Overview of Brainstem Organisation Flashcards
What is the brainstem a gateway between?
Spinal cord and higher cortical areas
Why do anencephalic babies survive?
Born without forebrain Have brainstem - Breathe - Suckle - Swallow - Cry
What are the functions of the brainstem?
Reflexive and unconscious behaviour
Modulation of arousal and conscious states
What are the parts of the brainstem?
Midbrain
Pons
Medulla oblongata
Which part of the brainstem is most rostral and continuous with the structures above it?
Midbrain
Which part of the brainstem is most caudal and continuous with the spinal cord?
Medulla
In which cranial fossa is the brainstem?
Posterior
What is the rostral to caudal boundary of the brainstem?
Mammillary bodies rostrally to pyramidal decussation caudally
Describe the dorsal aspect of the midbrain
Two pairs of bumps = superior and inferior colliculi
What are the superior colliculi important for?
Eye movement control
What are the inferior colliculi important for?
Hearing
Describe the dorsal aspect of the pons
Linked with cerebellum via cerebellar peduncles
Limited by 4th ventricle
What are the cerebellar peduncles?
White matter tracts
Where cerebellum joins rest of brain
Describe the dorsal aspect of the medulla
Caudally, dorsal columns and nuclei:
- Gracile and cuneate fasciculus
What happens at the gracile and cuneate fasciculi?
Synapse of spinothalamic tract, carrying somatosensory info
Describe the ventral aspect of the midbrain
Cerebral peduncles between interpeduncular fossa
What are the cerebral peduncles?
White matter tracts coming down from cerebrum and out carrying corticospinal tracts = motor information
Describe the ventral aspect of the pons
Attached to cerebellum dorsolaterally by cerebellar peduncles
- Superior
- Middle
- Inferior
Describe the ventral aspect of the medulla
Rostrally, two bulges = inferior olivary nuclei
Pyramids descending to pyramidal decussation
What are the inferior olivary nuclei important for?
Hearing
What is the tectum?
Roof
Another name for 4 superior and inferior colliculi
Only applies to midbrain
What is the tegmentum?
Most of action of brainstem
Continuous with spinal cord
Where are the cranial nerve nuclei?
Dorsal tegmentum
What is in the basus of the brainstem?
Nuclei and long fibre tracts containing motor control to body
Where is the motor control of the body in the brainstem: dorsally or ventrally?
Ventrally
Where is the reticular formation?
Tegmentum
What do cranial nerves supply?
Somatic and visceral motor and sensory information to head