Medulla Flashcards
Pyramidal decussate on
Roughly 80-90% of corticospinal tract fibers cross, these fibers descend in the lateral funiculus, some fibers descend ipsilaterally via anterior funic. And lat funic.
Medulla
Contains primary nuclei for autonom. Control of respiration, heart rate and BP
Spinal trigeminal nucleus, and the spinal trigeminal tract
in the caudal medulla, takes the place of the dorsal horn of sp cord and tract takes the place of the lissauer tract.
Spinal trigeminal nucleus
Receives GSA from the face and external ear, they enter with the trigem nerve and descend alone spinal trigem tract and synapse along its rostral caudal extent.
Tuberculum cinereum
Surface marking in the medulla formed by the spinal tri tract and nucleus, it’s located laterally to the cuneate tract and nucleus
Spinal tri nucleus subdivisions
Pars oralis- crude touch
Pars interpolaris- dental pain
Pars caudalis- pain and temperature input.
Somatotopic organization of pars caudalis
Dorsal corresponds to V3, idle corresponds to V2, and ventral corresponds to V1
Sensory fibers from the external ear travel with CN 7, 9, and 10 to synapse in the dorsal ,oust part of the pars caudalis.
Accessory nucleus
At level of pyramidal decussation, descends down to about the level of c6.
Contain GSE fibers that ascend throughout the foremen magnum and exit to Innervate the SCM and trap
Cortical input for SCM and trap are ipsilaterally and crossed resp.
Dorsal column neurons
Ascend to synaps in the gracile and cuneate nuclei.
Sensory decussation.
Dorsal column nuclei send axons that arc across the tegmentum to join the medial lemniscus. The arcing fibers are called internal architect fibers.
Accessory cuneate nucleus,
receives proprioceptive input from upper extremity that is destine for the cerebellum.
Cuneocerebellar tract
Ascends from the accessory cuneate nucleus to convey proprioception to the cerebellum via inferior cerebellar peduncle.
Blood supply to the lower medulla
Anterior spinal a anteriorly, vertebral a. Anterolaterally, and posterior sp a. More rostrally it is PICA.
Area postrema
Circumventrivular organ, contains sinusoid capillaries, Chemosensitive zone for trigger of emesisstimulated by blood born chemicals
Restiform body
Located dorsolaterally, and provides a major pathway of afferents from the spinal cord and medulla to the cerebellum.
Central tegmental nucleus
Local communication pathway within the brain stem.
Ventral trigeminothalamic tract
Developes lateral to the medial lemniscus, caries pain and temp from the face, originates in the spinal trigeminal nucleus and goes to the thalamus.
Principal olivary nucleus
Involved in planned or skilled voluntary movements primarily cortical afferents
Medial and dorsal accessory olive
Predominantly spinal afferents
Inf olivary complex
Output fibers go to the cerebellum through contra lateral inf cerebellar peduncle.
Hypoglossal
Cortical Innervation is bilateral with a contra lateral dominance. Allows recovery from a one sided lesion.
Contains GSE fibers that mostly Innervate the muscles of the tongue.
Nucleus ambiguous
Contains SVE fibers for inervation of pharyngeal arches, located between spinal trigeminal and inferior oliv. Cortical inervation is bilateral.
Dorsal motor nucleus of vagus
GVE fibers will travel with vagus o synapse on ganglia near organs in Thor and abd.
Receives input from solitary nuc and plays a roll in the barre petrol reflex.
Solitary nucleus
Has two parts, rostral gustatory zone, receives SVA from 7 11 and 10. Sends fibers along central trigeminal tract to thalamus where it projects to the brain for conscious appreciation of taste.
Cauda cardiorespiratory zone- receives GVA from 9 and 10
Vestibular nuclei
The inferior and medial vestibular nuclei are involved in balance equilibrium and movement of the eye. Found in rostral, dorsal, lateral aspect of the medulla. Damage will cause vertigo, nausea, nystagmus.
Nucleus prepositous
Involved in visual fixation on objects.
Inferior saliva tort nucleus
Origin of parasympathetic motor fibers to the parotid gland
Receives influences from hypothalamus and olfactory system
