pupillary light reflex

[ctizzle13498]

With pupillary light reflex: lets say you shine light in the left eye. So the info travels down the left optic nerve, but at the chiasm, does it split and some goes to the right optic tract and some to the left optic tract, or does it continue in the left optic tract until it reaches the pretectal nucleus and then splits when it goes to the EW nucleus? First Aid's drawing is a little weird.

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[ctizzle13498]

Also, could someone explain vestibular appartatus. The whole COWS thing. So this is what I'm thinking:

If you put cold water is a person's right ear: you will get nystagmus toward the right with quick phase towards left? Or is that backwards? How do you know what side the lesion is?

 

[lemonade90]

For your first question, light hits the eye, goes down the optic tract. The CN II fibers split around the optic tract. Fibers in the ipsilateral optic tract go to the ipsilateral pretectal nucleus. Fibers which crossed over go to the contralateral pretectal nucleus. The pretectal nucleus on either side synapses with BOTH Edinger Westphal nuclei. These then send CN III fibers to the eyes to complete the arc.

 

[jfgavina]

thanks lemonade, FA does a poor job explaining this I figured out by myself that it could be like that but I wasn't sure

 

[ctizzle13498]

OMG! neuro DIT lectures TAKE FOREVER!

 

[jfgavina]

It only left me with time for one UW block those lessons and sometimes I couldn't to all 3 lessons LOL with pauses and rewinds...

are you doing DIT by the second time ctizzle?

 

[ctizzle13498]

nah...i did it in a different order: like neuro was always my strongest, so i saved it for the end....ill be officially done DIT this week: i have 2 musculo lectures and 1 more neuro. then i take NBME 12 and see how much I improved and then 1 solid month to MEMORIZE MEMORIZE MEMORIZE

 

[jfgavina]

you will see improvements 4 sure. don't put yourself too away from doing questions... I feel like I should be doing questions everyday and I only stoped it 1 week ago. and will be only 2 weeks and a half w/o doing questions (not counting nbmes of course). questions make you think.


also, I decided not to read all RR path goljan blue margins, will go only thru the images but defenitely will do the goljan biochemistry HYields. I'm finding my uw notes extremely helpul so maybe will read it 2 times. finished FA again today

ok my plan for these last 12 days:

-reading uw notes one or 2 times (about 170 pages)
-read DIT notes 1 time (140 pages)
-read FA again
-review RR images
- read biochemistry goljan HY
-1 or 2 nbme


lets see if I have time for this all, and don't forget to report score! GL

 

[ctizzle13498]

Thanks! Good luck to you too! Will keep you posted on sunday!