Brain Stem and Cranial Nerves Flashcards
Brainstem
Where most of the cranial nerves are coming and leaving
Brainstem Function
Has sensory, autonomic and motor tracts that travel through or synapse
Ascending Tracts in Brainstem
Modified in dorsal portion of brainstem
Spinothalamic Modification
Not modified
Passes through brainstem without alteration
Dorsal Column Modification
Axons synapse in nucleus gracilis or cuneatus
2nd order neuron cross midline to form medial lemniscus
Descending Tracts in Brainstem
Modified in anterior portion of brainstem
Corticospinal Modification
Not modified
Passes through brainstem without alteration
Corticobulbar Modification
Axons synapse with cranial nerve nuclei in brainstem
Conscious control of cranial nerves
Corticoreticular Modfication
Axons synapse within reticular formation
Some control over reticular area
Tracts Originating in Brainstem
Tectospinal
Rubrospinal
Reticulospinal
Vestibulospinal
Basilar Section of Brainstem
Located anterior and contains motor system structures
Tegmentum Section of Brainstem
Located posterior
Basilar Section contains…
Descending axons from cerebral cortex
Motor nuclei
Tegmentum Section contains…
Reticular formation
Sensory nuclei and ascending sensory tracts
Cranial nerve nuclei
Medial longitudinal fasciculus
Medial Longitudinal Fasciculus Tract
Coordinates eye and head movement
Tectum Section contains…
Pretectal area - optic reflexes
Superior and inferior colliculi
Reflexive control of eye and head
Reticular Formation
Adjusts general activity of nervous system
Reticular Formation Function
Integrates sensory and cortical function
Regulates somatic motor activity/autonomic function/consciousness
Modulates nociceptive information
Major reticular nuclei
Ventral tegmental
Pedunculopontine
Raphe nucleus
Locus cereleus and medial reticular area
Ventral Tegmental Area Function
Provides dopamine
Important in motivation and decision making
Pedunculopontine Nucleus Function
Influences movement via connections to thalamus and vestibular/reticular nuclei
Raphe Nucleus Function
Affects mood
Involved in inhibition of pain transmission
Locus Cereleus and Medial Reticular Area Function
Regulates attention
Regulates autonomic function
Medulla Anterior Surface
Pyramids
Olives
Cranial nerves IX, X, XI, and XII
Medulla Posterior Surface
Inferior cerebellar peduncle
Central canal widens to become 4th ventricle
Inferior Cerebellar Peduncle Function
White fiber pathway where information goes into cerebellum
Medulla Functions
Contributes to control of eye and head
Coordinates swallowing
Helps regulate cardiovascular, respiratory and visceral activity
Inferior Olivary Nucleus (Superior Medulla)
Relay information to cerebellum
Corticobulbar Tract Pathway
Motor cortex
Projects to CN nuclei in brainstem
Facilitates LMN innervating muscles of head and neck
Project laterally
Corticobulbar Tract Exception
LMN’s to lower face and tongue muscles controlled by contralateral fibers
Brainstem Disorders
Mix of ipsilateral and contralateral signs
Mix of UMN’s and LMN’s
Four D’s (-phagia, -arthria, -poplia, -metria)
