org. of brainstem Flashcards
____________ : all the ascending and descending pathway fibres have to pass through here to get to the brain
Conduit
Cranial Nerves ____ and ____ are not attached to brainstem
1 and 2
one function of brianstem is ____________
Integration : respiration , cardiaovascular, control, consciousness, sleep (reticular functions)
There are 3 subdivisions of brainstem ______ , __________ and _________
3 main subdivisions of brainstem:
Midbrain (rostral and caudal)
pons “bridge” (rostral and caudal)
Medulla (rostral and caudal)
Medulla has two subdivions :
____ and ____
Medulla (rostral and caudal):
- caudal is “closed” and only flows with spinal cord, rostral end is “open to fourth ventricle”
- Obex - where 4th ventricle becomes continues with central canal (a “V”)
the ___________ contains the pyramids together with part of the central canal. in its caudal half and part of the fourth ventricle in its rostral half.
medulla
the________ contains the basal pons and part of fourth ventricle but only the caudal pons is physically attached too the cerebellum
pons
the_________ contains cerebral peduncles and cerebral aqueduct and superior and inferior Colliculi
midbrain
_________ on posterior side of mid brain, _______ in middle and _________ on anterior side.
Tectum , tegmentum, cerebral peduncles
In the pons no _______ , _______ now posterior side, and pons is anterior “appendage”
tectum, tegmentum
____________ still the posterior side in medulla , pons is gone, the ______ are anterior side with the _________
tegmentum , pyramids , olives
Define the 3 major pathways and their functions
Corticospinal tract (voluntary movement)
Spinothalamic tract (pain and temperature)
Posterior columns (touch sensation and proprioception)
-__________ descends from motor strip down to spinal cord (on anterior side of brain stem). Through the _______ , _____ , and ______ , the fibers cross at the ________ and head down the spinal cord as the lateral __________ .
Corticospinal tract (voluntary movement) - descends from motor strip down to spinal cord (on anterior side of brain stem). Through the internal capsular cerebral peduncles, basal pons, and pyramids, the fibers cross at the spinomedullary junction and head down the spinal cord as the lateral corticospinal tracts.
_____________ - ascends from spinal cord up through brainstem to the thalamus (on anterior lateral side of Tegmentum)
Spinothalamic tract (pain and temperature)
_____________ - ascend the posterior spinal cord and end in the medulla (in the gracilis nucleus and the cuneatus nucleus) to become medial lemniscus which ascends to the thalamus.
Posterior columns (touch sensation and proprioception)
Define gneral features of Caudal Medulla
1- Caudal Medulla (Closed end)
end of spinal cord.
from cuneatus and gracilis nucleus fibers cross the midline and form the contralateral medial lemniscus (this is the sensory crossing)
spinothalamic tract in the tegmentum
Pyramid append off the anterior side,
Reticular formation in the center.
Define the general features of Rostral Medulla
- Rostral Medulla (open end)
section from obex to cerebellar peduncles
contains the inferior olivary nucleus and part of Forth Ventricle
Define general features of Caudal Pons
Caudal Pons
Physically connected to the cerebellum btw the cerebellar peduncles
Inferior olivary nucleus ends medial lemniscus still here,
lots of fibers here (pyramidal tract, spinothalamic, CST .. )
Fibers originate and go to cortex
Pons is bridge (to Cb, from brain to spinal cord, left/right crossings)
Define general features of Rostral pons
Rostral pons
- Not directly connected to Cb, still touches 4th ventricle, cerebral aquaduct.
- Pons has several nuclei and crossing tracts, major fiber crossing center (like CC)
Define general features of Caudal Midbrain
Caudal Midbrain
Tectum = superior and inferior colliculi
caudal midbrain contains inferior collicuulo (auditory)
superior cerebellar peduncles cross here
periaquaductal gray begins (pain control)
pons is gone now and instead is cerebral peduncles (where the CST travels)
Define general features of Rostral midbrain
Rostral midbrain
contains superior colliculi (vision)
red nucleus and substantia nigra (important brainstem nuclei)
thalamus and spinal glad are nearby
______________ : Not so much a structure but a collection of connections that meme the core of the brainstem
Reticular formation
what are the three major zones of Reticular formation
Three major zones :
Raphe nuclei (“seam” on midline)
Gigantocellular reticular nucleus (or medial zone)
Lateral zone (reflexes and visceral functions)
Reticular formation has two reticulospinal tracts:
1- ___________. - (orientation ? )
2- ___________ - (orientation ?)
