Brainstem Region Flashcards
What 3 vertical tracts travel through the brainstem?
Sensory, autonomic, and motor
What are the 2 longitudinal sections of the brainstem?
basilar and tegmentum
Midbrain has an additional longitudinal section, posterior to the tegmentum, called what?
the tectum
The tectum includes structures involved in what?
reflexive control of intrinsic and extrinsic eye muscles and in movements of the head
The basilar is located ____ and contains mostly ____ system structures.
anteriorly
motor
List the structures running through the basilar part of the brainstem
- Descending axons from the cerebral cortex (corticospinal, corticobulbar, corticopontine, corticoreticular tracts)
- Motor nuclei (substantia nigra, pontine nuclei, inferior olive)
- Pontocerebellar axons
The tegmentum is located ____
posteriorlyy
List the structures located in the tegmentum part of the brainstem
- The reticular formation
- Sensory nuclei and ascending sensory tracts
- Cranial nerve nuclei
- The medial longitudinal fasciculus (MLF)
What 3 things does the reticular formation do?
- Integrates sensory and cortical information
- Regulates somatic motor activity, autonomic function, and consciousness
- Modulates nociceptive (pain) information
What are the 4 major reticular nuclei?
- Ventral tegmental area (VTA)
- Pedunculopontine nucleus (PPN)
- Raphe nuclei
- Locus ceruleus and medial reticular area
The ventral tegmentum produces what NT?
dopamine
Activation of the ventral tegmental area affects what? What does this produce
the ventral striatum, which produces feelings of pleasure and reward
The pedunculopontine nucleus produces what NT?
ACh
Where do ascending axons from the PPN project to?
the inferior part of the frontal cerebral cortex and intralaminar nuclei of the thalamus
The PPN influences movement via what 3 connections?
- Globus pallidus and subthalamic nucleus
- Limbic system
- Reticular areas that give rise to reticulospinal tracts
The raphe nuclei produce what NT?
Serotonin
Where do the raphe nuclei supply serotonin to?
the cerebral cortex, thalamus, tectum, cerebellum and spinal cord
What NT does the locus ceruleus and medial reticular area produce?
Norepinephrine
What do the ascending axons of from the locus ceruleus provide?
The ability to direct attention
What do the descending axons of from the locus ceruleus form?
the ceruleospinal tract as part of non-specific UMNs
What does the medial reticular zone regulate?
autonomic functions (cardiovascular, respiratory and visceral)
What are the main effects of dopamine?
- pleasure seeking
- motor control (movement)
- hunger
What are the main effects of serotonin?
- impulsivity
- moral decision making
- obsessive-compulsive
What are the main effects of norepinephrine?
sympathetic stimulation (fight or flight)
Define Consciousness
awareness of self and surroundings
What does the consciousness system govern?
alertness, sleep, and attention
What are the brainstem components of the consciousness system?
The reticular formation and its ascending reticular activating system
What are the 2 vertical bulges on the medulla called?
pyramids
What are the 2 small, oval lumps lateral to the pyramids called?
olives
Which cranial nerve connects with the medulla between the pyramid and the olive?
XII
What axons form the pyramids in the lower medulla?
the descending axons of the corticospinal tract
In the upper medulla the tracts that are located in the rostral part of the medullar are in approximately the same positions except for which one?
The medial longitudinal fasciculus (MLF) which is located more posteriorly
Most CN nuclei in the rostral medulla are clustered in the ____ section
dorsal
What are the 3 functions of the medulla?
- Controlling head movements
- Coordinating swallowing
- Helping regulate cardiovascular, respiratory, and visceral activity
What are the only 2 tracts that synapse in the pons?
- conticopontine
- some corticobrainstem
The pons process motor information from where? Where does it forward information to?
from the cerebral cortex and forwards the information to the cerebellum
Pontine CN nuclei control contraction of muscles involved in what? What are the associated cranial nerves?
- Facial expression (cranial nerve VII)
- Lateral movement of the eye (cranial nerve VI)
- Chewing (cranial nerve V)
The midbrain connects the pons to what structure?
the diencephalon
What are the 3 regions of the midbrain from anterior to posterior?
- Basis pedunculi
- Tegmentum
- Tectum
What structure is formed by the cerebral peduncles and the substantia nigra?
Midbrain Basis Pedunculi
What does the midbrain tegmentum contain?
- sensory tracts
- superior cerebellar peduncle
- red nucleus
- PPN
- the nuclei of cranial nerves III and IV
What does the midbrain tectum contain?
- the pretectal area
- the colliculi
What reflexes is the pretectal area involved in?
The pupillary, consensual, and accommodation reflexes of the eye.
What do the inferior colliculi do?
relay auditory information from the cochlear nuclei to the superior colliculus and to the medial geniculate body of the thalamus
What are the superior colliculi involved in?
reflexive eye and head movements
The function of which brain structure is completely dependent on input and output connections with the brainstem?
Cerebellum
What are the 3 cerebellar functions?
- Coordination of movement
- Motor planning
- Cognitive functions, including rapid shifts of attention
