Brainstem Overview Flashcards
Brainstem starts and ends where?
mamillary bodies rostrally
pyramidal decussation caudally
2 big functions of brainstem
reflexes/unconscious behaviours
modulation of arousal/conscious states
what are the 2 pairs of bumps on the midbrain called? for what?
superior and inferior colliculi
eye movement and hearing
what linked with cerebellum?
pons
pons is limited by what structure?
4th ventricle
what is on the floor of the 4th ventricle?
facial colliculi
- abducens nucleus
- fibres of CN VII
what is located caudally on the medulla
dorsal columns
nuclei: gracile/cuneate
midbrain have massive what matter tracts called? for what?
cerebral peduncles connecting cerebrum to midbrain
how is the cerebellum attached to the pons?
via 3 peduncles
superior
middle
inferior
medulla rostrally
- contains 2 bulges, they are?
- what of the pyramids?
- olivary nuclei
2. pyramidal decussation
what is the tectum?
‘roof’ of the brainstem. ie. midbrain
what is tegmentum?
continuous with spinal cord
what do you find in the tectum?
colliculi of the midbrain
what do you find in the tegmentum? 2 things
cranial nerves
reticular formation
what do you find in the basis?
descending motor pathways
corticospinal
cerebellum
generally the ventral basis has what? vs. dorsal?
ventral: motor
dorsal: cranial nerves and nuclei
general somatic nerves innervate 2 things?
skeletal muscle
skin
general visceral nerves innervate 3 things
smooth muscle
blood vessels
glands
what does the C1 dermatome innervate?
NOTHING.
cranial nerves do what?
supply somatic and visceral motor/sensory info to head
Which CN are exclusively motor?
CNIII, IV, VI Eyes
CN XI, XII
Which CNs are exclusively sensory?
CN I, II, VIII
which CNs are mixed?
V
VII
IX
X
What is the rule of 4 for CNs?
Midbrain: 3-4 (1-2 above midbrain)
Pons: 5-8
Medulla: 9-12
where do cranial nerve nuclei sensory develop from?
Alar Plate
during embryological development, cranial nerve nuclei lie where?
adjacent to ventricular system
where do cranial nerve nuclei motor develop from?
basal plate
cranial nerve nuclei, which are lateral? which are medial?
lateral: sensory
medial: motor
how many columns for cranial nerve nuclei?
6
3 motor: medial
3 sensory: lateral
what are the 3 cranial nerve nuclei motor columns?
general somatic
branchial motor
general visceral
what are the 3 cranial nerve nuclei sensory columns?
general and special visceral
general somatic
special somatic
What is reticular formation in the tegmentum?
millions of neurons communicating with each other to regulate cranial nerve nuclei function
rostral reticular formation does? where?
alert conscious state
midbrain/upper pons
Caudal reticular formation does? where?
reflexes, autonomic functions
pons/medulla
rostral reticular formation does 2 things
ascending reticular activating system
long projection fibres (NT determined)
where is the ventrolateral medullary reticular formation?
caudal reticular formation
what does the ventrolateral medullary reticular formation do viscerally? how?
Vagus:
GI: swallow/vomit
Resp: cough, rhythm, sneeze, hiccup
cardio: HR
3 major pathways in long fibre tracts?
Ascending: Dorsal column/anterolateral
descending: corticospinal
What is the dorsal column medial lemnicus system for? crosses?
light touch, vibration,
crosses caudal medulla
Anterolateral system for what crosses?
pain/temp
crosses in spinal cord
corticospinal tract for?crosses?
motor function
crosses pyramidal decussation
pyramidal decussation which tract?
corticospinal
pain/temp is received by which system?
anterolateral
Dorsal brainstem generally contains? 2 things:
cranial nerve nuclei
reticular formation
ventral (basis) brainstem generally contains
corticospinal
midbrain: cerebral peduncles
pons: cerebellar peduncles
medulla: olivary nuclei
