4 - The Visual Pathway Flashcards
10 layers of the retina:
RPE Photoreceptors External Limiting Membrane Outer Nuclear Outer Plexiform Inner Nuclear Inner Plexiform Ganglion Cell Nerve Fiber Layer Inner Limiting Membrane
the visual pathway begins in the photoreceptors, followed by 3 neuron chain:
bipolar - ganglion - neurons in LGN of thalamus
photoreceptors release glutamate to bipolar cells in _
the dark (inhibitory)
OFF bipolar cells are _ receptors
less glutamate (light) = _ cation conductance
cell _
ionotropic
less
hyperpolarizes (does not fire)
ON bipolar cells are _ receptors
less glutamate (light) = _cation conductance
cell _
metabotropic
more
depolarizes (AP fired)
ON and OFF cells are always working to detect changes in light levels
increased light - _ depolarizes
decreased light - _ depolarizes
ON
OFF
ON bipolar cell synapses with _ ganglion cell;
ON ganglion cell _ when signal comes from center as opposed to surround
ON
fires more rapidly
3 ganglion cell types:
midget, parasol, bistratified
Midget ganglion cells make up the majority of the cells that project to the _
origin of the _ pathway
LGN
parvocellular
parasol ganglion cells make up _% of cells that project to LGN
origin of the _ pathway
10
magnocellular
bistratified ganglion cells make up _% of cells that project to LGN
origin of _ pathway
8
koniocellular
midget cells (parvo) detect _ parasol cells (magno) detect _ bistratified (konio) detect _
color (R/G), detail
motion, contrast, shape
blue and yellow
projection of visual fields on each retina are _ and _
inverted and perverted
at LGN, visual field information is _
lateralized
some fibers _ LGN
bypass
