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Thomadaki Neur 1

NYCC demyelinating disorders to cranial nerves at brainstem + levels

QuestionAnswer
Interference with _______ transmission results in diseases of the central and peripheral nervous system synaptic
most common demyelinating disease of CNS Multiple Sclerosis
Multiple Sclerosis is a disorder of the CNS
MS is a _____________ disease of the CNS demyelinating
MS has the presence of multifocal ________ plaques
a plaque in the CNS is scar tissue deposited at sites of demyelination
the presence of __________indicates an autoimmune disease Antibodies
Antibody presence indicates an autoimmune disease
mean age of MS onset 33
which gender is more affected by MS women
MS is characterized by spontaneous remissions and relapses at irregular intervals
An adjective to describe MS might be unpredictable, irregular, spontaneous
45-75% of patients with _________ ___________ develop MS within 15 years optic neuritis
optic neuritis is the inflammation of the optic nerve
how does MS work? cells attack myelin sheaths, resulting in scar tissue in the CNS
the body attacks its own ________ made by ___________ in the CNS = Multiple Sclerosis (multiple plaques) myelin, oligodendrocytes
MS affects all systems but prefers sensory (cerebellar) system
parasthesia is a symptom of MS
visual disturbances are symptoms of MS
internuclear ophthalmo-plegia is a symptom of MS where one eye does not follow the other
extremity incoordination and clumsiness are symptoms of MS (cerebellar)
paresis with ________ is a symptom of MS spasticity (CNS-Upper Motor Neuron is spastic paralysis)
paresis means weak
what are the subcategories of spasticity hypereflexia, hypertonia (UMN symptoms)
what exacerbates symptoms of MS? temperature
name the 5 symptoms with descriptors of Multiple Sclerosis 1. paresthesias 2. visual disturbances 3. internuclear opthalmo-plegia (one eye doesn't follow the other) 4. extremity incoordination and clumsiness 5. paresis with spasticity (hypereflexia, hypertonia)
Paresthesias, visual disturbances, internuclear opthalmo-plegia, extremity incoordination and clumsiness, paresis with spasticity (hyperflexia, hypertonia) and exacerbation of these symptoms by heat are all signs of multiple sclerosis of the CNS (UMN disease of primarily cerebellar function that is unpredictable with scarring as plaques where myelin has been destroyed in the brain)
most common immune system disease vitiligo
most commone CNS demyelinating disease MS
With Vitligo (the most common immune sys disease), the body attacks its own melanin, causing white patches of skin (Harry)
is vitiligo dangerous? no, it is benign
what disease involves the body attacking its own melanin, leaving white colorless patches? vitiligo
Does vitiligo affect anything besides skin? yes, hair, eyebrows, eyelashes
what is the culprit if vitiligo? T-cells (immune cells)
T-cells are the culprit in vitiligo
in ________, the immune system decides cell nuclei (oh crap!) are bad and goes about killing them lupus
MS is an _______motor neuron disease. Upper (CNS)
If, as in MS, certain areas are demyelinated preferentially, the plaqua or scar formation prevents what from happening? action potentials
no myelin, no action potentials
there are 4 phases of MS benign, mild, progressive, severe
cutting an UMN results in ________ paralysis spastic (hypereflexia, hypertonia)
cutting an LMN results in ________paralysis flaccid (dead)
"glove and stocking" pattern of sensory loss or paresthesia Guillain-Barre syndrome
Guillain-Barre syndrome affects upper or lower motor nerves? LMN (starts at hands and feet/glove and stocking)
If G-B syndrome is LMN, what nervous system division? PNS
G-B syndrome is acute, demyelinating _________ _________ peripheral neuropathy
acute demyelinating peripheral neuropathy is characteristic of Guillain-Barre syndrome of PNS/Lower Motor Neuron
G-B syndrome usually follows a _________ infection (but could be any kind of infection) respiratory
Guillain-Barre syndrome is an __________ disease of acute demyelinating peripheral __________. autoimmune, neuropathy
glove and stocking pattern of sensory loss or paresthesia G-B syndrome
paresis with HYPOreflexia and atrophy G-B syndrome
paresis with HYPOreflexia and atrophy are symptoms of G-B syndrome, a ______ LMN of PNS problem
Is G-B syndrome life-threatening? can be, even though a remission is possible
Demyelinating periphery = lower motor neuron/flaccid paralysis
with G-B syndrome, the sensory + motor paresthesia runs from distal to proximal (hands and feet towards center, hence "glove and stocking parethesia")
Autoimmune disease involving BOTH upper and lower motor neurons because involves BOTH CNS and PNS Amytrophic Lateral Sclerosis (plaques) or ALS
ALS is also called Lou Gerhig's disease
what disease is unique to motor neurons? ALS
there is no other known disease affecting both LMN's and UMN's except ALS
what kind of paralysis do victims of ALS have? spastic (UMN) and flaccid (LMN)
a disease of middle and late life (rarely seen in patients under 30) ALS
why is ALS so hard to diagnose? NO sensory or autonomic symptoms with ALS
what is often the first manifestation of ALS? hand weakness "I keep dropping things"
ALS hand weakness (1st sign) is accompanied by atrophy and general HYPERreflexia (spastic part) which progresses rapidly
90% of ALS patients die within 6 years due to respiratory insufficiency
famous ALS sufferer who is still living Stephen Hawking
a lower motor neuron disease of the muscular junction myasthenia gravis
myasthenia gravis is an autoimmune disease of the neuromuscular junction
myasthenia gravis is characterized by fluctuating weakness of skeletal muscle and fatigue
what causes myasthenia gravis? destruction of Nicotinc AcH at neuromuscular junction
why would adding an acetylcholine esterase inhibitor be handy for myasthenia gravis because it would slow the destruction of nicotinic AcH at the neuromuscular jcn, and the person would not tire so easily
what physiology characterizes myasthenia gravis presence of ANTIBODIES against nicotinic acetylcholine RECEPTORS (in 90% of the patients, the number of receptors is compromised)
what is another reason, besides antibodies for ones own nicotinic AcH receptors, that makes AcH unavailable at neuromuscular jcn in myasthenia gravis normal infolding of the postsynaptic membrane is reduced and the cleft is, therefore, enlarged so less NT's find their receptors before they get degraded by acetylcholine esterase.
does mysathenia gravis kill AcH? no, it kills the receptor so the nicotinic AcH is out there, but has no where to go! and all the available receptors (very few) are occupied.
