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pirotte Neuro
visual system
72
Other
Not Applicable
09/26/2005

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Term
where is aqueous humor made?
Definition
cilliary processes
Term
what sort of neurons project to the EWN in the pupillary light reflex?
Definition
pre-tectal
Term
where is vitreous humor?
Definition
between the lens and the retina
Term
what is the arterial supply to the eye?
Definition
opth. a. from ICA
Term
what is the arterial supply of the retina?
Definition
central retinal a.
Term
what is a diopter?
Definition
1/focal length
Term
how much of the optical power of the eye is in the cornea?
Definition
2/3
Term
what does contraction of the cilliary muscle do to the lens?
Definition
allows it to fatten
Term
how is myopia corrected?
Definition
with negative diopters
Term
how is hyeropia corrected?
Definition
with pos diopters
Term
myopia is near/far sightedness?
Definition
near
Term
what is presbyopia?
Definition
hyperopia from loss of elasticity in lens
Term
how is the lens dehydrated?
Definition
by the Na/K pump
Term
how does the cornea get energy to supply the Na/K pump
Definition
glucose from anterior chamber, o2 from the air
Term
how does the lens get E to supply the Na/K pump?
Definition
glucose from aqueous humor, anaerobic metabolism
Term
where is aqueous humor reabsorbed?
Definition
in the anterior chamber thru the spaces of Fontana
Term
where does aqu. humor go after it passes through the space of Fontana?
Definition
canal of Schlemm
Term
where does aqu. humor go after it passes through the canal of Schlemm?
Definition
ant. cilliary v.
Term
what is found in the outer layer of the retina?
Definition
pigmented epithelium
Term
what is found in the inner layer of the retina?
Definition
neural elements
Term
do photoreceptors use APs?
Definition
nyet
Term
what colors is rhodopsin sensitive to?
Definition
blue, green
Term
when are rods most useful?
Definition
low-light
Term
3 types of cones
Definition
green, red, blue
Term
more sensitive to light rods/cones?
Definition
rods
Term
general fxn of horizontal cells?
Definition
inhibit neighboring photoRs, contribute to concentric fields
Term
general fxn of bipolar cells?
Definition
input from photoR and horiz, excite amacrine and ganglion cells
Term
general fxn of amacrine cells?
Definition
input from bipolar cells, contribute to receptive fields of ganglion cells
Term
what cells activate ganglion cells?
Definition
bipolar, amacrine
Term
fxn of ganglion cells?
Definition
transmission along optic nerve
Term
3 types of ganglion cells
Definition
Y, X, W
Term
large ganglion cells?
Definition
Y
Term
small ganglion cells?
Definition
X
Term
what stimulus do W-cells respond to?
Definition
light intensity
Term
to where do W-cells project?
Definition
sup coll, pretectal region
Term
what are Mueller cells?
Definition
similar to astros, regulation of ionic/NT environ of retina
Term
what happens when retinal is struck by a photon?
Definition
11-cis --> all trans
Term
all-trans retinal acts like a...
Definition
G protein R
Term
retinal activates...
Definition
transducin
Term
transducin activates...
Definition
cGMP phosphodiesterase
Term
what effect does dec. cGMP concentration have in phototransduction?
Definition
cGMP dissociates from Na/Ca channels, closing them
Term
what is dark current?
Definition
in/out Na movement in the photoreceptor
Term
what is the effect of the closing of the Ca channel in phototransduction?
Definition
decreased Glu release
Term
glutamate is inhibitory to hor/bip cells in...
Definition
on-centers
Term
glu is excitatory to hor/bip cells in...
Definition
off-centers
Term
are Y cells good at color discrim?
Definition
no
Term
what are Y cells not good at color discrim?
Definition
recieve input from all 3
Term
Y cells: large/small fields?
Definition
large
Term
projection of Y cells?
Definition
magnocellular in LG
Term
what are Y cells sensitive to?
Definition
movement
Term
how many types of cones are X cells sensitive to?
Definition
one
Term
discuss X cells as they related to on-center fields
Definition
ex/inhib reversed with two colors
Term
X cells: small/large fields?
Definition
small
Term
to where to X cells project?
Definition
parvocellular LG
Term
what surrounds the optic nerves?
Definition
pia, arach, dura
Term
what part of the retina decussates at the chiasm?
Definition
nasal (temporal field)
Term
what part of the retina remains uncrossed at the chiasm?
Definition
temporal (nasal field)
Term
why do some optic fibers project to the suprachiasmatic n?
Definition
ciracdian rythym
Term
how are fibers in the optic tract oriented?
Definition
similar visual fields are close to each other
Term
in which tract is the right visual field?
Definition
left
Term
which layers in the LG recieve ipsilat input?
Definition
235
Term
which layers in the LG recieve contralat input?
Definition
146
Term
what part of the LG is the parvocellular region?
Definition
four outer laminae
Term
what part of the LG is the magnocellular region?
Definition
2 inner laminae
Term
which part of the LG is involved in depth and contrast?
Definition
magno (y)
Term
how does the lower visual field get from the LG to 17?
Definition
courses over the lateral vent
Term
how does the upper visual field get from the LG to 17?
Definition
around inferior horn of lat vent
Term
upper visual field on bottom/top of CalcSulc?
Definition
bottom
Term
where is the left visual field in the cortex?
Definition
right 17
Term
macula terminates on post/ant occipital lobe?
Definition
post
Term
what is the fxn of the "dorsal stream" of visual processing?
Definition
"where"
Term
what is the fxn of the "ventral stream" of visual processing?
Definition
"what"
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