Brain Stem and Cranial Nerves Flashcards
3 Main Sections of the Brainstem
- Midbrain
- Pons
- Medulla
4 Tracts that Originate in the Brainstem
- Tectospinal
- Rubrospinal
- Reticulospinal
- Vestibulospinal
“2” Sections of the Brainstem
- Basilar
- Tegmentum
- Tectum (posterior section of midbrain)
Term: located in the anterior portion of the brainstem and contains predominately motor system structures
Basilar Section
Term: Contains descending motor axons from the cerbral cortex and motor nuclei
Basilar Section
Term: Located in the posterior portion of the brainstem
Tegmentum Section
Term: Contains the reticular formation, sensory nuclei and ascending tracts, CN nuclei, and the medial longitudinal fasciculus
Tegmentum Section
Term: Tract that coordinates eye and head movement
Medial longitudinal fasciculus
Term: Contains the pretectal area, superior/inferior colliculi, and reflexive control of eye and head movement
Tectum
Term: Reflexive turning of the head, auditory and visual information
Superior and Inferior Colliculi
Term: Adjusts general activity of the nervous system - alerting and arousal
Reticular Formation
3 Main Functions of the Reticular Area
- Integrates sensory and cortical information
- Regulates somatic motor actvity, autonomic function, and consciousness
- Modulates nociceptive information
4 Major Reticular Nuclei
- Ventral tegmental area
- Pedunculopontine nucleus
- Raphe nucleus
- Locus cereleus and Medial reticular area
Structure: Anterior surface includes pyramids, olives, and CNs (IX, X, XI, XII)
Medulla
Structure: Posterior surface includes inferior cerebellar peducnles and central canal
Medulla
Structure: Where corticospinal tracts travel
Pyramids
Structure: Functions to influence cerebellar activity
Olives
Structure: White fiber pathways
Inferior cerebellar peduncle
3 Functions of the Medulla
- Contributes to control of eye and head movement
- Coordinate swallowing
- Helps regulate CV, respiratory, and visceral activity (CN X)
Identify the Spinal Segment and List Defining Features
Inferior Medulla
Features:
- Central Canal
- Fasciculus Gracilis/Cuneatus
- Nucleus Gracilis/Cuneatus
- Medial Lemniscus
- Pyramids
Identify the Spinal Segment and List Defining Features
Upper Medulla
Features:
- Fourth Ventricle
- CN X
- CN XII
- Inferior Olivary Nucleus
Identify the Spinal Segment and List Defining Features
Inferior Pons
Features:
- CN VI
- CN VII (travels posterior and wraps around)
- CN VIII
Identify the Spinal Segment and List Defining Features
Mid/Upper Pons
Features:
- CN V
Identify the Spinal Segment and List Defining Features
Lower Midbrain
Features:
- Inferior Colliculus
- Cerebral Aqueduct
- Para-adqueductal Gray
- CN IV Nuclei (only one that exits posterior)
Identify the Spinal Segment and List Defining Features
Upper Midbrain
Features:
- Superior Colliculus
- Red Nucleus
- CN III Nuclei
3 Tracts Effected by an Anteriormedial Lesion in the Upper Medulla
- Corticospinal (contralateral motor deficits and UMN sx)
- Medial Leminiscus (contralateral conscious proprio/discrim touch deficits)
- Hypoglossal n. (ipsilateral tongue deviation)
Term: Lesion to one side of the brainstem that effects CN III, CN VI, OR CN XII AND the nearby corticospinal tract
Alternating Hemiplegia
Describe why alternating hemiplegia has its name
Pts. present with UMN sx on the opposite side of the lesion and LMN sx on the same side of the lesion
Describe damage to which areas cause the UMN sx and which areas cause the LMN sx in alternating hemiplegia
Damage to the corticospinal tract causes contralateral UMN sx
Damage to the CN causes ipsilateral LMN sx