where do nicotinic AcH receptors live? in skeletal muscle
so what happens in mysasthenia gravis patients whose antibodies kill Nicotinic AcH receptors in skeletal muscle? they get fatigued easily, weak
what kind of nervous system disease is myasthenia gravis PNS only at neuromuscular junctions
symptoms of myasthenia gravis - think week, fatigued muscles ptosis (droopy eyelids), affects eye/facial/phonic muscles (dysphonia), swallowing weak (dysphagia), trunk and extremity weakness maybe later in disease, 15% of patients have a thymoma
ptosis drooping eyelids - symptom of myasthenia gravis
eye/face/phonic weakness symptom of myasthenia gravis
phonic weakness is called dysphonia
swallowing weakness dysphagia (symptom of myasthenia gravis)
trunk and extremity weakness that may come later myasthenia gravis
15% of myasthenia gravis patients have a thymoma
like multiple scerosis, myasthenia gravis is unpredictable with spontaneous remissions
what do MS and MG have in common? both unpredictable with spontaneous remissions (MS is spasticity and balance/UMN while MG is weakness and thymoma/LMN)
in severe cases, respiratory failure can result myasthenia gravis (LMN flaccidity)
what is usually perscribed to help myasthenia gravis suffering? NEOstigmine (an acetylcholinesterase inhibitor)
what operation is often perfomed on myasthenia gravis sufferers? thymectomy; it works!
why won't myasthenia gravis patients die of heart failure? because the heart works on muscarinic Ach -it doesn't have nicotinc receptors (only skeletal muscle has N-AcH receptors)
a lesion to the medial lemniscus would result in what happening to fasiculus gracilis?a. chromatolyticb. Wallerianc. anterograded. retrograde d. retrograde
transneuronal retrograde degeneration happens to the neuron that provided the injured cell with input (1*, 2*, or 3* afferent in pathway - whichever entire one is before lesioned nerve)
chromatolytic reaction happens to the proximal part of axon and cell body of a lesion - likely to die of apoptosis but if not, then chromatolytic changes happen
what are chromatolytic changes that happen only to proximal cell body and axon in a lesion eccentric nucleus, Nissl substance (RER) fragments, increase of RNA and protein synthesis, gene expression changes
what happens to lesioned neuron in Wallerian degeneration? Wallerian is the distal segment of lesioned axon and it degenerates, myelin sheath fragments, debris is gobbled up by microglia
transneuronal Anterograde degeneration the postsynaptic neuron (1*, 2*, or 3* afferent in path -whichever would have been synapsed to next) atrophies and eventually dies from lack of stimulation (like a desk job neuron)
order of degenerations upon axotomy (axontmesis) retrograde (1*), chromatolytic (Proximal part of axon and cell body of 2*), Wallerian (distal part of cut axon of 2*), anterograde (last neuron in three neuron chain which dies of lack of stimulation 3*)
injury to an axon divides it into a proximal portion of cell body and injured axon (chromatolytic) and a distal cut free axon (Wallerian)
another term for transneuronal degeneration (either retrograde or anterograde) synaptic stripping
how could axons of the PNS regenerate? COLLATERAL SPROUTING via Schwann Cells of PNS releasing chemotropic (growth) factors to guide the axon fragments
the _______ portion of an injured axon (chromatolytic) grows axonal sprouts that are guided to the _______ (Wallerian)portion by chemotropic factors secreted by Schwann cells prosimal (chromatolytic), distal (Wallerian)
Frey's syndrome when axons are guided to wrong targets (fried! syndrome) - wouldn't want that in CNS!
if axonal sprouts don't reach their distal element (Wallerian), they become entangled and form a benign mass = Neuroma
in the embryo, both the CNS and PNS nerves promote axonal growth; only the ______ retains this ability PNS
3 reasons CNS neurons don't regenerate: Schwann cells are only in PNS, CNS has growth inhibiting factors (ie, central myelin), CNS cells make regeneration-inhibiting proteins after they are done growing
3 reasons CNS neurons don't regenerat: (short) Schwann's, Inhibitors, non-regeneration
with CNS injury, what do we see scarring (plaques), astrocyte numbers high, microglia recruitment, inflammation
if the surrounding tissues in the CNS are selectively excluded, healing is likely and enhancedd
Introduction of trophic substances (growth), Schwann cell grafts, antibodies against inhibitors, transplant fetal tissue, immunosuppressants, anti-inflammatory steroids are all ways to encourage axonal regeneration
Functions of the spinal cord (3) relay for incoming sensory, conduit for ascending and descending, origin of LMN's and therefore commands the skeletal muscles
functions of spinal cord (3) relay, conduit, commander (RCC)
the origin of lower motor neurons is also called the Final Common Pathway of SHERRINGTON (Commander Sherrington)
Bell-Magendie Law sensory info goes IN to the spinal cord via DORSAL roots of spinal nerves and motor "commands of Sherrington" leave the spinal cord via VENTRAL roots of spinal nerves
Bell-Magendie means dorsal afferent in, ventral efferent out or SENSORY IN, MOTOR OUT
sensory in, motor out is the Bell-Magendie law
upper motor neurons start in the cortex -higher centers
UMN send commands to lower motor neurons
lesions of upper motor neuron = spastic paralysis
lower motor neurons start in the ventral horn cells of spinal cord and cranial nerve nuclei of brainstem
where do LMS's start ventral horn cells (cord) & motor cranial nerve nuclei (stem)
LMS' directly command what skeletal muscles to contract, via spinal and cranial nerves
Lesion of LMN = flaccid paralysis (no motor, no flex, no move)
areflexia flaccid paralysis/LMN
hyporeflexia flaccid paralysis/LMN
Grey cell columns 1-6 1-pericornual cells, 2-substantia gelatinosa, 3-nucleus proprius, 4-Nucleus Dorsalis (I am the Dor, #4), 5-Interomediolateral cell column, 6-motor nuclei (two)
pericornual cells #1 relay center for pain and temperature
substantia gelatinosa #2 "substantiates" pain - editor
Nucleus Proprius #3 contains cell bodies of several tracts, like spinothalamic tract for pain & temp
Nucleus Dorsalis #4 "I am the Dor, I can feel Clarke's feet on the floor" c8-L3 only -involved in ProPRioreCEption of lower body
INtermediolateral cell column #5 T1-L2 preganglionic SYMPATHETIC, S2-S4 preganglionic PARAsympathetic
MOTOR nuclei #6's (two) Ventral Horn Cells: cell bodies of LOWER MOTOR NEURONS both alpha and gamma that innervate SKELETAL muscle
Substantia gelatinosa #2 modifies pain via interneurons (buffer of lawyers who decide if pain is 'substantiative' enough)
Dorsal root afferents influence motor neurons of ventral horn cells how? spinal reflexes and several descending tracts for control of motor activity of brain (ie, cuneo-cerebellar and spino-cerebellar)
apart from #4 - I am the Dor, I can feel Clarke's feet on the floor, what does Nucleus Dorsalis do? Gives rise to SPINO-CEREBELLAR TRACT
nucleus dorsalis is the spinocerebellar tract
Intermediolateral cell columns have preganglionic sympathetic (T1-L2) and preganglionic parasympathetic (S2-S3) neurons.
