Lecture 5- CNS Brainstem Flashcards
What parts make up the brain stem?
- Mesencephalon (midbrain)
- Pons (part of Metencephalon)
- Myelencephalon (medulla oblongata)
The brain stem connects what?
connects diencephalon to spinal cord
MEDULLA=MYELENCEPHALON
MEDULLA=MYELENCAPHALON
The medulla is an extension of the __________ and ends at the __________.
- spinal cord
- metencephalon (pons and cerebellum)
The medulla carries both ________ and __________ fiber tracts.
- ascending sensory
- descending motor
The inferior cerebellar peduncle of the medulla connects the _________ to the __________.
- cerebellum
- spinal cord
The medulla has nuclei for what CN?
What else does it have nuclei for?
- CN8-12
- also has nuclei for vital venters and reticular formation
On the anterior side of the medulla we have paired what?
pyramids
The pyramids of the medulla contain what tracts?
corticospinal- controls movement of torso and extremities
__% of the corticospinal tracts from the cerebrum cross at the decussation and form the _______ corticospinal tract.
- 90%
- lateral
__% of the corticospinal tracts do not cross at the decussation and form the _______ corticospinal tracts. These are our ______ muscles.
- 10%
- medial
- axial
CN_-_ emerge from the spinal cord in the region of the medulla.
CN6-CN12
What is the function of the inferior olivary nuclei?
cerebellar relay center for perception of time
On the posterior side of the medulla we have the paired fasciculus _________ and ________. What are their functions?
- fasciculus cuneatus- carries somatosensory info from trunk and UE
- fasciculus gracilis- carries somatosensory info from LE
There is also an open part on the posterior side of the medulla that is associated with what ventricle?
4th ventricle
What is located at the floor of the fourth ventricle leading to an opening of the central canal?
area postrema
What is the area postrema associated with?
vomit center
The medulla has both gray and white matter. The caudal half of the medulla is considered the _______ medulla, this is where we find the ___________.
- closed
- central canal
List the fiber tracts located at the level of pyramidal decussation (closed medulla) and their function. SLIDE 12
- corticospinal
- decussation of pyramids
- fasciculus gracilis
- fasciculus cuneatus
- spinothalamic
- anterior spiinocerebellar
- posterior spinocerebellar
- CN5 spinal trigeminal tract
Function of the corticospinal tracts?
efferent voluntary from cortex to muscles of trunk and extremities
Function of decussation of pyramids?
crossing point of 90% of corticospinal tracts
Function of fasciculus gracilis and cuneatus tracts?
- fasciculus gracilis- sensory touch and proprioception from legs
- fasciculus cuneatus- sensory touch and proprioception from arms and trunk
Function of spinothalamic tracts?
sensory pain and temperature from trunk and extremities
Function of anterior spinocerebellar tracts?
sensory from thoracolumbar ventral horn to cerebellum
Function of the posterior spinocerebellar tracts?
sensory from legs to cerebellum
Function of the CN5 spinal trigeminal tract and nucleus?
sensory pain and temperature from face
What is the function of the nucleus gracilis and nucleus cuneatus?
relay centers for the tracts
List the fiber tracts located at the level of the medial lemniscus decussation (closed medulla). SLIDE 12
- decussation of medial lemniscus
- pyramids
- CN5 spinal trigeminal tract
- anterior spinocerebellar
- posterior spinocerebellar
- spinothalamic
- medial longitudinal fasciculus
What happens at the decussation of the medial lemniscus?
crossover point for ascending fibers for proprioception and tactile sensation from the nuclei gracilis and cuneatus ie. dorsal column tracts
What is the function of the medial longitudinal fasciculus?
balance coordinator
List the nuclei located at the level of the medial lemniscus decussation (closed medulla).
- nucleus gracilis
- nucleus cuneatus
- accessory cuneate nucleus
- CN5 spinal trigeminal nucleus
- reticular formation
- inferior olivary nuclei
- nuclei ambiguous
The nucleus gracilis and nucleus cuneatus act as ______ points for touch, pressure, proprioception from legs, arms, and trunk.
-relay
The accessory cuneate nucleus is helping to relay information about the _____ to the cerebellum. It forms what tract?
- arms and trunk
- cuneocerebellar tract
What is the function of the reticular formation?
- modulates sensory signaling to cortex
- filters sensory information
- helps with consciousness, sleep/wake
- emotions
- modulates motor signaling
What is the function of the nucleus ambiguous?
CN9 and CN10 motor for swallowing, going to pharyngeal muscles
The open medulla is where the central canal is replaced with the ___________.
