4.2 vision Flashcards
anterior segment of the eye 5
cornea
iris
lens
ciliary body
anterior and posterior chamber
posterior segment of the eye
vitreous humour
retina
optic nerve
3 layers of the eye
fibrous tunic
vascular tunic
nervous tunic
vertical retinal circuitry 3
photoreceptors
bipolar cells
ganglion cells
horizontal retinal circuitry 2
horizontal cells
amacrine cells
what do amacrine cells do
inhibitory cells between bipolar and ganglion layers
what do horizontal cells do
inhibitory cells between photoreceptor and bipolar cells
what is a the two key characteristics about the visual field representation
image on the retina is inverted and reversed
visual neuropathway up to three terminations 6
optic nerve
optic disc
optic foramen
optic chiasm
medial fibres cross, lateral do not
optic tract terminates at three regions; LGN of thalamus, superior coliculus, prtectal area
where does the optic tract first terminate 3
LGN of the nucleus
superior colliculus
pretectal area
from the lateral geniculate nucleus where does visual pathway go
optic radiations: of which there are two superior and inferior. Superior goes to cunues and inferior goes to lingula of primary visual cortex
what is the extrageniculate pathway
this is the visual pathway which extends from the pretectal and superior colliculus area
what is the superior colliculus function in vision
orientating the eyes to a new stimulus
what is the pretectal area important for in vision
pupillary light reflex and accomodation light reflex
dorsal stream in visual
is your where stream, goes to the parieto-occipital association cortex
responsible for spatial relatinoships
ventral stream
your what stream, goes to your occipito-temporal association cortex responsible for features
what are the three key things you look for via an opthalmoscope
optic disc
macula
fovea
where is the highest density of cones
fovea
macula 3
- region in cntr of retina
- critical for central vision
- yellowish hue
rods in terms of sensitivity and acquity 2
high sensitivity
low acquity
cones in terms of sensitivity and acquitity
low sensitivity
high acquity
homonymou hemaniopia
is when the same side of the eye is affected. In one eye this will effect the nasal and in the other the temporal field but they are both on the same side.
ex. right homonymous hemaniopia will result in left nasal lost and right temporal lost
when do you get homonymous hemaniopia
lesion of the optic tract or optic radiations