what are the levels of nucleus dorsalis/I am the Dor/spinocerebellar? C8-L3
in the dorsal horn, the lateral division of the rootlet enters the ______ first, and divides to both ascend and descend. DLF (Dear Little Friend) for lateral rootlet of dorsal root ganglion
the DLF is where? at the very beginning of the dorsal horn
the lateral rootlet enters DLF, ascends and descends. Most afferents entering the dorsal horn terminate where? at their own segment or 2 segments up
TRACT CELLS give rise to spinothalamic fibers
where are most of the tract cells in the DORSAL horn (sensory) Nucleus Proprius #3 in the dorsal horn layer
why would lateral afferent rootlets terminate in the Nucleus PRoprius? Because the Nucleus PRoprius has A & C PAIN fibers! ouch!
Why would the lateral afferents from ventral rootlets in the nucleus proprius? because A&C PAIN fibers (spinothalamic tract) are here
What is conveniently before the Nucleus Proprius #3? the Substantia Gelatinosa (buffer of lawyers seeing if pain claim can be substantiated- editors)
substantia gelatinosa #2 pain modifier
now that we know why lateral rootlets from the afferent dorsal root ganglion would stop in the nucleus proprius, tell me the Pain & Temperature pathway: 1* Sensory Afferent proximal axon to lateral rootlet-CLIMB 2 LEVELS UP!!!!-enter DLF-enter Substantia Gelatinosa for editing-enter Nucleus Proprius with it's A&C pain fibers-synapse! 2* cross contralateral to LATERAL SPINOTHALAMIC TRACT-ascend to thalamus
unmyelinated and slow, the contralateral _______________ is always the last to know! Lateral Spinothalamic Tract (LST)
Besides going UP TWO LEVELS to synapsing with 2* afferents in Nucleus Proprius, then crossing to Lateral Spinothalamic tract to run with A&C pain fibers, what could the entering lateral rootlets do? not synapse but ascend directly
what is the trick to remembering the Pain & Temperature tract? the dorsal root sensory afferents go UP TWO LEVELS before they synapse in Nucleus PRoprius, then cross over to Lateral Spinothalamic Tract
Where are the cell bodies of the Dorsolateral Fasiculus? (DLF) in the dorsal root ganglion
the DLF is _______ to the stimulus of Pain & Temp. Ipsilateral
where does the DLF end? in the Ipsilateral Nucleus Proprius, 2 levels above where it entered the spinal cord
what happens to the neuronal cell body of an A or C fiber when it enters the spinal cord? It mostly ends 2 doors up in the Nucleus PRoprius (so it can synapse and the 2* can cross to Lateral SpinoThalamic tract for Pain & TEmperature)
What does the lateral spinothalamic tract contain? *2 afferents for pain and temperature
where are the cell bodies of the *2afferents for pain and temperature of the lateral spinothalamic tract? in the nucleus proprius, back where they synapsed with primary afferent
what do 2*secondary afferents from nucleus proprius cross to get into the lateral spinothalamic tract? Ventral White Commissure
If something crosses the VWC, what, in essence, has it done? it has become contralateral
where does the secondary 2*afferent from nucleus proprius that crossed VWC to joint Lateral spinothalamic tract take its pain and temperature message? to the thalamus
another term for SPINOTHALAMIC pathway ANTEROLATERAL system
Does pain & temperature take the same lateral spinothalamic tract all the way from when it crosses the VWC to the thalamus? yes, it has already crossed once so it won't cross again.
The anterolateral system has both the lateral spinothalamic tract (LST)for Pain & Temperature and the ventral spinothalamic tract for Light Touch
the light touch pathway is called the Ventral spinothalamic tract
the Ventral Spinothalamic tract contains 2* afferents that are __________to the sensation Contralateral (remember, it already crossed after synapsing in Nucleus Proprius)
The VST or Light Touch Pathway ends in the thalamus
the Lateral Spinothalamic tract (pain & temp) and the Ventral Spinothalamic tract (light touch) often run together - they are called (2) The VentroLateral system or Anterolateral sys
what are structures that carry a specific type of information from lower center (peripheral body) to higher centers? ascending pathways
ascending pathways usually consist of a chain of ________ tracts
the first neuron in the pathway is the primary (1*) afferent or _______- ________ neuron, etc. first order, second order, third order
deep sensibility pathway includes the modalities of: crude touch, vibration sense, conscious proprioception, discrimnatory touch (fine touch), stereognosis
crude touch and vibration can please desperate sistahs deep sensibility pathway: crude touch, vibration, conscious proprioreception discriminating stereognosis
what part of the Deep Sensibility pathway carries first order neurons? Dorsal columns (fasiculus gracilis and fasiculus cuneatus)
what is another name for fasiculus gracilis and cuneatus together? (deep sense path) Dorsal Funiculus or dorsal columns - crude touch and vibration can please desperate sistahs
Dorsal columns (dorsal funiculus) carry 1* first order ________ (afferent or efferent) afferents
is fasciulus gracilis lateral or medial medial (lower half from T6 down)
Fasiculus Gracilis carries first order afferents from the __________ lower body IPSIlateral
where do first order 1* afferents from Fasiculus Gracilis end? Nucleus Gracilis in the medulla
the inside of the structure where F.Gracilis 1*afferents synapse is called Nucleus Gracilis. What is the outside, visible structure called? Gracile Tubercle
Inside the gracile tubercle is the nucleus gracilis, where 1* first order afferents from the dorsal column of fasiculus gracilis terminate (medulla)
the gracile tubercle is on the dorsal surface of the upper medulla
Fasiculus Gracilis does NOT carry any __________ from the lower body proprioception
What DOES carry propriocepton from the lower body, because Fasiculus Gracilis does not. Spino-cerebellar tract is for proprioreception from lower body
Fasiculus Gracilis does not carry proprioreception from lower body. What DOES it carry? everything else from deep sense: crude touch and vibration, discriminatory (fine) touch, stereognosis
at what levels does Fasiculus Gracilis exist? ALL levels.
