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125 Cards in this Set

  • Front
  • Back
How many cuts are there through the brainstem
5
Which one is most caudal
Spinomedullary junction, this where 90 % of pyramidal tract decussates
Which is the next level up
Caudal medulla, this is dorsal column nuclei – internal arcuate fibers
Which is next level up
Rostral medulla, this is important, seen when we cut the cerebellum, it is at 4th ventricle, here we see inferior olivary nucleus and nucleus for CN12
What is the next level up form the rostral medulla
Caudal pons, it is the level of genu of facial nerve 7
What is the next level up
This is the most rostral cut and this rostral midbrain, it is at the level of superior colliculis and CN3
If we get stung by a bee, which tract is going to carry those fibers
Trigeminal ganglion and the cell bodies will be in spinotrigeminal nucleus, the NT would either be glutamate or substance P
What is located in the medulla
CN 9,10,12 motor neuron cell bodies, it also contains autonomic centers for the respiratory, cardiovascular, and GI, it contains the caudal portion of CN5 and 4 of the nuclei of the CN8, it is connected to the cerebellum via inferior cerebellar peduncles
CN12
Hypoglossal, it is purely motor, and it moves the tongue, it’s cell bodies are midline (motor for mid) and the nerve fibers exit between the inferior olive and the corticospinal tract
What happens if there is a lesion in LMN of 12
The tongue points to the side of the lesioned side and it flaccid. Lesion on the left, tongue to the left
What happen if there is a lesion in UMN of 12`
The tongue points away from the lesioned side (i.e. lesion in left hypoglossal UMN, tongue points to the right) and spastic (weak)
CN11 spinal accessory
It is purely motor, it moves head to the opposite side and rotates and elevates the scapula, cell bodies are in upper 5-6 cervical segments of the spinal cord in the spinal accessory nucleus which is located between the dorsal and the ventral horns of the spinal cord (IN THE PICTURE IN NOTES WE ARE LOOKING AT C2 LEVEL)
What happens if there is a lesion in the CN11
Lesion causes a weakness in turning the head to the contralateral side and ipsilateral shoulder drop
What CN are at the level of Medulla and what is their function
9,10 (do the viscera and motor), 12 (tongue muscles)
What is the function ofCN10
Mixed sensory and motor nerve associated with 4 nuclei in the medulla (medial to lateral)
Where do all of the sensory projections go
They go to thalamus
What does VPL receive
It receives input from the body
What VPM receive
It receives the input from the head
What is the function of the anterior solitarius
Taste
What 3 CN do the sensory ear and on what tract do they travel
7,9, and 10(sensory) and they travel on the spinotrigeminal tract, and the fibers in the SG (superior vagal ganglia)
Who does the taste
Nucleus solitarius, and it’s pre-ganglionic cell bodies are in NUCLEUS SOLITARIUS and it’s post ganglionic cell bodies are in IG (inferior vagal nucleus), they do the taste from epiglottis
What is the earliest sign of bells palsy
Outer ear hurts and progresses to on sided complete paralysis
What are the motor function of CN 10
There are no innervations to the somatic skeletal muscles, only skeletal muscle that it innervates are pharyngeal and laryngeal muscles (old gill arches)
What nucleus does the pharynx and larynx
Nucleus ambiguus, it does muscles for swallowing (gag reflex) and phonation (vocal chord) CN10
What nucleus does the innervations to the viscera
Dorsal motor nucleus 10, it does parasympathetic innervations of smooth and cardiac muscles (Ach and muscarinic receptor) CN10
What are the sensory nuclei
They are rostral nucleus solitarius (gustatory) and caudal nucleus solitarius (cardiorespiratory)
What is the function of rostral nucleus solitarius
It does taste from the epiglottis and pharynx and is considered special visceral sensory
What is the function of caudal nucleus solitarius
It does general visceral sensory and it does the aortic arch chemo and baro receptors and it monitors the Bp, PaO2 (not content), and Pco2 and the axons here are covered with myellin
What are the other function of CN10
It does the general somatic sensation from meninges and the external ear via primary sensory neurons in the SG and spinal trigeminal nuclei, 2nd order sensory projection neuron→ VPM→ thalamus
What does a lesion to CNX cause
It causes loss of gag reflex, dysphagia, hoarseness of the voices or still vocal cords, dysartheria
What does a bilateral lesion to CN10 cause
It causes death with complete laryngeal paralysis → aphonia, dyspnea, and aphagia, this is very rare
What is CN9
It mixed sensory and motor, it duplicates 10
What are the motor function of CN9
