Opt 114 visual pathway: optic chiasm, optic tract

where is the optic chiasm found

anterior to the pituitary gland

is the optic chiasm always found in exactly the same place

no

the optic chiasm is anteriorly displaced in what percentage of the population

10%

the optic chiasm is posteriorly displaced in what percentage of the population

15%

what surrounds the optic chiasm

circle of willis

which fibers cross at the chiasm

nasal fibers from each eye

what happens to the nasal fibers after they cross at the chiasm

continue posteriorly in the contralateral optic tract

do all nasal fibers of the optic chiasm cross directly

no

what is the anterior knee of wilbrand

inferior nasal fibers loop anteriorly into the contralateral optic tract

what is the posterior knee of wilbrand

superior nasal fibers loop posteriorly in the ipsilateral optic tract before crossing

which fibers remain uncrossed in the optic chiasm

temporal ganglion nerve fibers

what do the temporal fibers do after the optic chiasm

continue posteriorly in the ipsilateral optic tract

inferior nasal fibers are involved in what at the optic chiasm

anterior knee of wilbrand

superior nasal fibers are involved in what at the optic chiasm

posterior knee of wilbrand

what are the optic tracts made up of

ipsilateral temporal and contralateral nasal ganglion nerve fibers

are the optic tracts divided further than left and right?

yes

what are the divisions of the optic tracts

small medial, large lateral roots

what percentage of fibers make up the small medial root of the optic tract

10%

what percentage of fibers make up the large lateral root of the optic tract

90%

how many places does the small medial root synapse in

4

what 4 places does the small medial root synapse in

-superior colliculus

-pretectal nucleus

-parvocellular reticular formation

-hypothalamus

what does the superior colliculus do

eye/head movement coordination

what does the pretectal nucleus do

pupillary light reflex

what does the parvocellular reticular formation do

control arousal

what does the hypothalamus do

control circadian rhythms

where does the large lateral root synapse

lateral geniculate nucleus

where is the lateral geniculate nucleus

thalamus

what is the thalamus

relay station for sensory/motor information

what fibers does the lateral geniculate nucleus receive

ipsilateral temporal and contralateral nasal fibers

axons of neurons of the lateral geniculate nucleus form what

optic radiations