4th ventricle
Neurons found in the basal plate are _____.
Are the basal plate neurons found lateral or medial at the open medulla?
- motor
- medial
What are the nuclei at the basal plate from medial to lateral?
- hypoglossal nuclei (CN12)
- nuclei ambiguous (CN9 and 10)
- dorsal motor nuclei (CN10)
- sulcus limitans
The hypoglossal nuclei is CN__ and contains _________ to skeletal muscle of the _______.
- 12
- somatomotor
- tongue
The nuclei ambiguous is CN_ and _ and contains ____________.
- 9 and 10
- special visceral
The dorsal motor nuclei is CN_ and contains ____________.
- 10
- parasympathetic
What does the sulcus limitans do?
Seperates the medial cranial nerve MOTOR nuclei from the lateral SENSORY nuclei
Neurons found in the alar plate are _________.
Are the alar plate neurons found lateral or medial at the open medulla?
- sensory
- lateral
What are the nuclei at the alar plate from the sulcus limitans laterally?
- sulcus limitans
- solitary nucleus (CN7,9,10)
- spinal nuclei (CN5)
- vestibular nuclei (CN8)
- cochlear nuclei (CN8)
What does the sulcus limitans do?
Seperates the medial cranial nerve MOTOR nuclei from the lateral SENSORY nuclei
- The solitary nucleus contains ___________ from CN9 and 10 for __________ and ___________ input.
- The solitary nucleus also contains ____________ for _____ from CN7,9, and 10.
- viscerosensory
- cardiovascular and respiratory (GVA)
- special sensory (SVA)
- taste
The spinal nuclei of CN_ contains _________ of the head.
- CN5
- somatosensory (pain and temp)
The vestibular nuclei of CN_ contains _____________ for _________.
- CN8
- special sensory
- balance
The cochlear nuclei of CN_ contains _______________ for _________.
- CN8
- special sensory
- auditory
What are other fiber tracts located at the open medulla.
- inferior cerebellar peduncle
- medial longitudinal fasciculus with tectospinal tract
- medial lemniscus
- spinothalamic tract
- pyramids
The inferior cerebellar peduncle carries ________ to the cerebellum from _________ and ____________.
- sensory
- spinal cord and medulla
The medial longitudinal fasciculus with the tectospinal tract coordinate movement of the ______ and _____ with vestibular input for overall _______/_________.
- eyes and body
- balance/equilibrium
The last 2 nuclei found in the open medulla are the _____________ and reticular formation.
inferior olivary nuclei
PONS=PART OF METENCEPHALON
PONS=PART OF METENCEPHALON
What are the 2 parts of the pons and their location?
Basilir pons=ventral surface
Pontine tegmentum=dorsal surface and floor of 4th ventricle
The pons is part of the _________ so it contains ____ nuclei and ascending and descending fiber tracts linking ________ to ___________ and spinal cord.
- brain stem
- cranial nerve
- upper brain to medulla
What are the fibers found at the basilir pons?
- transverse pontine
- corticospinal and corticobulbar
The transverse pontine relay _________ signals to the ____________ via ________ _________ peduncle.
- sensory
- cerebellum
- middle cerebellar
The corticospinal and corticobulbar tracts run ______________ through the basilir pons
longitudinally
The only nuclei found in the basilir pons is what?
deep pontine nuclei
What are the fiber tracts of the tegmental pons?
- facial colliculus
- superior cerebellar peduncle
- middle cerebellar peduncle
- inferior cerebellar peduncle
- medial lemniscus
- medial longitudinal fasciculus
- spinothalamic
- trigeminothalamic
- lateral lemniscus
- rubrospinal tract
- tectospinal tract
- CN5 spinal nucleus tract
- descending limbic and hypothalmic fibers
The facial colliculus contains ________ fibers
facial nerve CN7
The superior cerebellar peduncle carries ________ from the cerebellum to the brain stem and cerebral cortex.
-motor (efferent)
The middle cerebellar peduncle carries _________ from the cerebral cortex to the cerebellum.
sensory (afferent)
The inferior cerebellar peduncle carries _________ from the medulla and spinal cord to the cerebellum.
sensory (afferent)
The trigeminothalamic carries ________ from the head to the cortex
somatosensory (afferent)
The lateral lemniscus is the ________ relay circuit to the ________ colliculus for __________ reflex movement of the head.
- auditory
- inferior
- auditory
The descending limbic and hypothalalmic fibers go to _______________________ in the medulla and spinal cord.
autonomic control centers
What nuclei are located at the caudal pons?
