Visual System Flashcards
uvea
the apparatus of ciliary body and iris
retinal pigment epithelium fxn? layer?
instrumental in the health of the retina. without it the retina dies (i.e. retinal detachment)
layer 1
optic disk
where gangion cell axons collect to form the optic nerve; blind spot
macula lutea
- contains the FOVEA,
- most ACUTE vision.
- it is YELLOW
where does the optic nerve come from
developmentally the optic cup comes from the diencephalon
review: where does the lens come from?
the ectoderm.
whats layer 2
Rods and cones
rods and cones project to?
horizontal and bipolar cell
what do horizontal cells connect to
- other rods/cones.
what do bipolar cells connect to
rods/ cones ==> amacrine cell and gangion cell
amacrine cells connect to
bipolar cells and ganglion cells
where are the nuclei of rods and cones
in the outer nuclear layer (layer 4)
where do the synapses between bipolar cell and rods/cones
outer plexiform layer (layer 5)
where are bipolar cell bodies
inner nuclear layer (layer 6)
where bipolar cells synapse with ganglion cell
inner plexiform layer (layer 7)
where the banblion cell body is
ganglion cell layer (layer 8)
optic disk is ALWAYS ___ to fovea
medial
are there retinal layers in fovea?
not really. there are only cones here, and the cones have a 1:1 relationship with bipolar cells…. the info basically goes directly to the photoreceptor layer of the eye. theres a lot LESS convergence
scotopic vision is
low light vision
photopic vision is
best acuity becuase the cones are taking over, and rod saturation is present
what portion of the retinal information goes over to the right lateral geniculate nucleus
right lateral geniculate nucleus gets info from the temporal half of the R retina AND the nasal portion of the L retina
optic tract gets blood from?
lesion is called?
anterior choroidal artery. lesion is homonymous defect
4 arteries of optic radiations
PCA deep branches, anterior choroidal, MCA inferior division, PCA
first two layers of lateral geniculate nucleus
magnocellular layrs, receive input from retinal ganglion from M cells; LARGE receptive fields that are FAST conducting, info relating to MOTION
last four layers of lateral geniculate layers
parvocellular layers get input from retinal ganglion p cells and have SMALL receptive fields and COLOR info (cones)
what layers of lateral geniculate layers are for CONTRALATERAL eye
contralateral=1,4,6
each point in visual space is mapped….
6 times in the LGN
line of gennari
axons that form a line in layer 4 of the cortex… primarily in layer 4C
THIS IS ONLY IN BRODMAN AREA 17
layer 4C alpha gets info from
M cells (magnocellular)
layer 4C beta gets info from
P cells (parvocellular) Crunchy Peanut Butter ==>4Cbeta=Pcells
striate cortex
the special name for the primary visual cortex
akinetopsia
a lesion to the WHERE stream; its the inferior temporal part; related to color and form. problem recognizing faces, color
which brodman areas have V3, V4, V5
18 and 19
functional columns of the striate cortex
they all respond to a BAR of light with the same angle. this is called orientation columns; they are also organized by blobs and ocular dominance columns (R vs L)
scotoma
little blind SPOTS that you can get from diabetes. you probably won’t even know that you have them unless you get a visual field test done
monocular visual loss
total transection of the optic nerve; total loss of the visual field in one eye
bitemporal hemianopia
loss of the nasal portions of bilateral retinas; you lose the temporal visual field in both eyes; this is a lesion of the optic chiasm
contralateral homonymous hemianopia
loss of the same half of the visual field in each eye; loss of optic tract or a total transection of the optic radiation
contralateral superior quadrantopia
lesion of meyer’s loop; loss of upper quarter of visual field in both eyes (same side in both eyes); pie in the sky
contralateral inferior quadrantopia
pie on the floor; loss of superior portion of the optic radiation; loss of lower quarter of visual field in both eyes, (same side in both eyes)
prosopagnosia
inability to recognize FACES; especially a lesion to the right side; inferior occipital gyrus, middle fusiform gyrus; PCA
capgras syndrome
don’t have the EMOTIONALtie to the visual tie; problem connecting to the AMYGDALA; it looks like your parent, it looks like someone you know, but you deny that its your parent because you just don’t have that connection
achromaatopsia
damage to area V4 (area 19) partial or complete loss of color vision. the WHAT stream
left hemineglect lesion
right parietal region
balint syndrome
usually a lesion to the left PARIETAL lobe; optic ataxia ; gaze apraxia ; simultanagnosia
simultagnosia
problem paying attention to MULTIPLE things in their visual field
gaze apraxia
deficit in directing gaze
number- color synestheesia
when they see a NUMBER, its a COLOR; lesion with the FUSIFORM area of the left brain
blind sight syndrome
new pathway is damaged, but the old pathway is intact so they can orient objects and track with eyes and head. they have a “sixth sense”
