Brain stem Flashcards
Receives blood supply from
vertebrobasilar system
central core
reticular formation
brainstem three broad functions
conduit for the ascending tracts and descending tracts
reflex centers associated with the control of respiration and the cardiovascular system
contains the important nuclei of cranial nerves III through XII
Midbrain CN
3, 4
Pons CN
5, 6, 7, 8
Upper Medulla CN
9, 10, 11, 12
Medulla Oblongata
Supplied by PICA
Contains:
- cardiovascular center
- medullary rhythmicity area of the Respiratory Center
- reflexes for vomiting, swallowing, sneezing, coughing, and hiccupping
Medulla’s white matter contains
all sensory (ascending) tracts and motor (descending) tracts
Pons blood supply and two major structural components
supplied by basilar artery
a ventral region and a dorsal region
ventral region of the pons
forms a large synaptic relay station consisting of scattered gray centers called the pontine nuclei
Other nuclei located in the pons
Pneumotaxic area and the Apneustic area
Mid brain blood supply and tectum
supplied by PCA
four rounded elevations
two superior elevations, (superior colliculi), serve as reflex centers for certain visual activities
two inferior elevations (inferior colliculi) are part of the auditory pathway
Lateral Medullary Syndrome of Wallenberg
supplied by the posterior inferior cerebellar artery
- Dysphagia and dysarthria
- Analgesia and thermoanesthesia on the ipsilateral side of the face
- Vertigo, nausea, vomiting, and nystagmus
- Ipsilateral Horner syndrome
- Ipsilateral cerebellar signs
- Contralateral loss of sensations of pain and temperature
Medial Medullary Syndrome
supplied by the posterior inferior cerebellar artery
- Contralateral hemiparesis
- Contralateral impaired sensations of position and movement and tactile discrimination (medial lemniscus)
- Ipsilateral paralysis of tongue muscles with deviation to the paralyzed side when the tongue is protruded (hypoglossal nerve)
Pontine Hemorrhage
supplied by the basilar artery
- pupils may be pinpoint
- facial paralysis on the side of the lesion
- paralysis of the limbs on the opposite side
Infarctions of the Pons
due to thrombosis or embolism of the basilar artery
Weber Syndrome
*** an ipsilateral oculomotor paralysis, coupled with a contralateral upper motor neuron paralysis
- dilated, unresponsive pupil, a drooping eyelid, and an eye that deviates downward
Benedikt Syndrome
*** ipsilateral paralysis of the oculomotor nerve as well as a tremor of the opposite limb, coupled with possible somatosensory loss in the contralateral side of the body
Gaze Palsy (Pariaud’s Syndrome)
- upward gaze paralysis, possible nystagmus with downward gaze, light-near dissociation, large pupil, abnormal elevation of the upper lid, and paralysis of accommodation
corticospinal tract
contralateral weakness
medial lemniscus
loss contralateral proprioception/ vibration
medial longitudinal fasciculus
ipsilateral INO
motor nucleus and nerve
ipsilateral CN motor loss (CN 3, 4, 6, 12)
spinocerebellar tract
ipsilateral ataxia