- facial nucleus CN7
- abducens nucleus CN6
- spinal trigeminal nuc. CN5
- superior olivary nuc.
- trapeziod body
- medial and inferior vestibular nuc.
- superior salivatory nuc.
What does the facial nucleus of CN7 control?
muscles of facial expression
What does the abducens nucleus of CN6 control?
eye muscles (lateral rectus)
What does the superior olivary nuclei do?
relay in auditory pathway
What does the trapezoid body of the pons do?
relay in auditory pathway
What nerve are the medial and inferior vestibular nuclei associated with?
CN8
What does the superior salivary nuclei do?
part of CN7 to lacrimal, submandibular, and sublingual salivary glands
What nuclei are located at the rostral pons?
- main sensory nucleus of CN5
- motor nucleus of CN5
- mesencephalic nuc. of CN5
- superior and lateral vestibular nuc.
- locus coeruleus
- raphe nuc.
What is the main sensory nucleus of CN5 a continuation of?
spinal trigeminal nuc. of CN5
What muscles does the motor nucleus of CN5 supply?
muscles of mastication
What is the function of the mesencephalic nuc. of CN5?
proprioception of jaw
The locus coeruleus and raphe nuc. both form part of what?
reticular formation
- locus ceruleus= norepinephrine
- raphe nuc=serotonin
MESENCEPHALON=MIDBRAIN
MESENCEPHALON=MIDBRAIN
What are the 3 layers of the midbrain?
- tectum (dorsal layer)
- tegmentum (intermediate layer)
- crus cerebri (ventral layer)
What are the 3 main parts of the tectum?
- superior colliculi
- inferior colliculi
- corpora quadrigemina
The tegmentum is a continuation of the ________________.
pontine tegmentum
The cerebral peduncles are a combination of the ______ and _________.
crus and tegmentum
What does the cerebral aqueduct do?
connects the 3rd and 4th ventricles
The _______________ is located rostral by CN3 and coordinates eye movements.
posterior commisure
levels of inferior colliculus=caudal
- decussation superior cerebellar peduncle
- medial longitudinal fasciculus
- lateral lemniscus
- medial lemniscus
- trigeminothalamic
- spinothalamic
The lateral lemniscus, trigeminothalamic, and spinothalamic all run together in the ______________
medial lemniscus
levels of superior colliculus=rostral
- medial longitudinal fasciculus
- medial lemniscus
- trigeminothalamic
- spinothalamic
The crus cerebri is descending axons from the cerebrum forming the _________ or _________ tracts.
corticospinal, corticobulbar
The most lateral segment of the crus cerebri contains _________, _______ and ________ cortex to pontine nuclei/cerebellum.
parietal, temporal, occipital
The most medial segment of the crus cerebri contains ________ lobe to the pontine nuclei/cerebellum
frontal
The corticospinal tract is located ______ of the lateral segment
medially
The corticobulbar tract is located ________ of the median segment
laterally
What are the 3 parts of the tectum?
- inferior colliculi
- superior colliculi
- pretectal region
The inferior colliculi is your _______ reflex. It has afferent input from the _______, _______ olivary, _______ nuclei via lateral lemniscus. It has efferent output to _______ via brachium of ___________.
- auditory
- cochlear, superior olivary, trapezoid
- thalamus, inferior colliculus
The superior colliculi is your _______ reflex. It has afferent input from the _______. It has efferent output to the _______ spine via _________ for head turning and tracking.
- visual
- retina
- cervical, tectospinal
The tegmentum at the level of the inferior colliculus contains what parts?
- substantia nigra
- periaquiductal gray (PAG)
- trochlear nerve nuclei CN6
- reticular formation
The substantia nigra is part of the _________ for ______ function.
- basal ganglia
- motor
The periaquiductal gray (PAG) is for what functions?
- autonomic regulation
- emotion
- modulation of pain
The trochlear nerve nuclei CN6 functions to do what?
eye movement superior oblique m. (down and medial)
The reticular formation includes the raphe nuclei and does what?
- modulates sensory signaling to cortex
- filters sensory information
- helps with consciousness, sleep/wake
- emotions
- modulates motor signaling
The tegmentum at the level of the superior colliculus contains what parts?
- occulomotor nuc. CN3
- red nucleus
- ventral tegmental area
What are the functions of the occulomotor nuc. CN3?
- somatomotor for eye muscles
- autonomic motor (iris constriction, ciliary muscle for accomodation)
What is the function of the red nucleus?
motor modulation flexor muscles via rubrospinal tract
The ventral tegmental area is part of the __________ motor modulators.
basal ganglia