What dorsal column is present for deep sense from the upper body and at what levels? Fasiculus CUNEATUS, T6 and up!
what uses the Great Pyramidal Decussation? What uses the Medial Lemniscus to cross? GPDecussation is used by descending motor of corticospinals from pyramids to decussation to motor tracts in white matter. Medial Lemniscus is used by deep sensibility Dorsal Columns ascending pathway from F. Gracilis and Cuneatus-tubercles-ML-thalamus
Fasiculus Cuneatus primary afferents from the dorsal root ganglia sensory neurons are responsible for deep sensiblity (including Proprioception) from C1-T6.
How do spinal nerves exit, above or below, in the cervicals? above- that's why there are 8.
How do spinal nerves exit, above or below, in the thoracic and lumbar areas? below - T1 exits below and so on
Where does Fasiculus Cuneatus end? Cuneate tubercle (outside) Cuneate NUCLEUS inside at medulla
the fasiculus cuneatus exists from T6 and above
what two columns are involved in the deep sense path? fasiculus gracilis (T6down) and fasiculus cuneatus (T6above)
describe deep sensibility path for fasiculus cuneatus dorsal root ganglion central axon enters white matter of fasiculus cuneatus anywhere above T6, carries all deep senses (CT,V,CP,DT,S) to CUNEATE NUCLEUS. Synapse! 2*second order crosses via arcute fibers to MEDIAL LEMNISCUS. Ascends to Thalamus.
describe deep sensibility path for fasiculus GRACILIS enters F.Gracilis column but NO PRopriO! Ascends to level of inferior olivary nucleus in medulla and synapses! 2* crosses via arcuate fibers to Medial Lemniscus, ascends to thalamus. Synapses!
somatotopy the organization of tracts, nuclei, and brain areas reflecting the body's organization. Correspondence is known as somatotopy
spinal cord shape at lumbar? thoracic? cervical? lumbar is round, thoracic is egg/oval, cervical is football/oblong
since fasiculus gracilis does NOT carry proprioreception for lower body, who does? SPINO-CEREBELLAR tract is the proprioreception pathway for lower body
spino-cerebellar tracts carry proprioreception info from lower body to ____________ cerebellum Ipsilateral cerebellum
lesion of the spino-cerebellar tract (via the cerebellar peduncles) causes Ataxia
ataxia unsteady, wide gait
unsteady, wide gate is called ________ and is caused by a lesion to the _________________ tract. ataxia, spino-cerebellar tract
Pain and Temperature pathway is also called the anterolateral system or VENTRO-LATERAL system
where is the dorsolateral fasiculus located? between the central median fissure and the dorsolateral funiculus (bird's eye view)
the dorsolateral fasiculus for pain and temperature is divided into the LATERAL spinothalamic tract and VENTRAL spinothalamic tract
pain and tem go from the nucleus proprius to the lateral spinothalamic tract
fine touch goes from the nucleus proprius to the ventral spinothalamic tract
the dorsolateral fasiculus (Dear Little Friend)contains 1* pain and temperature afferents
the cell bodies of the first order pain and temperature neurons are in the dorsal root ganglion (sensory)
the DLF is _________ to the stimulus ipsilateral (doesn't synapse P&T until nucleus proprius)
the DLF ends in the ipsilateral nucleus proprius, 2 levels above where it entered the spinal cord
2* second order neuron cell bodies for pain & temperature are located in the Nucleus Proprius (the appropriator!)
2* axons from the nucleus proprius cross the Ventral White Commissure to reach the Lateral SpinoTHalamic tract and ascend with their pain and temp message to the thalamus
Does the Pain and temp path cross again after VWC? no, one cross so any lesion before the nucleus proprius is ipsilateral loss of Pain & Temperature 2 doors down from where it entered DLF and anything at Nucleus Proprius or afterward is Contralateral P&T Loss from 2 doors down where it entered DLF.
When does the Lateral spinothalmic tract for Pain and Temperature become contralateral loss (to the lesion) 2 doors down? after it synapses in nucleus proprius with axons that travel across VWC to Lateral spinothalamic tract. Anything at or after 2* second order neuron is contralateral 2 doors down.
what is pain and temp trick? 2 doors down. Ipsi- or Contralateral loss at L4 and down if lesion is at L2, etc.
what is the trick with a lesion to the nucleus proprius at C7? would be contralateral loss from T1 down because there is a C8 nerve to count!
what pathway is responsible for light touch Ventral spinothalamic tract
the ventral spinothalamic tracts for light touch sits ventral to the lateral spinothalamic tract for pain and temperature from 2 doors down
the ventral spinothalamic tract for light touch contains 2* second order afferents contralateral to the sensation
why would both ventral and lateral spinothalamic tracts contain 2* second order afferents CONTRALATERAL to the sensation, ergo the lesion? because they have both synapsed, become second order neurons, and crossed the VWC to their tracts
a cross means contralateral
no cross means ipsilateral
together the lateral and ventral spinothalamic tracts (pain and temperature lateral, light touch ventral) are called Ventro(antero)-Lateral system
what are the important white matter descending pathways? (2) Lateral Corticospinal Tract and Ventral Corticospinal Tract
both the Lateral Corticospinal tract and the Ventral Corticospinal Tract are part of the CORTICOSPINAL TRACT (Pyramidal Tract)
Both LCST and VCST contain ________'s mostly involved in voluntary movement UMN's (upper motor neurons)
why would the lateral corticospinal and ventral corticospinal tracts contain UMN's for voluntary movement, instead of LMN's? because they are still within the CNS and have not exited the spinal cord, ergo UPPER motor neurons
where do corticospinal fibers begin? in the Cortex ("cortico-) of motor, sensory or other areas
the corticospinal fibers proceed through the corona radiata, internal capsule, crus cerebri (midbrain), basilar pons, and through the medullary pyramids (anterior/ventral is motor and the pyramids are ventral)
path of corticospinal fibers from cortex to spine for UMN skeletal movement: corona radiata, internal capsule, crus cerebri, basilar pons, medullary pyramids
where do the corticospinal fibers decussate? at the Pyramidal Decussation of Medulla
At the lower medulla, what percentage of Lateral Corticospinal Fibers decussate at the pyramidal decussation? 85%
85% of fibers from motor cortex cross the decussation and become Lateral Corticospinal tract fibers
What does the 85% of decussated Lateral Corticospinal tract fibers affect? Ipsilateral muscles
how does the 85% of decussated Lateral Corticospinal Tract fibers affect the ipsilateral muscles? by synapsing onto LMN's (lower motor neurons) in the Ventral horn OR onto Interneurons and then synapsing onto the Ventral HOrns.