No somatic skeletal muscle innervations, innervates staphylopharageus via nucleus ambiguus, and elevates the pharynx during talking and swallowing (part of gag with vagus), and it does the PNS innervations of the parotid gland via inferior salivatory nucleus
What are the sensory functions of CN9
Special somatic sensory= taste from the posterior 1/3rd of the tongue (via rostral solitarius gustatory along with vagus) and general carotid body and sinus chemo and baro (via caudal solitarius (cardiorespiratory nucleus with in 10)) and it does general somatic sensation from middle ear, outer ear, pharynx and posterior 1/3rd of the tongue via primary sensory neuron with in the superior glossopharyngeal ganglion, and spinotrigeminal tract, 2nd sensory neuron
What happens if there is a lesion in the CN9
It causes ↓ gag reflex with CNX
What is junction between the spinal cord and brainstem called
It is called spinomedullary motor junction or central canal, this junction represents a cut section
What are the key 5 areas with in this sections
Pyramids, ALS, fasciculus and nucleus gracilis , and cuneatus, spinal trigeminal tract and nucleus
What happens at the level of pyramid at spinomedullary level
This is where the corticospinal tract decussates, these are UMN form M1 motor cortex, these are ipsilateral but here they decussate and become contralateral relative to the neuronal cell body in M1
Key about ALS at spinomedullary level
Spinothalamic, spinoreticular, and spinomesencephalic tracts that do sensory projection neurons encoding pain, itch and temp from the contralateral body
Key about gracilis at the spinomedullary level
Sensory, primary afferent, does proprioception, fine touch, and vibration below T6 (legs, medial), the axons will cross over at the internal arcuate fibers and make up the medial lemniscus, ipsi
Key about cuneatus at spinomedullary level
Sensory, primary afferent, does proprioception, fine touch, and vibration aboveT6 (upper body, lateral), the axons will cross over at the internal arcuate fibers and make up the medial lemniscus, at this level it is ipsi
Key about spinal trigeminal tract at spinomedullary level
Primary sensory afferents from the ipsilateral face, pain, temp, itch, and crude touch to the face, mouth, anterior 2/3rd of the tongue, nasal sinuses, suprtentorial dura (CN5) as well as encoding pain and temp from the outer ear canal on CN 7, 9, and 10. Spinal trigeminal nucleus sends axons w/c cross the midline and to travel to trigeminothalamic tract and synapse in the VPM
When we say caudal medulla what are we looking at
Internal arcuate fibers i.e. central canal
Key about the pyramid At the caudal medulla level
Corticospinal tract motor neurons from ipsi M1 cortex
ALS At the caudal medulla level
SPNTHLMIC, SPINRTCULR, AND SPINMSNCPHLIC tracts, sensory projection neurons encoding pain, itch and temp from the contralateral body
Gracilis At the caudal medulla level
Primary afferents for touch, proprioception and vibration below T6, cross over as internal arcuate fibers and become medial lemniscus
Cuneatus At the caudal medulla level
Primary afferents for touch, proprioception and vibration above T6, cross over as internal arcuate fibers and become medial lemniscus
Medial lemniscus At the caudal medulla level
Sensory projection encoding proprioception, fine touch, and vibration from the contralateral body
Spinotrigeminal tract and the nucleus At the caudal medulla level
Primary sensory afferents from the face, pain, temp, itch, and crude touch to the face, mouth, anterior 2/3rd of the tongue, nasal sinuses, suprtentorial dura (CN5) as well as encoding pain and temp from the outer ear canal on CN 7, 9, and 10.
Which side is the damage on if it occurs at gracilis or cuneatus nucleus and tract level (at caudal medulla)
It is ipsilateral and remember both of these go to VPL
What if it happens at the medial lemniscus
It is contralateral
What is a land mark for a section through the rostral medulla
4th ventricle
What is the most common place for a stroke to take place
Rostral medulla is the most common place for a stroke to occur
Pyramids at the rostral medulla
Corticospinal tract motor neurons from M1 (ipsi)
ALS at the rostral medulla
SPNTHLMIC, SPINRTCULR, AND SPINMSNCPHLIC tracts, sensory projection neurons encoding pain, itch and temp from the contralateral body
Medial lemniscus at the rostral medulla
Sensory projection encoding proprioception, fine touch, and vibration from the contralateral body
Spinotrigeminal tract at the rostral medulla
Primary sensory afferents from the face, pain, temp, itch, and crude touch to the face, mouth, anterior 2/3rd of the tongue, nasal sinuses, suprtentorial dura (CN5) as well as encoding pain and temp from the outer ear canal on CN 7, 9, and 10.
