Neuro L3 Flashcards
Brainstem functions (3)
Conduit: info goes to cortex and spinal cord
Cranial nerve:
Integrative functions: motor patterns, cardioresp. control, reflexes
Caudal medulla contains
Central canal continuous with central canal of spinal cord
Rostral end of medulla contains
central canal expand into fourth ventricle
Obex
apex of fourth ventrical where it narrows to central canal
Pyramidal decussation
Interrupts
Contains
Bounded by
interrupts anterior median fissure
Contains corticospinal tract
Bounded by anterolateral sulcus
Olive
Bulge created by inferior olivary nucleus
CN associated with Medulla
IX, X, XII
Superior cerebellar peduncle
Part of
Forms much of roof of
Part of pons
Forms much of roof of fourth ventricle
Cerebral aqueduct
Connects
Connects 3rd and 4th ventrical
Superior colliculus
location
Rostral midbrain
Inferior colliculus
location
Caudal midbrain
Cerebral peduncles
location
Type of matter
white matter at base of midbrain
Inferior brachium
Location
Midbrain
All brainstem levels rostral to ____ have three levels
Obex
Three levels of brainstem rostral to obex
Tegmentum
Tectum
Stuff aded onto anterior surface
Tegmentum
tissue anterior to ventricle
Tectum
Tissue posterior to ventricle
Main fiber tract locations in brainstem (3)
corticospinal tract
Spinothalamic tract
Medial lemniscus
Corticospinal tract
Location
Anterior
Spinothalamic tract
location
anterolateral
Medial Lemniscus
location
medial but more variable
Caudal medulla
Open or closed
Extends from ___ to ____
Closed medulla
Extends from pyramial decussation to obex
Caudal medulla landmarks (4)
Central canal
Gracile nuclei
Cuneate nuclei
Pyramidal decussation
Rostral medulla landmarks (4)
Fourth ventricle
Inferior olivary nuclei
XII nucleus
Pyramids
Caudal pons landmarks (4)
Inferior cerebellar peduncle
Middle cerebellar peduncle
Medial lemniscus
4th ventricle
Rostral pons landmarks (3)
superior cerebellar peduncle
Medial lemniscus close to spinothalamic tract
small ventricular space at aqueduct
Caudal midbrain landmarks (3)
Inferior colliculus
IV
Decussation of superior cerebellar peduncle
Rostral midbrain landmarks (4)
Superior colliculus
III
Red nucleus
Substantia nigra
Sulcus limitans
separates sensory from motor
Reticular formation important in regulation of (6)
sleep/wakefulness Posture pain internal environment Motor behaviors emotion
Longitudinal zones of reticular formation
Raphe
Medial
Lateral
Medial zone
Size of neurons
Source of
large and small neurons
Source of most ascending and descending projections
Lateral zone Prominent in (2) Involved in (2)
Prominent in Rostral medulla Caudal pons Involved in Cranial nerve reflexes Visceral functions
Medial reticulospinal tract
Begins in
sides
descends near ___ in ____
Begins in pons
Ipsilateral
Descends near medial longitudinal fasciculus in anterior funiculus
Later reticulospinal tract
Begins in
sides
descends in
begins in medulla
descends bilaterally
in lateral funiculus
Major alternative to corticospinal tract in regulating spinal motor neurons
Reticular formation
Reticular formation influences spinal motor neurons (directly/indirectly)
directly
Rhythmic motor patterns of brainstem reticular formation
Swallowing/vomiting Heart rate Locomotion Respiration Mastication Gaze centers
Gaze Centers
Location and type
Midbrain: vertical gaze center
Pons: horizontal gaze center
Responsible for mastication
Nucleus and location
Supratigeminal nucleus (pons)
Medulla Vital center (3)
Swallowing/vomiting
Respiration
Heart rate
Bruxism
jaw opening and jaw closing muscles are contracted at same time
Peripheral causes theory of bruxism
(based on clinical)
Malocclusion
Movements in attempt to reach resting position
Central causes theory of bruxism
Sleep related dysfunctions Input to supratrigeminal nucleus may be from basal ganglia, lateral hypothalamus central nucleus of amygdala
Periaquaductal Gray receives pain info from
Spinomesencephalic fibers
PAG gets behavior state info from
hypothalamus, cortex, amygdala
Opiates work by activating
PAG-raphe at multiple levels
Raphe can inhibit spinothalamic tract by
directly
activating interneurons
directly inhibit pain afferents
Raphe uses ____ in synapses
serotonin
For arousal and consciousness, ___ and ____ of RF project to ______ which projects to the ____
Midbrain and Pons
Thalamic intralaminar nuclei
Cortex
_____ damage to the ___ RF results in prolonged coma
Bilateral damage to midbrain
ARAS
name
roles
Ascending reticular activating system
Maintain consciousness
Sleep-wakefulness
Chemicals in brainstem
norepinehphrine
dopamine
serotonin
Chemicals in hypothalamus nuclei
histamine containing neurons
Chemical in telencephalon nuclei
acetylcholine
Norepinephrine nonadrenergic neurons in
Medulla: Solitary nucleus Ventrolateral medulla Rostral Pons: Locus ceruleus
Solitary nucleus, located in, uses this chemical for _____
medulla, norepinephrine for memory enhancement
Ventrolateral medulla uses this chemical for _____
norepinephrine for pain regulation
Locus ceruleus, located in, uses this chemical for
located in pons, norepinephrine for cortex attention
Locus ceruleus releases norepinephrin in the cortex in response to _____ causing____ ____
novel environmental stimuli
Causing arousal, feeling of anticipation
Trigeminal spinal nucleus and spinal cord release norepinephrine from _____ in order to _____
from ventrolateral medulla
Suppress incoming pain signals
Low levels of norepinephrine can cause this condition
depression
Parkinsons patients may suffer from ____ due to _____
depression due to loss of locus ceruleus neurons
High levels of norepinephrin can cause
panic disorder
Dopaminergic neurons in midbrain
substantia nigra (putamen and caudate) ventral tegmental area (limbic system)
substantia nigra has ___ neurons involved in
Dopaminergic neurons
Motor activity
Parkinson deisease
Ventral tegmental area has ___ neurons
dopaminergic
Ventral tegmental area fibers
Mesocortical
Mesolimbic
Mesocortical fibers
Part of this area
Involved in
Ventral tegmental area
Organized thinking, planning;
projections to front cortex
Mesolimbic fibers
Part of this area
Involved in
Ventral tegmental area
Emotional reward
Drug dependency
Schizophrenia components/causes
Social withdrawal: low levels of dopamine in prefrontal cortex
Hallucinations: high levels of dopamine in limbic system
Serotonergic neurons located at _______ in raphe
pretty much all brainstem levels in raphe
Midbrain raphe nuclei communicating w/ serotonin to regions of cortex results in
attention: inhibition of distracting stimuli
Hypothalamus: day-night cycle
Serotonergic projections are extensive and numerous, especially to
sensory and limbic areas
Low levels of serotonin can cause
high carb consumption, binge eating
High levels of serotonin can cause
compulsive behavior/ anoreia nervosa
How does reticular formation regulate spinal reflexes?
only noxious stimuli evoke a reflex