Whether the descending 85% of Lateral Corticospinal Tract fibers from the motor cortex synapses directly onto an LMN or via an interneuron and then an LMN, where do they wind up? in the ventral horns, synapsing on an LMN to effect distal skeletal
85% Lateral Corticospinal Tract fibers mostly affect __________ ___________________ Distal Flexor Muscles
distal flexor muscles are affected mostly by what tract and how much of it? 85% Lateral Corticospinal Tract
If 85% of motor fibers go to LCST, where does the other 15% go? to the Ventral Corticospinal Tract!
15% Ventral Corticospinal Tract fibers are separated from the 85% Lateral Corticospinal Tract fibers and DO NOT CROSS.
the 15% Ventral Corticospinal Tract fibers descend to the appropriate level, then they finally cross the VWC at their level of exit and synapse onto interneurons then to LMN's or they synapse directly onto LMN's
Like Pain & Temp (Lat Spinothalamic tract) trick was 2 doors up to synapse, what's the trick with the Ventral Corticospinal Tract? the 15% VCST does not cross until it reaches its exit level, unlike it's sister fibers of 85% Lateral Corticospinals that cross at the great pyramidal decussation.
the ventral corticospinal tract 15% fibers effect what kind of muscles core. 15% is core VCST.
15% is Core VCST.
Core VCST is 15%
white matter ascending pathways 1. Fasiculus Gracilis (no proprio) and Fasiculus Cuneatus 2. Spinocerebellar Tracts 3. Dorsolateral Fasiculus and Lateral Spinothalamic Tract, Ventral Spinothalamic Tract
white matter descending pathways 1. Lateral Corticospinal Tract 85% to distal flexors 2. Ventral Corticospinal Tract 15% to core muscles
a spinal pathway syndrome (2) Brown-Sequard and Syringomyelia
a lesion of white matter on one side is called a ___________ hemisection
name syndrome resulting from a lesion of white matter on one side (hemisection) Brown-Sequard Syndrome
Brown-Sequard syndrome is a hemisection through the cord. How many pathways affected? Deep sense dorsal columns, Pain & Temp of lateral spinothalamic 2 DOORS DOWN, Light Touch ventral spinothalamic, Lower body proprioreception spinocerebellar, LMN/flaccid Lateral and Ventral Corticospinal tract, DLF-loss of P&T @ THAT level!!!
Why doesn't Brown-Sequard include Medial Lemniscus, and nucleus cuneatus/gracilis affected areas? Because Brown-Sequard is only about white matter in the spinal cord and those areas are in the medulla. Anything after a brainstem decussation doesn't count.
Brown-Sequard affects Deep Sensibility. How? Deep sense is dorsal columns to medial lemniscus to thalamus. F. Cuneatus has VDPP while F.Gracilis has VDPressure, no proprio. B.S. kills F.Cuneatus T6up all VDPP, kills F.Gracilis T6down (no proprio) IPSILATERALLY from level of lesion on down. 1*neuron.
Brown-Sequard affects Pain & Temperature. How? P&T is lateral spinothalamic tract. Lesion to spinal cord knocks out CONTRALATERAL pain&temp. Knocks out pain&temp ipsilaterally, @ THAT LEVEL for the next TWO levels down! DLF is ipsi, LST is contralateral. Both are Pain & Temperature.
Brown-Sequard affects proprioception from lower limb. How? Spinocerebellar tracts are ipsilateral to cerebellum and a lesion would cause ataxia (unsteady gait)
Brown-Sequard affects motor function. How? Lesion to lateral corticospinal is after pyramidal decussation so now stops UPPER MOTOR neuron from synapsing directly to LMN or to an interneuron in ventralhorn means loss of motor to distal flexors from UMN so Ipsilateral SPASTIC paralysis (UMN)
Brown-Sequard affects Lateral Corticospinal Tract how? Ipsilateral Spastic Paralysis (UMN paralysis)
What characterizes Brown-Sequard syndrome? Dissociated Sensory loss - loss of one sensation (e.g. deep sensibility from ipsilateral side) on one side, and loss of another (e.g. pain and temperature contralateral side) from the other side
dissociated sensory loss loss of one sensation (eg, deep sense) from one side, and loss of another kind of sensation (eg. pain and temperature) from the other side
dissociated sensory loss is a characteristic of Brown-Sequard Syndrome
when would you have ipsilateral loss of Pain & Temp with Brown-Sequard? lesion to DLF at level of lesion and the two below it.
syringomyelia expansion of the central canal into the spinal cord destroys the ventral white commissure first, then progresses laterally and dorsally.
what part of the white matter is destroyed first in SYRINGOMYELIA Ventral White Commissure, the lateral and dorsal
Affect of lesion in Syringomyelia VWC destroyed first BILATERAL segmental loss of Pain and Temp at 2 levels below the lesion ONLY
why would bilateral loss of pain and temperature at two levels below the lesion ONLY occur with Syringomyelia? The VWC is obliterated so no second order neurons may cross from nucleus proprius to lateral spinothalamic (pain & temp) on EITHER side - ergo, BILATERAL. Two levels below lesion is because P&T fibers enter DLF two levels above.
Syringomyelia expands central canal into spinal cord. First VWC, then dorsolaterally. BILATERAL loss of Pain & Temperature 2 segments below lesion AT THAT SEGMENT ONLY.
Internal anatomy of the medulla oblongata: in the lower medulla, is the 4th ventricle seen? No - see slide of "lower medulla - caudal to olive"
lower medulla pathway for deep sensibility:In the lower medulla at the level of the inferior olivary nucleus, what do Fasiculus Gracilis 1* first order afferents synapse to? 2* second order neurons in Nucleus Gracilis
In the lower medulla, Fasiculus Cuneatus 1* afferents synapse to (deep sense) 2* second order neurons in Nucleus Cuneatus
the 1* axons of both fasiculus gracilis and cuneatus, synapsing with 2* afferents in respective nuclei, cross to the opposite side of the medulla via the great sensory decussation
Hello! What is the difference between the pyramidal decussation and the Great Sensory Decussation? pyramidal decussation is ventral, where descending motor corticospinal afferents cross to become contralateral. Great Sensory Decussation is more dorsal, where dorsal fasiculi afferents (N.G. & N.F.) cross in deep sensibility/medial lemniscus tract
the Great Sensory Decussation must be dorsal because it is sensory!
