pupil

Question 1

what is the near reflex

Answer 1

constriction, accomodation, convergence

Question 2

light reflex course

Answer 2

travels with ganglion cells, bypasses lat gen and synapses on pretectal nuclei (dorsal brainstem). Internucial neuron crosses to each Edinger-westfall nucleus. EW to ciliary ganglion in orbit via CN3. Then along short ciliary fibers to targets

Question 3

reason for consensual response

Answer 3

decussation at chiasm and b/w pretectal nucleus to EW nucleus

Question 4

supranuclear effects on pupillary constriction

Answer 4

Pontine reticular formation depresses EW nucleus so depression of RF decreases pupil size (as in narcotics or pontine hemorrhage)

Question 5

mydriasis pathway (3 neurons)

Answer 5

Hypothal to ciliospinal center of budge (C8-T2). Exit at T1 to sup cerv gang via symp chain. Travels along internal carotid, thru cavernous sinus, enters orbit with V1 thru ciliary ganglion and long ciliary nerves to dilator

Question 6

Adies pupil

Answer 6

reacts minimally to light but briskly to near. Supersensitive to ACh. inflammation of ciliary gang and aberrant regeneration

Question 7

mass lesion in midbrain will affect light or near first?

Answer 7

light (more dorsal, pretectal area)

Question 8

second neuron cause of horners most likely due to

Answer 8

pancoast tumor

Question 9

Horners: cocaine administration. Hydroxyamphetamine

Answer 9

will not dilate (no release of NE to block reuptake of). Pt with 3rd neuron lesion will not dilate