What is not seen at this level and what do we call it
Gracilis and cuneatus nuclei and fascicule, at this point we call it medial lemniscus
Vestibular nuclei at the rostral medulla
CN8 vestibular portion and it is from ipsilateral vestibular membranous labyrinth
Solitary nucleus and tract at the rostral medulla
We see sensory fibers from tongue encoding taste (CN7,9, and 10), along with cardiorespiratory information from the carotid artery, and aortic arch (CN9,10)
Hypoglossal nucleus at the rostral medulla
LMN for ipsilateral half of the tongue
Ambiguus nucleus at the rostral medulla
LMN, muscle in pharynx and larynx (CN9 and 10), muscarinic receptors, ANS
Dorsal motor nucleus of 10 at the rostral medulla
Motor preganglionic fibers to the viscera in the thorax and the abdomen (CN10) + this and ↓ HR
Inferior olivary nucleus at the rostral medulla
Give rise to the climbing fibers that innervate the contralateral ½ of the cerebellum
Inferior cerebral peduncles at the rostral medulla
ICP have cerebellar afferents (including crossed olivocerebellar fibers which become climbing fibers in the cerebellar cortex)
Lesions in the brainstem have what kind of deficits
Ipsilateral head and contralateral body
If we damage the hypoglossal nerve or the nucleus on the right, which way does the tongue point
Tongue points to the ipsilateral side i.e. to the right
What if there is damage at T1-L3 and ALS
Ipsilateral Horner’s, and contralateral loss of pain, temp, and itch
What is known as the vomiting center
Area pastrema
What do the inferior olivary nuclei join with
They join with the fibers that go to the cerebellar peduncles
What are the key features associated with PONS
5,6,7,8, 4th ventricle on the dorsal surface of the PONS also large thick middle cerebellar peduncles with 23 million pontine nuclei
What tracts are found at the base of the PONS
Corticospinal, corticopontine, and corticobulbar
Corticospinal at the pons
These are UMN and go thru the cerebral peduncles and go all the way down to the spinal cord and 90% decussate and synapse on LMN w/c then synapse on the skeletal muscles
Corticopontine at the PONS
It is shorter than the CS and starts from the cortex and goes to the PONS, the fibers from here eventually go to cerebellar peduncles
Corticonuclear also called ________ at the PONS
Corticobulbar,
Face has what kind of innervations and what is the exception
Bilateral and CN7 is the only exception and it has contralateral for LMN
Where are the nerve bodies for CN11 located
Spinal cord
Where is the lateral lemniscus located and what does it do
It is the auditory pathway and it is located at the level of pons, this tract carries a bulk of ascending auditory pathway from both cochlear nuclei to the inferior colliculus of the midbrain
What does vestibulocochlear nucleus
It does auditory and balance
CN7 motor
Located at pons, mixed nerve, motor ↑and sensory↓, the nucleus is just ventrolateral to abducens nucleus and it’s fibers curve around the abducens nucleus, it has branchial motor control to the muscles of the facial expression, stapedius muscle, and part of the digastrics muscles, as far PNS input is concerned it innervates the lacrimal gland and salivary glands except parotid which is done by glossopharyngeal nerve
CN7 sensory (at pons)
Visceral sensory to the anterior 2/3rd of the tongue(taste),somatic sensory from the external ear
What happens if there is a lesion of the nucleus or nerve
Bell’s palsy, ipsi full face paralysis, corner of the mouth droops, cant close the eyelids, red and dry eyes, cant wrinkle forehead, hyperacusis (sounds are loud), ↓ blink reflex, ↓ taste (ageusia), pain in outer ear, this would be a lesion in the LMN
What if there was supranuclear lesion
This would be a UMN lesion and it would cause problem in inferior contralateral face
Central 7
Central facial paralysis
CN6 abducens at PONS
Motor nerve and the center for horizontal gaze, located near the midline lateral to MLF and below the 4th ventricle, it supplies the LR and interneuron to CN3 via MLF, , keeps the 2 eyes yoked together, and it is driven by PPRF which is the center for horizontal eye movements, and it allowed for the inputs from the cortex and vestibular nuclei to provide smooth horizontal control of conjugate eye movement
What happens with the lesion of CN6 nucleus
Diplopia ipsi, (CN6 palsy), lateral gaze palsy (ipsi)
What happens with the lesion of CN6 nucleus along with a lesion in ipsi MLF
It will cause ipsi lateral gaze palsy and INO
What would happen if there is a lesion in cerebral hemisphere
Gaze to the side of the lesion
CN5 at pons
Mixed, sensory↑ and motor↓
Where is the nucleus to motor Cn5 located and what are the characteristics
It is located in upper to mid pons, and it does muscles of mastication and tensor tympani muscle
Where are the CN5 sensory nucleus located and what are it’s function