The pyramidal decussation must be ventral because it has the pyramids
after 2* afferents from nucleus gracilis and nucleus cuneatus board arcuate fibers in the deep sense pathway, where do they go? arcuate fibers carry these 2* afferents ACROSS to the medial lemniscus opposite, and there they ascend to the thalamus via the medial lemniscus tract of fibers for deep sensiblity.
the Medial Lemniscus carries 2* afferents carrying deep sensibility from the contralateral half of body (Medial lemniscus signifies having crossed the Great Sensory Decussation)
I sailed my ship, the F.Cuneatus, to the port city of Nucleus Cuneatus where I resupplied with a new crew. We left port Nucleus Cuneatus on the Arucuate Fiber tradewinds, and crossed the Great Sensory Decussation to find ourselves spotting "Land, ho!" the isle of Medial Lemniscus in the Deep Sensibility sea, out past the Great Sensory Decussation. Our cargo is still the same (Vibration, Discrimination, Pressure, Proprioreception and Stereognosis) as we travel to the Thalamus!
Lower Medulla: spinocerebellar tracts at inferior olive level do what? carry proprioreception from the lower body
propriorecption from the lower body is carried within the dorsal columns via the spinocerebellar tracts (white, ipsilateral matter on either side of spinal cord)
Dorsal spinocerebellar tracts carrying proprioception from lower body enter near the DLR, then the cerebellum via the inferior cerebellar peduncle
where in the grey matter would you think proprioreception came from? #4,I am the Dor, I can feel Clarke's feet on the floor (Nucleus Dorsalis).
the _______spinocerebellar tract carries proprioreception from the lower body. It enters the cerebellum via the Inferior Cerebellar Peduncle. Dorsal = inferior cerebellar peduncle ipsilateral
key words for dorsal spinocerebellar tract at lower medulla Dorsal, spine to cerebellum, proprioception, lower body, inferior cerebellar peduncle, ipsilateral
the ________ _______________ enters the cerebellum via the Superior cerebellar peduncle. Ventral Spinocerebellar tract
why would it make sense for the dorsal spinocerebellar tract to enter the cerebellum lower (inferiorly) and the ventral spinocerebellar tract to enter the cerebellum from above (superiorly)? Dorsal spinocerebellar tract is schematically closer to the beginning of the inferior cerebellar peduncle at the medulla. There is no crossing. Straight up shot to the inferior cerebellar peduncle.
Name structures present for DEEP SENSIBILITY at lower medulla: 1-fasiculus and nucleus Gracilis 2-fasiculus and nucleus Cuneatus 3- Internal Arcuate fibers 4- Great Sensory Decussation 5- MEDIAL LEMNISCUS 6- Spinocerebellar tracts (Dorsal to ICP and Ventral to SCP)
pain and temperature not only come from the body but from the face
the lower medulla contains the pain and temperature pathway for the face
what part of the medulla contains pain and temperature for the face? Lower medulla
in the lower medulla, 1* afferent axons of pain and temperature from the ________face and other parts of the head enters the SPINAL TRACT OF THE TRIGEMINAL NERVE ipsilateral
where is the SPINAL TRACT OF THE TRIGEMNINAL NERVE found? lower medulla, next to and lateral to the dorsal columns and above the spinocerebellar tracts on the outskirts of the white matter
1* afferent axons of pain and temperature from the face and head enter the spinal tract of the trigeminal nerve
Which cranial nerve is the trigeminal nerve cranial nerve V (5) = Trigeminal
why is the SPINAL TRACT OF THE TRIGEMINAL NUCLEUS of the trigeminal nerve V for the face and head called as such? because its afferents are coming from the long spinal tract of the nucleus headed towards the sensory nucleus of the trigeminal
what does the trigeminal nerve do? (p341 in pocket atlas of human anatomy) Both sensory and motor; muscles of mastication and sensory info for facial sensation
1* afferent axons of pain and temperature from the IPSILATERAL face and head enter the ________________ and then enter the ____________ where they synapse with 2* afferents. first they enter the SPINAL TRACT of the Trigeminal Nerve (V) and then they move into the NUCLEUS of the Spinal Tract of the Trigeminal Nerve (V) and synapse!
what happens to the 1* afferent sensory axons from the face and head after they've been to the spinal tract of trigeminal and are now in the nucleus of the spinal tract of trigeminal nerve? they synapse and the 2* afferents cross the midline CONTRALATERAL to form the Trigeminal Lemniscus. As second order, contralateral afferents, they ascend as the trigeminal lemniscus to the Thalamus.
pain and temperature from face and head - spinal tract of trigeminal nerve - nucleus of spinal tract of trigeminal nerve (at lower medulla/inf olivary nucleus) - then what? cross over to trigeminal lemniscus (right dorsal/behind medial lemniscus) and follow trigeminal lemniscus 2* afferents together to thalamus with pain and temp from face and head
we know pain and temperature travels in the lateral spinothalamic tracts from the body to thalamus. Have the 1* afferent become 2* afferents before they hit the thalamus? yes, the pain and temp from body entered at DLF, synapsed at nucleus proprius, became *2 afferents and crossed the VWC over to the Lateral Spinothalamic tract. As 2* afferents, they ascend.
the 2*afferents traveling in the lateral spinothalamic tract from nucleus proprius cell bodies reach the lower medulla. Are they carrying ipsilateral or contralateral information, at this point? Contralateral (they became 2* at nucleus proprius then crossed the VWC to the lateral spino thalamic tract so they are 2* contralateral pain and temp from body)
once the 2* afferents in the nucleus of the spinal tract of the trigeminal nerve have crossed to the opposite trigeminal lemniscus in the lower medulla, are they ipsilateral or contralateral? Contralateral (they were 2* from their cell bodies in the nucleus of the spinal tract of trigeminal nerve when they crossed over to the opposite trigeminal lemniscus to ascend)
pain and temp are contralateral lower body when they travel in the ____________ and pain and temp from face/head are contralateral when they travel in the lateral spinothalamic tract, trigeminal lemniscus
where are the cell bodies from the trigeminal lemniscus in the nucleus of the spinal tract of the trigeminal nerve V on the opposite side
where are the cell bodies of the Lateral spinothalamic tract? in the nucleus proprius on the opposite side
on the dorsal side of the medulla, we find dorsal columns (fas. gracilis and fas. cuneatus) leading to the gracile tubercle (contains nucleus gracilis) and the cuneate tubercle (contains nucleus cuneatus) -these use the great sensory decussation
on the ventral side of the medulla, we find the pyramidal decussation and the pyramids, themselves, medial to the olives and inferior cerebellar peduncles
the pyramids contain what kind of fibers? CorticoSpinal fibers UMN from cortex to motor nuclei on the contralateral side of body
why do the pyramids contain corticospinal fibers that are contralateral/opposite to where they will synapse with motor nuclei? they are still contralateral corticospinal fibers in the pyramids because they have not descended far enough downward to cross the pyramidal decussation (ie, they haven't swapped sides yet)
the _________contain corticospinal fibers (UMNs) to the contralateral half of the body pyramids
At the pyramidal decussation, what happens to the corticospinal UMN fibers? they divide! 85% CROSS to form the Lateral Corticospinal tract contralateral to their origin in the cortex, and 15% stay ipsilateral to become the Ventral Corticospinal tract.