1- pontine reticularspional tract. - medial
2- medullary reticuspino reat - lateral
______________ help control motor system especially motor reflexes that do not have to travel to cortex and makes sure only noxious stimuli can cause a reflex (hand in fire)
Reticular formation
___________ can also modulates pain.
- internal pain suppression mechanism
stimulation of ______________ is powerful analgesic
stimulation can treat otherwise intractable pain
___________ (and other opiates) work by stimulation the ____________ ….
Reticular formation : modulates pain
internal pain suppression mechanism
stimulation of periaquaductal gray is powerful analgesic
stimulation can treat otherwise intractable pain
morphine (and other opiates) work by stimulation the periaquaductal gray ….
_______________ serve Visceral reflexes : autonomic control of breathing , heart rate, blood pressure.
Reticular formation : Visceral reflexes
autonomic control of breathing , heart rate, blood pressure.
______________ also serves in sleep and consciousness , arousal / attention
the part of RF involved in this is the __________________
damage to ARAS induces ____________
ARAS can also regulate _________________
also involved in ______________.
Reticular formation : sleep and consciousness , arousal / attention
the part of RF involved in this is the ARAS (ascending reticular activating system)
damage to ARAS induces coma
ARAS can also regulate sleep-wake cycle
also involved in arousal/attention.
______________ are the base of most Neurotransmitter system
especially the __________ NTs ( norephin … dopamine, sera ) and ________
____________ also produces in the brain stem
Brainstem nuclei are the base of most NT system
especially the biogenic amine NTs ( norephin … dopamine, sera ) and histamines
aceylochlione also produces in the brain stem
_____________ neurons only found in pons and medulla.
- most of locus ceruleus “blue spots” (in rostral pons) - theses neurons go to the cortex
- some in medullary reticular formation - these go to spinal cord.
may play a role in vigilance …
norepinephrine neurons only found in pons and medulla.
most of locus ceruleus “blue spots” (in rostral pons) - theses neurons go to the cortex
some in medullary reticular formation - these go to spinal cord.
may play a role in vigilance …
_______ neurons in ________ and ________ , _______ projects to frontal and limbic cortex (mesocortical and mesolimbic fibers)
SN has two parts: ________ and _________
SN projects fibers to the caudate/putamen (stratum) called __________
DA in PEC controles ___________
DA neurons in substtantia nigra and ventral tegmental area (VTA ) , VTA projects to frontal and limbic cortex (mesocortical and mesolimbic fibers)
SN has two parts: pars compacta and parts reticularis
SN projects fibers to the caudate/putamen (stratum) called nigrotrital fibers
DA in PEC controles motor initiation. . DA in limbic … etc
etc
Raphi nucleus - seratonin
seratonin neurons are concentrated in the _________ and project widely across the whole brain
____________ project to forebran and concentrate on limbic and sensory areas
____________ project to Cb, brainstem, spinal cord
Firing rates fluctuate with sleep/wake so likely help regulate arousal , likely the level of “depression” …
Raphi nucleus - seratonin
seratonin neurons are concentrated in the raphi nucleus and project widely across the whole brain
rostral raphi nuclei project to forebran and concentrate on limbuc and sensory areas
caudal raphi nuclei project to Cb, brainstem, spinal cord
Firing rates fluctuate with sleep/wake so likely help regulate arousal , likely the level of “depression” …
rostral brainstem and basal formation - acetycholine
Ach is widespread an ______________
CNS (muscarinic) more focal : in _______ and __________ (nucleus basalis , septal nuclei, substantia innominata) some in caudata and putamen.
__________ system implicated in Alzherinemr’s , sleep/wakem and learning / memory.
rostral brainstem and basal formation - acetycholine
Ach is widespread an PNS motor system (nicotinic)
CNS (muscarinic) more focal : in retucular formation and basal forebrain (nucleus basalis , septal nuclei, substantia innominata) some in caudata and putamen.
Basal froebrain cholineregic system implicated in Alzherinemr’s , sleep/wakem and learning / memory.
Brainstem Blood Supply
perfused by the _____________
gives rise to _____________ (wraps around brainstem)
midbrain also supplied by PCA gives territories that generally map onto brainstem stroke locations.
Brainstem Blood Supply
perfused by the vertebral-basilar artery system
gives rise to circumferential artery system (wraps around brainstem)
midbrain also supplied by PCA gives territories that generally map onto brainstem stroke locations.
