Neuro: Cranial Nerves Flashcards
How many cranial nerves come from the midbrain?
2
CN 3 and 4
How many cranial nerves come from the pons?
4
CN 5, 6, 7, 8
How many cranial nerves come from the medulla?
4
CN 9, 10, 11, 12
Why are cranial nerve 1 and 2 susceptible to MS disease
They are innervated by oligodendricytes instead of schwann cells due to location (they don’t leave the CNS)
What is the only sensory nerve that reaches the cortex WITHOUT going through the thalamus
olfactory
define anosmia
loss of smell
remember much information related to taste is olfactory in origin
Where does the optic nerve cross?
The optic chiasm
Note: the optic tract is between the chiasm and the brain
if a lesion occurs on a R optial nerve, what will the visual field look like?
right eye blind
if a lesion occurs at the optic chiasm, how is the visual field impacted?
loss of lateral visual fields on both eyes
the lateral fields (temporal) cross over at chiasm
If a lesion occurs on the R optic tract, how is the visual field impacted?
loss of left visual field on both eyes
the L temporal crosses over to R side and R nasal will stay ipsilateral, forming the tract together
What nerve is responsible for pupil constriction AND orienting head and eyes (Saccadic, reflex neck movement)
Oculomotor CNIII
if your optic nerve is intact, but your oculomotor nerve is impaired, will you see pupillary constriction?
no
oculomotor causes the constriction
if your R optic nerve is impaired, and you shine light into the right eye will you see constriction? what happens if you shine it in the L eye?
R eye = neither eye constricts (cant sense the light and send to brain)
L = both eyes constrict bc L eye still able to sense and send info to brain, allowing oculomotor to constrict both
The olfactory nerve exits from what foramen?
Cribiform plate
The optic nerve exits from what foramen
Optic canal
The occulomotor nerve exits what foramen
superior orbital fissue
The trochlear nerve exits what foramen?
Superior orbital fissure
The opthamalic branch of the trigeminal nerve exits from what foramen
superior oribital fissure
The maxillary branch of the trigeminal nerve exits from what foramen
foramen rotundum
the mandibular branch of the trigeminal nerve exits from what foramen
foramen ovale
The abducens nerve exits from what foramen?
superior orbital fissure
The facial nerve exits from what foramen?
auditory canal (Stylomastiod foramen)
The vestibulocochlear nerve exits from what foramen?
auditory canal (stylomastoid)
Glossopharyngeal nerve exits what foramen?
Jugular foramen