Nuclei run from midbrain to the upper cervical spinal cord, it does sensory to the face and it does proprioception via MSNCPHALIC TRIGEMIAL NUCLEUS, it does fine touch and dental pressure via CHIEF OR TRIGEMINAL SENSORY NUCLEUS, and crude touch, pain and temperature via SPNL TRGMNAL NUCLEUS
What do we see at the level of caudal pons
We see genu of the facial nerve
What do we see at the base of PONS
Corticospinal, corticobulbar, and corticopontine motor neurons axons from the ipsi M1 cortex
What is going on in ALS at caudal pons
Spinothalamic tract, sensory projection neurons that do pain, temp and itch from contralateral
Medial lemniscus at caudal pons
Sensory, proprioception, fine touch, and vibration contralateral
Abducens at caudal pons
LMN innervating the ipsi lateral rectus muscles
Facial nerve at caudal pons
Internal genu of facial N, this at facial colliculis, here the fibers from CN7 wrap around the CN6. This where facial nucleus is and these are LMN that innervating muscles of the face and closing the eye lids via orbicularis occuli muscle
Spinotrigeminal tract at caudal of pons
This is the tract and the nucleus, sensory neurons from ipsi face provide pain, temp, itch, and crude sensation for the face, mouth ant 2/3r of the tongue, nasal sinuses, supratentorial dura CN5 as well as pain and temp from the outer ear on CN7,9,10
Vestibular nuclei caudal pons
Sensory from the vestibular portion of the membranous labyrinth encoding acceleration
MLF at caudal pons
Motor tract involved in eye movement coordination
What CN are located at the Midbrain
CN3 and 4, and inferior and superior colliculi which overlie the cerebral aqueduct
What does inferior colliculi process
Auditory information that they receive bilaterally from cochlear nuclei and from the lateral lemniscus
What does superior colliculi process
It processes and coordinates eye movements
What is the area in the midbrain that is associated with pupillary light reflex
This is the pretectal area and it vertical and vergence movements of the eye
What else is located in the midbrain that is problematic in PD patients
Substantia nigra, and it is the largest nucleus in the midbrain, and is the source of dopamine and GABA
What are the function of CN4 at midbrain
it is motor, does superior oblique, causes Intorsion or depression of the eye ball
What do u see with a lesion in CN4
Diplopia, weakness while looking down with the abducted eye
Who does the extorsion of the eye
This is inferior oblique and it is the CN3
What is the function of CN3 at the level of midbrain
Motor (somatic and PNS), it inferior oblique, inferior, superior, and medial recti muscle
What does the motor component of CN3 do
does the levator palpaberae and open the eye lid
What does the PNS component of CN3 do
Does the pupillary light reflex via sphincter papillae muscles it contracts the muscles of iris and constricts the pupil miosis compared to mydriasis which dilates the muscles and works through the SNS. It also does the ciliary muscles w/c upon contraction cause the lens to ↑ it’s curvature
What happens if there is a lesion in CN3
If the lesion is in PNS component then it cause the loss of near vision and Ptosis (eye lid drooping due to loss of levator palpaberae) and loss of light reflex, the eye ball is down and out at rest and you have to manually lift the eyelid to do this because patient cant, if the lesion happens in the SNS component then→ to Horner’s syndrome
What do we see at the rostral midbrain
Cerebral aqueduct,
Cerebral peduncles
Location of descending corticospinal, corticobulbar, and corticopontine fibers from the ipsi cortex
ALs at rostral midbrain
Sensory, spinothalamic tract, pain afferents from contralateral body
Medial lemniscus at rostral midbrain
Proprioception, touch, vibration from contralateral body
Mesencephalic trigeminal nucleus at rostral midbrain
Sensory proprioception from the muscles of mastication, tongue and extraocular muscles CN5
PAG at rostral midbrain
Periaqueductal grey pain control fibers, descending
Red nucleus at rostral midbrain
Motor nucleus projects to alpha motor neurons (spinal)
Substantia nigra at rostral midbrain
Pars compacta, dopaminergic, part of motor control by basal ganglia and the axons terminate in putamen and caudate
CN3 at rostral midbrain
Does all of the extraocular eye muscles except for LR and SO, it also keeps the eye lids open, and also the SNS portion of it also keeps the eyelids open via muller smooth muscles, it also has the edinger westphal nucleus and it does the PNS innervations of ciliary muscles of the lens and it also does the pupillary constrictor muscles and also keeps the eye lid open
MLF at rostral midbrain
Motor pathway coordinating eye movements
Medial geniculate nucleus at rostral midbrain
Auditory pathway to primary cortex
Lateral geniculate nucleus at rostral midbrain
Visual pathway to the primary cortex
What is required for jaw jerk reflex
CN5 sensory and motor