Visual Pathway Flashcards
What supplies retina
central retinal aa
What supplies intraoribital(2) and intracranial part (2) of optic n
intraorbital- Post cillary + central retinal
Intracranial- Anterior hypophsial aa + recurrent br of opthalmic aa
What supplies optoc chiasma (2)
- Ant hypophsial aa + direct branches from int carotid
- Chiasmatic br of post communicating aa
What supplies optic tract (ant + post part)
Ant- br of post communicating aa + ant choroidal aa
post- ant choroidal aa
What supplies lat geniculate body
ant choroidal aa
thalami geniculate aa
What supplies optic radiation (2)
Deep branches of mid cerebral + post cerebral aa
What supplies visual cortex
Calacarine aa
When you are looking at something what is it projecting on to (center vision)
Macula lutea
What is the center of the macula lutea and what type of receptors does it have
Fovea centralis- Cones only (is night blind)
-(rods are more outwards)
What is the optic papilla
Slightly elevated rim of the optic disk
What is the optic disc (what exits)
Exit point for axons of ganglion cells, intraocular portion of optic n + retinal vessels
What is layer 2 of the retina
Cones (less numerous)
rods (rhodopsin is pigment)
What is in the inner nuclear layer (layer 6)
Bipolar cells- 1st order neuron of the visual pathway
Connection of bipolar cells wth fovea centralis, macular retina and peripheral retina
fovea centralis- 1 dendrite to one cone
macular retina- 1 dendrite to ~10 rods + cones
peripheral retina- 1 dendrite to approx 100 rods + cones
What is the ganglion cell layer (layer 8)
2nd order neuron of visula pathway
Special feature of ganglion cell layer
Produce melanopsin (responds to dark blue light)- therefore if rods/cones gone can still have light reflex and some sense of light
What cells help with lateral inhibition to enhance contrast of images (3)
Horizontal cells
amacrine cells
interplexiform cells
what is anatomically located ant and post to the optic chiasm
ant- ant communicating aa (can compress if aneurysm)
post- pituitary gland (tumor can compress)
What is the thrid order nueorn of the visual pathway
Lateral geniculate body
What part of the retina does baums loop project and path
Axons from signals from sup retina (lower visual field) pass thru retrolenticular part of int capsul and project above calcarine sulcus in cuneaus
What part of the retina does meyers loop project and path
Inf half of retina
-axons leave lat geniculate body and enter sublenticular part of int capsul around temporal horn of lat ventrical and project below ccalacarine sulcus into lingual gyrus
Where is a common area of compression for meyers loop
When it goes around lat ventrical
What is the cause of right sided circumferential blindness
Compression at optic nerve at optic papilla generated by retrobulbar neuritis
What is the cause of total right sided blindness
most likely due to severed optic n
What is the cause of right nasal visual field blindness
Most likely spot is compression of lat chiasm due to aneryseym of ICA
What is the cause of bilateral nasal blindness
Bilateral int carotid aa aneyreusum
What is the cause of bitemporal visual field blindness
Interuption of decussion due to tumor of pituitary gland or ant communicating aa berry aneuryssm
What is the cause of left temporal blindness and right nasal blindness
Lesion at R: optic tract, lat geniculate, optic radiation, entire primary visual cortex
What would be the cause of bilatupper left visual field defect
most likely interruption of meyes loop due to tumor of choroid plexus
(or stroke in ligual gyrus- rare)
