Visual Pathway

Question 1

What supplies retina

Answer 1

central retinal aa

Question 2

What supplies intraoribital(2) and intracranial part (2) of optic n

Answer 2

intraorbital- Post cillary + central retinal

Intracranial- Anterior hypophsial aa + recurrent br of opthalmic aa

Question 3

What supplies optoc chiasma (2)

Answer 3

• Ant hypophsial aa + direct branches from int carotid

- Chiasmatic br of post communicating aa

Question 4

What supplies optic tract (ant + post part)

Answer 4

Ant- br of post communicating aa + ant choroidal aa

post- ant choroidal aa

Question 5

What supplies lat geniculate body

Answer 5

ant choroidal aa

thalami geniculate aa

Question 6

What supplies optic radiation (2)

Answer 6

Deep branches of mid cerebral + post cerebral aa

Question 7

What supplies visual cortex

Answer 7

Calacarine aa

Question 8

When you are looking at something what is it projecting on to (center vision)

Answer 8

Macula lutea

Question 9

What is the center of the macula lutea and what type of receptors does it have

Answer 9

Fovea centralis- Cones only (is night blind)

-(rods are more outwards)

Question 10

What is the optic papilla

Answer 10

Slightly elevated rim of the optic disk

Question 11

What is the optic disc (what exits)

Answer 11

Exit point for axons of ganglion cells, intraocular portion of optic n + retinal vessels

Question 12

What is layer 2 of the retina

Answer 12

Cones (less numerous)

rods (rhodopsin is pigment)

Question 13

What is in the inner nuclear layer (layer 6)

Answer 13

Bipolar cells- 1st order neuron of the visual pathway

Question 14

Connection of bipolar cells wth fovea centralis, macular retina and peripheral retina

Answer 14

fovea centralis- 1 dendrite to one cone

macular retina- 1 dendrite to ~10 rods + cones

peripheral retina- 1 dendrite to approx 100 rods + cones

Question 15

What is the ganglion cell layer (layer 8)

Answer 15

2nd order neuron of visula pathway

Question 16

Special feature of ganglion cell layer

Answer 16

Produce melanopsin (responds to dark blue light)- therefore if rods/cones gone can still have light reflex and some sense of light

Question 17

What cells help with lateral inhibition to enhance contrast of images (3)

Answer 17

Horizontal cells
amacrine cells
interplexiform cells

Question 18

what is anatomically located ant and post to the optic chiasm

Answer 18

ant- ant communicating aa (can compress if aneurysm)

post- pituitary gland (tumor can compress)

Question 19

What is the thrid order nueorn of the visual pathway

Answer 19

Lateral geniculate body

Question 20

What part of the retina does baums loop project and path

Answer 20

Axons from signals from sup retina (lower visual field) pass thru retrolenticular part of int capsul and project above calcarine sulcus in cuneaus

Question 21

What part of the retina does meyers loop project and path

Answer 21

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

Question 22

Where is a common area of compression for meyers loop

Answer 22

When it goes around lat ventrical

Question 23

What is the cause of right sided circumferential blindness

Answer 23

Compression at optic nerve at optic papilla generated by retrobulbar neuritis

Question 24

What is the cause of total right sided blindness

Answer 24

most likely due to severed optic n

Question 25

What is the cause of right nasal visual field blindness

Answer 25

Most likely spot is compression of lat chiasm due to aneryseym of ICA

Question 26

What is the cause of bilateral nasal blindness

Answer 26

Bilateral int carotid aa aneyreusum

Question 27

What is the cause of bitemporal visual field blindness

Answer 27

Interuption of decussion due to tumor of pituitary gland or ant communicating aa berry aneuryssm

Question 28

What is the cause of left temporal blindness and right nasal blindness

Answer 28

Lesion at R: optic tract, lat geniculate, optic radiation, entire primary visual cortex

Question 29

What would be the cause of bilatupper left visual field defect

Answer 29

most likely interruption of meyes loop due to tumor of choroid plexus
(or stroke in ligual gyrus- rare)