Lab 2 Cranial Nerves Flashcards
What 3 structures make up the brainstem?
- midbrain
- pons
- medulla
What is the tectum of the midbrain?
the region dorsal to the cerebral aqueduct
What is the base of the brain stem?
the ventral aspect of brainstem
What is the tegmuntum?
the brainstem region dorsal to the base and ventral to the cerebral aqueduct/4th ventricle [exists in midbrain/pons/medulla]
What is the function of the substantia nigra in the midbrain?
- part of basal ganglia motor control system
What is the function of cerebral peduncles in the midbrain
contains descending projections from cerebral cortex to brain and spinal cord
What is the function of the red nucleus in the midbrain?
part of cerebellar motor control system
What is the cerebral aqueduct in the midbrain?
part of ventricular system between 3rd and 4th ventricles
What is the function of the periaqueductal grey in the midbrain?
pain perception and control and reflexes for orienting to the source of sensory stimuli
What is the function of the superior collilculus in the midbrain?
sesnory-motor integration
What is the function of the inferior colliculus in the midbrain?
auditory processing
Which 3 nerves emerge from the midbrain?
- oculomotor [CN III]
- trochlear [CN IV]
- tract of CN V
What part of the brainstem contains the caudal part of the 4th ventricle?
the medulla, rest is in pons
What is the function of superior cerebellar peduncles?
contain efferent axons from cerebellum to the red nucleus and thalamus
part of motor control system
What is the function of middle cerebella peduncles?
contain crossed projects from pontine nuclei to cerebellum
What is the function of pontine nuclei?
relay between cerebral cortex and cerebellum
What is the locus coeruleus?
nucleus that is principle site for brain NE production?
What is the principle site of NE production in the brain?
locus coeruleus
What structures are in the midbrain tectum?
XX
What is the function of the two areas of the reticular formation? where are each located?
caudal portion: located in medulla and lower pons, involved in motor and autonomic function
rostral: in upper pons and midbrain, important for eye movement control and regulating level of consciousness
What is the inferior olivary nucleus/complex?
part of cerebellar motor controll system
projects to opposite cerebellum via inferior cerebellar peduncle
What is function of the medullary pyramids?
contain descending corticospinal axons/tracts
Where does CSF drain from 4th ventricle into subarachnoid space?
- at lateral angles of the pontomedullary junction
What is importance of inferior cerebellar peduncle
- integrates proprioceptive sensory input with motor vestibular
- important for balance and posture maintenance
What is the raphe nuclei of the medulla?
group of nuclei that release serotonin
What is the medial lemniscus?
- crossed fibers that carry somatosensory info through medulla, pons and midbrain to the thalamus
- arises from dorsal columbs/gracile and cuneate nuclei and fasiculi
What is important about the pyramidal decussation?
marks the boundary of medulla and spinal cord
What is the obex?
point at which 4th ventricle narrows to become central canal of spinal cord
What is locked in syndrome?
- pt aware and awake but cannot move or communicate due to complete paralysis of voluntary muscles in body
- exception = can move eyes
- result of brainstem lesion at level of pons
What causes locked in syndrome?
- damage to brainstem at level of pons
- could be due to stroke or blockage at level of basilar artery [which gives rise to pontine arteries]
What is the blood supply to the pons?
pontine arteries that come off of the basilar artery
Why can cerebellar or tonsillar herniation be so deadly?
- causes compression of the lower brainstem
- increased pressure on brainstem leads to dysfunction in brain centers responsible for respiratory control and cardiac function
Are motor or sensory cranial nerve nuclei located more medially in the brainstem?
MOTOR = MEDIAL
What 3 cranial nerve nuclei/nerves/tracts have GSA?
- trigeminal mesencephalic nucleus + tract
- trigeminal prinicpal censory nerve
- trigeminal spinal tract and nucleus
what 1 sensory cranial nucleus has GVA/SVA?
solitary nucleus
What 2 sensory cranial nerve nuclei have SSA fibers?
- vestibular nuclei
- cochlear nuclei
What 4 motor cranial nerve nuclei have GSE fibers?
- oculomotor nucleus
- trochlear nerve nucleus
- abducens nerve nucleus
- hypoglossal nerve nucleus
What 3 motor cranial nerve nuclei have GVE fibers?
- Edinger-Westphal nucleus [III]
- dorsal motor vagal nucleus
- nucleus ambiguus
What 4 cranial nerve nuclei have SVE fibers?
- trigeminal motor nucleus
- facial nucleus
- nucleus ambiguous
- spinal accessor nucleus [of XI]
Where does CN1 exit the brainstem?
- does not emerge from brainstem
- emerges directly from forebrain
Where does CN2 exit from brainstem?
- does not emerge from brainstem
- emerges directly from forebrain
Where does CN3 exit from brainstem?
- ventrally
- from interpeduncular fossa of midbrain
What is the gracile tract?
- medial portion of dorsal column
- sensory fibers from lower body
What is the cuneate tract?
- lateral portion of dorsal column
- sensory fibers from upper body
What does funiculus mean?
spinal cord white matter zone usually with more than one tract
difference in function ventral vs dorsal horn?
- both grey matter
- dorsal = sensory
- ventral = motor
What is intermediolateral cell column? where is it present?
- lateral side of grey matter horn
- present in thoracic and lumbar
- sympathetic preganglionic cell bodies
What is clarke’s nucleus? where is it located?
- in medial part of intermediate gray matter
- present C8-L3
- part of cerebellar motor control system
- conveys limb position info to cerebellum
cervical enlargement?
C5-T1
lumbar enlargement?
L2-S2
