Visual Pathways

Question 1

what are the sensory nerves for the orbit?

Answer 1

optic nerve (CN II)
trigeminal nerve (CN V1)

Question 2

what are the motor nerves for the orbit?

Answer 2

oculomotor (CN III)
trochlear (CN IV)
abducens (CN VI)

Question 3

what is a blow out fracture?

Answer 3

a blow to the front of the face that causes the medial bones of the orbit to fracture due to how fragile they are

Question 4

what are the three layers of the globe?

Answer 4

fibrous tunic
vascular tunic
neural tunic

Question 5

what does the neural tunic contain?

Answer 5

retina

Question 6

what are the layers of the retina and what is their function?

Answer 6

retinal pigment epithelium- absorbs scattered light

neural retina- contains photo receptors and a fovea

Question 7

what is the fovea?

Answer 7

area of the retina with the highest concentration of cone photoreceptors and the area of sharpest vision

Question 8

what is the path of light in the layers of the retina?

Answer 8

nerve fiber layer
ganglion cell layer
inner plexiform layer
inner nuclear layer
outer plexiform layer
outer nuclear layer
inner and outer segments of rods/cones
retinal pigment epithelium

Question 9

where the most cones found?

Answer 9

near the fovea

Question 10

where is the optic chiasm located?

Answer 10

superior to sella turcica

Question 11

what would happen if there was a macro-adenoma in the sella turcica?

Answer 11

your peripheral vision that strikes the nasal hemi retina is cut off causing bitemporal hemianopsia

Question 12

the central targets for the retinal ganglionic cells includes?

Answer 12

• hypothalamus, pretectum, superior colliculus
• lateral geniculate nucleus of the thalamus

Question 13

where does the lateral geniculate nucleus mainly project?

Answer 13

primary visual cortex (area 17) or area V1 (not CN V1)

Question 14

the optic radiations from the lateral geniculate nucleus can be divided into what two fiber groups?

Answer 14

retrolenticular fibers
sublenticular fibers also called meyer’s loop

Question 15

what are the two gyri of the primary visual cortex and what are they separated by?

Answer 15

cuneate gyrus
lingual gyrus
calcarine sulcus

Question 16

central projections to the lateral geniculate nucleus from a LOWER visual field will travel to what gyrus?

Answer 16

cuneus through the retrolenticular fibers

Question 17

central projections to the lateral geniculate nucleus from a UPPER visual field will travel to what gyrus?

Answer 17

lingula through the sublenticular fibers/meyer’s loop

Question 18

what is the unimodal association cortex?

Answer 18

deals with information from one sense modality (vision)

Question 19

what is the heteromodal association cortex?

Answer 19

manages information from multiple sense modalities (auditory and visual or somatosensation)

Question 20

where else can retinal ganglion cells have axons project other than the LGN?

Answer 20

pretectal region of the midbrain which controls pupillary light reflex

Question 21

what is the edinger-westphal nucleus?

Answer 21

a nucleus in the oculomotor nuclear complex parasympathetic innervation to lens and pupillary dilators