lesion corticospinal before pyramidal decussation and what happens? spastic paralysis (both ipsi and contra are affected)
what tract in the lower medulla connects cranial nerve nuclei and autonomic centers to coordinate vestibular input and head, neck, and eye movements? Medial Longitudinal Fasiculus
your mother is a MLF - I always turn my head and look at her, following her with both eyes! Medial Longitudinal Fasiculus of lower medulla coordinates head, neck, and eye movements between cranial nerves and autonomic centers. MLF allows conjugate (together) horizontal eye movements.
Medial Longitudinal Fasiculus begins in the lower medulla, near the inferior olivary nucleus level. It is situated "behind" or dorsal to the trigeminal lemniscus, then the medial lemniscus.
the MLF coordinates head, neck, and horizontal conjugate eye movements (VESTIBULAR INFO) between what two entities? cranial nerves and autonomic nervous system
what fasiculus is involved in coordinating vestibular information between the cranial nerves and the autonomic nervous system? Medial Longitudinal Fasiculus (MLF) beginning at lower medulla
last structure in lower medulla is the reticular formation. what is this responsible for? consciousness and alertness. Reticular formation is shot is comatose people. RF makes sure you wake up in the morning.
the ________ _________is a diffuse area in the brainstem with small nuclei and fibers. Reticular Formation
the Reticular formation is responsible for ______ functions, both sympathetic and parasympathetic, and includes cardiovascular and respiratory centers. autonomic
if you lesion the reticular formation, not only will you lose consciousness/alertness, you will lose cardiovascular and respiratory
Reticular means retaining wall or fibers, like retinaculum. The Reticular Formation helps you retain consciousness, alertness, breathing and heartbeat.
what system is the reticular formation part of? reticular activating system (consciousness)
the ______ ____________ __________monitors sensory stimui and determines what gets up to conscious levels Reticular Activating System that begins in the lower medulla
lesions of the Reticular formation may lead to coma and death
name the lower medulla structures at the lowest level that are different from structures of the uppermost spinal cord MLF, Reticular formation, Pyramids (Corticospinal tract), Pyramidal Decussation (Lateral and Medial Corticospinal tracts), Medial lemniscus, Trigeminal Lemniscus, Nucleus of the Spinal Tract of Trigeminal V, Spinal Tract of the Trigeminal V
what structures at lower medulla are continuations/same as those at uppermost spinal cord? dorsal (inferior cerebellar peduncle) and ventral (superior cerebellar peduncle)spinocerebellar tracts, Nucleus Gracilis, Nucleus Cuneatus, Lateral Spinothalamic tracts
why isn't the spinal tract of the trigeminal V nor the nucleus of spinal tract of trigeminal V anywhere before the medulla level? because it carries pain and temp from face and head. you wouldn't want it to get too far from the source!
See slide of MIDDLE MEDULLA (mid-olive) did you look at the slide?
in the Middle Medulla, what extension of the canal for cerebrospinal fluid is now visible, where it was not visible in the lower medulla? 4th ventricle
What structures continue from lower medulla to middle medulla (mid-olive)? There are 8: 1-MLF, 2-Trigemninal Lemniscus (larger, still on Medial Lemniscus), 3-Medial Lemniscus (much longer), 4-Spinal Tract of Trigeminal V, 5-Nucleus of spinal tract of trigeminal V, 6-Spinothalamics (pain/temp),7-RF (conscious), 8-Pyramids (motor)
remember identifying the parts of the 4th ventricle below the striae medullaris? Think of the nerve that comes out preolivary, and the three that come out post olivary sulcus. Do that now... hypoglossal trigone (hypoglossal comes out preolivary on dorsal side), vagal trigone (vagus exits at post olivary sulcus on dorsal side), vestiublar area (vestibulocochlear exits post-olivary sulcus on dorsal), inferior medullary vellum (hooks on diagram)
What does the hypoglossal cranial nerve do? CN XII - motor nerve supplying tongue
where is the hypoglossal nucleus situated? right in front of 4th ventricle, most medial, at level of mid-olive in middle medulla
the Hypoglossal Nucleus contains cell bodies of LMNs to ipsilateral tongue muscles
all cranial nerves are ipsilateral to their effect, except CN IV, Trochlear Nerve
the hypoglossal nucleus (tell me everything) situated at mid olive of middle medulla, most medial, external feature is hypoglossal trigone, contains cell bodies of LMN's to ipsilateral tongue
where are the axons of the hypoglossal CN XII if the cell bodies for the LMN's ipsilateral tongue are in the motor nuclei? the axons are in the Hypoglossal nerve XII itself, running towards the ventral exit at pre-olivary sulcus (middle medulla, mid-olive level)
in gross III abdomen, you learned that the spinal nerves supply sympathetic and the vagus nerve supplies parasympathetic for the abdominal organs. What nucleus is in the middle medulla (mid-olive level) that supplies parasympathetic innervation? DORSAL MOTOR nucleus of the Vagus CN X, parasympathetic to respiration, heart, GI
where in the middle medulla (mid-olive) is the DORSAL MOTOR nucleus of the Vagus CN X? lateral to the Hypoglossal X nucleus, but medial to the Vestibular area, in the 4th ventricle is labeled externally as the Vagal trigone below the striae medullaris
where does the vagus nerve exit to feed parasympathetic respiratory, heart, and GI from the middle medulla/mid-olive? post-olivary sulcus, it emerges with Glossopharyngeal IX and passes through jugular foramen. On slide, it is the only laterally placed nerve emerging ventral to the inferior cerebellar peduncle, dorsal to inferior olivary nucleus
what does the DORSAL MOTOR nucleus of the Vagus X contain? parasympathetic cell bodies for respiratory, heart, GI
what is lateral to the vagal trigone? vestibular area
what is in the vestibular area of the middle medulla (mid-olive) at inferior olivary nucleus level/4th ventricle level? FOUR Vestibular Nuclei (4 vestiubules for 4 tents, lined along the lake)
There are Four _______ _______ receiving afferents from the Vestibulocochlear nerve CN VIII for balance and equilibrium at the middle medulla level. Vestibular Nuclei
there are four vestibular nuclei receiving afferents from the ___________ ___________ CN ___ for balance and equilibrium at the middle medulla level. Vestibulocochlear Nerve, CN VIII
there are 4 vestibular nuclei receiving afferents from the Vestibulocochlear Nerve (CN VIII) for ____________and________at the middle medulla level. balance and equilibrium
how many vestibular nuclei for balance and equilibrium at the middle medulla level? four
where do the four vestibular NUCLEI receiving afferents from the Vestibulocochlear Nerve (CN VIII) for balance and equilibrium project? they project to the spinal cord, cerebellum, and MLF.
