The Eye Flashcards
What do photoreceptors convert light energy into
neural activity
what is the pupil
the opening where light enters the eye
what is the optic nerve
bundle of axons from the retina
what is myopia
near-sightedness
what is hyperopia
far-sightedness
what is visual acuity
ability to distinguish between two points
what is the visual field
amount of space viewed by retina when the eye is fixated straight ahead
what is the visual angle
distance across the retina described in degrees
microscopic anatomy of the retina?
photoreceptors to bipolar cells to ganglion cells
retinal processing is also influenced by _________
lateral connections
which cells laterally connect photoreceptors and bipolar cells?
horizontal cells
which cells laterally connect bipolar and ganglion cells?
amacrine cells
what are the regions of the photoreceptors?
outer segment, inner segment, cell body, synaptic terminal
what are the two types of photoreceptors?
rods and cones
which photoreceptor has more disks
rods
which photoreceptor is LESS sensitive to light
cones
what is duplex retina
having both rods and cones
what is the relative structure peripheral retina?
more rods than cones + more photoreceptors than ganglion cells
at what point is visual acuity maximized?
fovea
which photoreceptors are in central fovea?
cones only
Light energy interacts with photopigment to produce a change in ________
membrane potential
GPCR causes a change in _______
second messenger
rod outer segments are depolarized in the dark because of
steady influx of Na+
Why does the sodium channel close in response to light?
the cGMP that gates it is converted to GMP by phosphodiesterase
How is phosphodiesterase activated in response to light?
Rhodopsin activates transducin which activates phosphodiesterase
which opsin has the longest wavelength? (560)
Red
what is the receptive field?
the area of retina where light changes neuron’s firing rate
phototransduction parallels _________
olfactory transduction: electrical to chemical to electrical signal
is the mapping of visual space onto retina cells uniform?
No, there are 97 mill photoreceptors to 1 mill RGCs
What theory explains our perception of color?
Young-Hemholtz trichromacy theory of color vision
Where is the cell body of the ipRGC located?
in the ganglion cell layer of the retina instead of the outer nuclear layer with the rods and cones
What is the communication difference b/w ipRGCs vs rods and cones
don’t need bipolar cells to communicate? unclear
