CN 1&2 Flashcards
cn 1 and 2 are extensions?
of the forebrain
T or F…. cn 1 and 2 do not have nuclei?
true
alar plates become? formed from?
ectoderm > roof > alar plate > posterior horn > sensory/afferent
basal plate becomes? formed from?
notochord > floor plate > basal plate > anterior horn > motor/efferent
motor or sensory is medial or lateral?
mEdial = Efferent/motor (basal) lAteral = Afferent/sensory (Alar)
zone of autonomic neurons becomes the?
lateral horn
what ventricle causes separation of posterior paltes?
4th ventricle
why is repiratory epithelium unique when compared to olfactory?
respiratory cilia MOVES to ceates waves to allow mucus to move and olfactory does not
what are the 4 cell types of olfactory epithelium?
1) olfactory cells
2) bowman’s glands
3) support cells
4) basal cells
1) olfactory cells does what?
2) bowman’s glands
3) support cells
4) basal cells
1) 1st order nueron, located IN olfactory epithelium
2) secertory glands, push material to surface and prodcuce mucus to capture odors to start impulse at 1st nueron
3) keep ionic gradients the same so you do not fire a signal when you don’t want to
4) some regeneration
what makes olfactory cells unique?
they can regenerate
do you see olfactory nerves in disections?
no. cribiform plate on ethmoid bone has olfactory neurons passing through it, so in disections they are lost
* *we see 2nd NEURONS in the olfactory bulbs
only 10% of what you smell is what you breath, so how do you smell?
1) RETRONASALLY from back of mouth
2) up to nasopharynx
3) thru coana
4) to nasal cavity
5) excite 1st order olfactory nerves emedded in epithelium
- –peripheral extensions out to cilia and central extensions up thru cribiform plate to synapse on
6) 2nd order neuron called MITRAL CELLS in olfactory bulb
7) 2nd travels thre MEDIAL and LATERAL STRIA to synpase directly on primary olfactory cortex
* *does NOT pass thru thalamus unless going thru limbic system for higher order stuff
when does olfactory info pass thru thalames?
ONLY when participating in limbic system for higher order info like memory or emotion
what are the 2nd order neurons of olfaction called?
mitral cells
what cell is the 1st order neuron for olfaction?
olfactory cells
explain the steps for taste
1) comes in thru glossopharengeal, vegus, and facial n
2) goes ipsilaterally to the solitary nucleus, which is important for any knid of visceral scent (wet sense= olf. and taste)
3) direct connections to reflexes, like gag
- -also the solitary tract which connects to upper tract (aka central tegmental tract) which will go up to the thalamus and insula
the terminal part for taste and olfaction is the SAME. where?
INSULA
**tracts on how they get there is different
solitary nucleus (olfaction and taste)
visceral reflexes
–direct synapses with efferent nuclei
solitary tract (olfaction and taste)
input from visceral afferent
– merge to form central tegemental tract which will reach the limbic nuclei and insula
what are the retinal cell layers?
where are they found??
1) photoreceptors
2) bipolar cells
3) ganglion cells
* *the first 3 neurons of optic pathway are ALL within the retina!
vitreous cvity
clear gel the fills the space between the lens and the retina of the eyeball
blind spot
where all the axons of 3rd order optic cells merge on retina
what layers of dura does CN2 have aroudn it?
all 3 layers! (pia, aracnoid and dure)
**bc it is an extension of the CNS
retina is divided into ___ and ____ havles
nasal and temporal
what vessel supplies ALL of the retina?
central artery of retina
*if damaged you are blind
axons from the ____ half of each retina decussate at the _____
nasal half
decussate at optic chiasm
joined fibers at the optic chiasm continue as _______, most terminating on ___ order neruons in the lateral geniculate bodies
optic tracts
**4th order
What and where is LGN?
in the thalamus and is cell bodies of the 4th order neurons of optic pathway
visual fields =
hemifields
axons from the 4th order neurons in the LGN fan out as optic radiations, terminating in the?
primary visual cortex of the occipital lobe (90%)
10% of optic fibers do NOT terminate at the?
LGN
if optic fibers do not terminate at the LGN, then what happens to them
they go back to the coliculi to synapse on efferents
**this is how we get reflexes (not really knowing or seeing before we respond)
what sulcus separates the lower and upper halves of the primary visual cortex? name them
calcarine sulcus
- cuneus on top
- lingual on bottom
L visual hemifiled is going to end up on the?
R visual tract
R geniculate nucleus
R optic radiations
R visual cortex
the top visual feild (aka what you see) will be interpreted by the?
lingual gyrus on the bottom
what is meyers loop?
inferior most radiations diving deep into terminal lobe to lingual gyrus
what is the uncus? location of what cortex?
cleft in the temporal lobe where primary olfactory cortex is located
most seizures occur in what lobe?
temporal
halo test
drop of blood on papaer and if a shadow around outside occurs then there has been damage to cribiform plate
* tests for CSF rhinorrhea
sella turcica houses?
what happens if there is a tumor of this?
pituitary gland
- first symptom is loss of vision
- causes compression of optic chiasm
- bitemporal hemianopia
