss project

upside down and backwards to the site of visual pathway lesion

16

what does loss respecting horizontal midline of visual suggest

retina/optic nerve lesion

17

what does loss respecting vertical midline of visual suggest

optic chiasm or retro chisamic

18

4 possible causes of chiasmal defects

1. pit. adenoma
2. suprasellar meningioma
3. craniopharyngioma
4. aneurysm of ICA

19

which hemisphere does right visual field project to?

left

20

how much does fovea get represented in cortex

1%, but gets half

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