neuro4 Flashcards
(63 cards)
ninety percent of retinl axons terminate where
lateral geniculate nuc
PRIMARY visual cortex corresponds to brodman area what
brodman are 17 or striate cortex
brodman areas of associated visual cortex
18 and 19
in what lobes are the higher order vision processing centers
posterior parietal and inferior temporal cortices
one eye visual field loss- where is the lesion
optic nerve on that side
bitemporal visual field defect- where is the lesion
chiasm (because it only affects the crossing fibers, which come from the nasal portion but see the outside visual field)
homonymous hemianopsia- where is the lesion
optic tract on the opposite side OR optic radiations (both parietal and temp or meyer’s loop) on the opp side
homonymous quadrantonopia-where is the lesion?
optic radiations; parietal if lower field out and temporal or meyers loop if upper field is out
homonymous hemianopia with macular sparing
occipital cortex
how to detect an afferent pupillary defect
show light in good eye and then in bad eye; if bad eye dilates instead of constricts, that is an afferent pupillary defect
where do the retinal nerves synapse?
edinger-westphal nuc in the pretectal midbrain; it in the rostral aspect of the third nerve nuc
efferent parasymp fibers from edinger-westphal nuc travel with what
cn3
efferent parasymp from the EWN travel how?
through the cavernous sinus with the inferior divison of the third nerve and synapse in the ciliary ganglion
the iris contains how many muscles that regulate pupil size
two
what innervates the pupilloconstrictor?
parasymp fibers of the third nerve
what innervates pupillodilator
cervical sympathetic system
describe the path of the symp system innervating the pupillodilator of the eye
first order neuron to pregang to postgang
where is the first order neuron in symp control of the pupillodilator?
starts in the ipsilateral posterolateral hypothalamus (first order) then porjects down the brainstem to the intermediolateral cell column at the C8-T1 spinal level.
where is the second order neuron in the symp control of the pupillodilator
cell body at c8/t1 level and neurons synapse in the superior cervical gang;
where is the third order neuron for symp control of the pupil?
start in the superior cervical gang and neurons travel along the internal carotid artery in teh cavernous sinus and from there into the orbit to teh pupillodilator muscles
horner’s syndrome
ipsilateral miosis (small pupil), ptosis (drooping of the upper lid), inverted ptosis (elevation of lower lid), and sometimes impaired ipsilateral facial flushing and sweating (anhidrosis)
cocaine test
for horners syndrome; cocaine drops will fail to dilate the abnormal pupul
how does cocaine work?
inhibits the reuptake of norepi from the synaptic cleft
apraclonidine
weak direct acting alpha 1 and alpha 2 agonist that dilates the affected eye due to denervation supersensitivity of the iris dilator muscle
