Flashcards in Overview of Brainstem Organisation Deck (68):
What is the brainstem a gateway between?
Spinal cord and higher cortical areas
Why do anencephalic babies survive?
Born without forebrain
What are the functions of the brainstem?
Reflexive and unconscious behaviour
Modulation of arousal and conscious states
What are the parts of the brainstem?
Which part of the brainstem is most rostral and continuous with the structures above it?
Which part of the brainstem is most caudal and continuous with the spinal cord?
In which cranial fossa is the brainstem?
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?
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
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?
What is the tectum?
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?
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?
Where is the reticular formation?
What do cranial nerves supply?
Somatic and visceral motor and sensory information to head
Where else do CN IX and X supply visceral sensory and motor innervation to?
Most abdominal organs
From which surface do most cranial nerves exit the brainstem?
Which cranial nerve doesn't exit the brainstem ventrally?
Which cranial nerves are exclusively motor?
Which cranial nerves are exclusively sensory?
Which cranial nerves are mixed?
What is the rule of 4s?
4 cranial nerves exit medulla
4 cranial nerves exit pons
4 exit above pons
What determines the location of motor and sensory columns?
What do cranial nerve nuclei lie adjacent to during embryological development?
Which nuclei develop from the alar plate?
Which nuclei develop from the basal plate?
What is the relationship of the alar and basal plates in the spinal cord?
Alar plate becomes dorsal horns
Basal plate becomes ventral horns
What does the fourth ventricle do to the dorsal nuclei during development?
Pushes them laterally
How are nuclei positioned in the brainstem?
How are cranial nerve nuclei grouped?
Based on similar functions
Where are motor nuclei located?
Closer to midline
Where are sensory nuclei located?
How many motor columns are there, and what are they?
- General somatic motor
- Branchial motor
- General visceral
How many sensory columns are there, and what are they?
- General and special visceral
- General somatic
- Special somatic
Which columns are closer to the midline?
Which columns are located laterally?
What is the reticular formation continuous with?
Rostrally, with certain nuclei in thalamus
Caudally, with intermediate grey of spinal cord
What are the rostral functions of the reticular formation?
Higher cortical function
- Maintain alert conscious state
Where is the rostral reticular formation?
Midbrain and upper pons
What are the caudal functions of the reticular formation?
Many tasks of spinal cord but with greater complexity
Work together with cranial nerve nuclei and spinal cord to carry out important motor reflexes and autonomic functions
Where is the caudal reticular formation?
Pons and medulla
How does the reticular formation modulate forebrain activity rostrally?
- Ascending reticular activating system
- Long projection systems
What are long projection systems defined by?
What are some long projection systems?
Noradregernic from locus ceruleus
Dopaminergic from substantia nigra
Serotonergic via dorsal raphe nucleus
What does a lesion in the midbrain mean?
What does the ventrolateral medullary reticular formation do?
Regulate visceral functions CN X
- GI responses
- Respiratory activities
- Cardiovascular responses
What are the lateral medullary anf pontine reticular formations important for?
What is the region surrounding facial nucleus important for?
Which major pathways traverse the brainstem?
Dorsal column-medial lemniscus system
What are the ascending pathways in the brainstem?
Dorsal column-medial lemniscus system
What are the descending pathways in the brainstem?
Describe the dorsal column-medial lemniscus system
Crosses in medulla
Travels medially for the most but veers laterally in midbrain
Describe the anterolateral system
Crosses in spinal cord
Gets close to dorsal column-medial lemniscus pathway in midbrain
Describe the corticospinal tract
Crosses at pyramidal decussation at boundary of brainstem
Upper motor neuron synapses with lower motor neuron in spinal cord
What do the dorsal aspects of the brainstem contain?
Cranial nerve nuclei