Chapter 5: The Brain Stem Flashcards
Label the figure.
Brain Inferior View
Which cranial nerves arise from the midbrain?
CN III and IV
oculomotor and trochlear
Which cranial nerves enter or exit from the pons?
CN V, VI, VII, and VIII (trigeminal, abducens, facial, and vestibulocochlear)
Which nerves enter and exit from the medulla?
CN IX, X, and XII (glossopharyngeal, vagus, and hypoglossal nerves)
Where are motor nuclei located in the brainstem in general?
more medially
Where are sensory nuclei located in the brainstem in general?
more laterally
Which CN in the brainstem are purely motor?
CN III, IV, VI, XII
( oculomotor, trochlear, abducens, hypoglossal)
Which CN in the brainstem have a sensory component?
Which ones are mixed?
laterally located ones CN V, VII, IX, X
trigeminal, facial, glossopharyngeal, vagus respectively
Does CN IV exit from the dorsal or ventral part of the brainstem?
dorsal
Is CN VII sensory or motor?
mixed
Label the image and distinguish which section of the brainstem it is from.
Upper midbrain level of nerve III
Label the image and distinguish which section of the brainstem it is from?
lower midbrain: level of nucleus CN IV
Label the image and distinguish which section of the brainstem it is from?
Middle pons level of nerve V
Label the image and distinguish which part of the brainstem it is from.
Lower pons; level of nerves VI and VII
Label the image and distinguish which part of the brainstem it is from?
open medulla
Label the image and determine which part of the midbrain it is from.
closed medulla; lower medulla
CN I name.
olfactory nerve
CN I type.
sensory
CN I function.
smells
Result of CN I lesion.
anosmia
CN II name.
optic
CN II type.
sensory
CN II function.
sees
Result of a CN II lesion.
- visual field deficits (anopsia)
- loss of light reflex with III
- only nerve to be affected by MS
CN III name.
oculomotor
CN III type.
motor
CN III function.
- innervates SR. IR, MR, IO extraoculuar muscles: adduction (MR) most important action
- raises eyelid (levator palpebrae superioris)
- constricts pupil (sphincter pupillae)
- accommodates (ciliary muscle)
What are characteristics of lesions of the oculomotor nerve?
- diplopia, external strabismus
- loss of parallel gaze
- ptosis
- dilated pupil, loss of light reflex with II
- loss of near response
CN IV name.
trochlear
CN IV type.
motor
CN IV function
superior oblique- depresses and abducts eyeball (makes eyeball look down and out)
intorts
Lesion of CN IV?
- weakness looking down with adducted eye
- trouble going down stairs
- head tilts away from lesioned side
CN V name?
trigeminal nerve