Flashcards in Lab Section 5 Deck (42):
what deficits are most helpful for localizing medulla pathology?
cranial nerve signs (because they are segmental)
which cranial nerves and nuclei are associated with the medulla?
what autonomic functions are regulated in the medulla?
respiration, blood pressure and cardiac rhythm
which cranial nerves supply the spinal nucleus of the trigeminal nerve with sensory information?
CN 5,7,9 and 10
what is the medulla called while it still contains the central canal as its lumen?
the closed medulla
portions of the ventral horn remain as what nucleus? what landmarks mark this change?
accessory nucleus CN XI
present when the pyramids are deccusating
which two structures exist throughout the brainstem and at which myelin section do they begin?
the medial longitudinal fasciculus and the reticular formation
they begin at the second section of the medulla
what does the MLF do? what does it connect?
it coordinates head and eye movements
connects the superior colliculus, the vestibular nuclei, CN nuclei III, IV and VI and the cervical spinal cord
where is the MLF most prominent?
in the more rostral areas of the brainstem where the extraocular motor nuclei lie
what does the reticular formation do around the areas of the cranial nerve nuclei?
coordinates reflexes and simple stereotyped responses mediated by the cranial nerves
what is the reticular formation generally involved with?
modulating different functions such as movement, posture, arousal, sleep, awakening, pain control and autonomic function
what are the raphe nuclei?
serotenergic neurons along the midline for the entire brainstem (involved in pain modulation)
where is the spinal nucleus of the trigeminal nerve present? which portion of the nucleus is involved with protopathic and which is related to epicritic sensation?
in both the pons and medulla
which two muscles are innervated by the accessory nerve and nucleus?
the trapezius and sternocleidomastoid
what happens to the corticospinal tract in the medulla?
first traveling as the pyramids, it crosses at the decussation of the pyramids and continues down from there
what structures involved with epicritic sensation of the body appears in the medulla? what do they look like in the external anatomy?
the gracile and cuneate nuclei (dorsal column nuclei)
bumps on the dorsal medulla are the gracile and cuneate tubercles
at which level do the gracile and cuneate fasciculi disappear? the nuclei?
gracile: fasciculus ends at the second medullary section with the nucleus in the following section
cuneate: fasciculus ends in the same section as the gracile nucleus and the nucleus at the next level
what happens to the epicritic information rostral to the dorsal column nuclei?
they cross as the internal arcuate fibers and arise as the medial lemniscus just rostral to the decussation of the pyramids
describe the somatotopy of the medial lemniscus
neck to foot somatosensory info is mapped from dorsal to ventral
when does the medial lemniscus move from its midline position?
at the junction between the medulla and the pons
what 6 cerebellar related structures are seen in the medulla?
the inferior cerebellar peduncle, the accessory cuneate nucleus, the dorsal spinocerebellar tract, the inferior olives, the vestibular nuclei and the cuneocerebellar tract
at what level can the accessory cuneate nucleus be found?
the third level up in the medulla (right when it opens up)
where can the hypoglossal nucleus be found?
dorsal to the medial lemniscus from the end of the open medulla to the most caudal section of the medulla
how does the tongue protrude if CN XII is damaged unilaterally? if the UMN is damaged (rostral to the medulla)?
cranial nerve: towards the lesion (protrusion muscle deficit)
UMN: away from the lesion (crossed circuit)
what type of neurons are in the nucleus ambiguus? where do they project mainly?
motor neurons to the larynx and pharynx projecting to CN IX and X
if the nucleus amgiguus is damaged, what are the symptoms?
hoarseness, impaired swallowing and asymmetry of the soft palate
what types of neurons are within the dorsal motor nucleus of the vagus?
preganglionic parasympathetic neurons of the vagus nerve
what does the solitary tract and its nucleus receive?
afferent info from the pharynx, larynx, cardiovascular system and gastrointestinal system (CN 7, 9 and 10)
rostral pole receives taste from the tongue
when do cranial nerve IX-XII nuclei disappear?
in the vestibular area/nuclei appear more rostrally
how many vestibular nuclei are there? what are their purpose?
mediate vestibular reflexes and to send information to the cerebellum (ICP)
what do the salivatory nuclei do? where is it located?
send axons to the ganglia of the salivary glands (CN 7 and 9)
located in the rostral medulla
where are the cochelar nuclei located?
on the external surface of the inferior cerebellar peduncle at the junction between the medulla and the pons
what are the CN VIII signs?
deafness in ipsilateral ear, nystagmus, vertigo and balance problems
what are CN IX signs?
loss of gag reflex on the ipsilateral side
what are CN X signs?
hoarseness, difficulty swallowing, assymmetry of the soft palate.
bilateral- chcoking and loss of parasympathetic control to the heart and GI tract
what are CN XI signs?
inability to elevate ipsilateral shoulder and difficulty to turn and tilt the head away from the lesion
what are CN XII signs?
paralysis of ipsilateral tongue muscles; deviation towards the side of the weakness with fasciculations and atrophy
what structures in the medulla are supplied by the anterior spinal artery? what would damage cause?
the hypoglossal nucleus, medial lemniscus and pyramids
paresis and loss of epicritic sensation of the body and tongue deviation ipsilaterally
what structures in the medulla are supplied by vertebral branches?
ALS and part of the inferior olive
what structures in the medulla are supplied by PICA?
Spinal nucleus and tract of V, inferior cerebellar peduncle, nucleus ambiguus, solitary nucleus and tract, dorsal motor nucleus of X and vestibular nuclei
what structures in the medulla are supplied by AICA?
the rostral medulla: corticospinal tract, medial lemniscus, and MLF