why would the vestibular nuclei receiving afferents from the vestibulocochlear nerve VIII for balance and equilibrium project to the MLF, among other things? because the Medial Longitudinal Fasiculus is a tract connecting cranial nerve nuclei and autonomic centers to coordinate vestibular input and head, neck, and eye movements (your mother is a MLF - a real headturner that requires both eyes!)
the four vestibular nuclei of CN VIII project to the MLF, spinal cord, cerebellum
the solitary tract and nucleus receives fibers from the ______ nerve, Glossopharyngeal nerve, and Vagus nerves. Facial
the solitary tract and nucleus exists at the level of middle medulla (mid-olive) at inferior olivary nucleus
why is it reasonable to expect the solitary nucleus to exist at the middle medulla? because the dorsal motor nucleus of vagus X is a parasympathetic nucleus for respiratory, heart and GI (VASOMOTOR)- the solitary tract and nucleus is involved in the afferent autonomic limb of visceral reflexes (VASOMOTOR)of cardiovascular and GI systems
what receives taste fibers from facial, glossopharyngeal, and vagus nerves? solitary tract and nucleus
the Solitary Tract and Nucleus is located between the Dorsal MOTOR nucleus of Vagus and the Vestibular Nuclei, facing the 4th ventricle (see slide of same)
from where does the solitary tract and nucleus receive taste fibers? facial, glossopharyngeal, vagus (7.9.10 - why not vestibulocochlear? I was alone when I 8 it!)
7.9.10 - I was alone when I 8 it! the solitary tract and nucleus receives TASTE fibers from 7.9.10 but not 8
Besides receiving taste from 7.9.10 (I was alone when 8 it!), the solitary tract and nucleus is involved in afferent autonomic limb of vasomotor to heart and GI
name the 4 new things in the middle medulla (mid-olive) level along the 4th ventricle side: Hypoglossal Nucleus, Dorsal Motor Nucleus of Vagus, Four Vstibular Nuclei, Solitary Tract and Nucleus
what MIGHT BE the motor nucleus (LMNs) to the ipsilateral muscles of the Larynx, Pharynx, and Palate Nucleus Ambiguus
If the Nucleus Ambiguus were actually the motor nucleus (LMNs) to the ipsilateral muscles of the Larynx, Pharynx and palate, what cranial nerves would be involved? Glossopharyngeal IX (pharynx, stylopharyngeus, post 1/3 tongue), Vagus X (tastes, swallows, lifts palate), Accessory XII(cranial root joins vagus -tastes,swallows,lifts palate),
what cranial nerve innervates the stylopharyngeus muscle? Glossopharyngeal Nerve IX
what do you figure are the origin and insertion, and action, of the stylopharyngeus muscle? styloid process to pharynx, help constrict pharynx (yup, I looked it up)
what does the statement, "X and XI innervate other laryngeal, pharyngeal, and palatal muscles by means of the Vagus X" mean? How is that possible? the Accessory CN XI has a two roots (cranial and spinal) and the cranial exits with the Vagus to supply ipsilateral muscles of the larynx, pharynx, and palate.
Lesion of the Nucleus Ambiguus OR Vagus X leads to: dysphonia, dysphagia, uvula deviation to good side
dysphonia hoarseness, caused by lesion to Nucleus Ambiguus or Vagus X - what makes you hoarse? Inability to swallow. Who is responsible for swallowing? Nucleus Ambiguus and Vagus. Why Nucleus Ambiguus? Because it's motor to Glossopharyngeal, Vagus, and Accessory.
dysphagia difficulty swallowing.
what structures at the middle medulla are responsible for swallowing? Nucleus Ambiguus and Vagus
Why are the Nucleus Ambiguus and Vagus at middle medulla responsible for dysphonia and dysphagia, and deviation of uvula to good side, if lesioned? Because they contain the motor nuclei (LMNs) to the larynx, pharynx, and palate so if they are lesioned, flaccid paralysis sets in. You need your muscles LMNs to swallow, so hoarseness and difficulty swallowing would result from lesion/flaccid paralysis.
is the solitary tract and nucleus involved in swallowing? NO, it receives taste afferents from 7.9.10 (I was alone when I 8 it!)
what is more dorsal- the solitary tract and nucleus or nucleus ambiguus? Solitary tract and nucleus are between dorsal motor nucleus of vagus (vagal trigone) and four vestibular nuclei (vestibular area). Nucleus ambiguus halfway "down" the vagus nerve and medial. SEE SLIDE
what leads to dysphonia, dysphagia, and deviation of the uvula to the good side (all flaccid paralysis) lesion to the Nucleus Ambiguus or Vagus, which are the motor nuclei LMNs to the larynx, pharynx and palate. Injury to LMN results in ipsilateral flaccid paralysis.
the Inferior Olivary Nucleus is involved in Motor control
the Inferior Olivary Nucleus is at the level of middle medulla
the Inferior Olivary Nucleus receives input from the spinal cord, cortex, and other areas. It projects its fibers to the CEREBELLUM (remember: superior from midbrain crus cerebri to superior cerebellar peduncles, pons to middle cerebellar peduncles, lateral fasciculus (dorsal spinocerebellar tract) to inferior cerebellar peduncles.
The inferior olivary nucleus projects to cerebellum, via olivo-cerebellar fibers.
the Inferior Cerebellar Peduncles contains the dorsal spinocerebellar tract and olivocerebellar fibers
is the ventral spinocerebellar tract included in the inferior cerebellar peduncle fibers to the cerebellum? NO, the ventral spinocerebellar tract enters the cerebellum superiorly, so it must enter with the superior cerebellar peduncles from the midbrain.
3 new structures of middle medulla, besides hypoglossal nucleus, dorsal motor nucleus of vagus, solitary tract and nucleus, four vestibular motor nuclei: nucleus ambiguus, inferior olivary nucleus, inferior cerebellar peduncles
see slide for summary of middle medulla structures did you see the slide?
Name the nerves associated with the medulla: 8,9, 10, 11, 12: Vestibulocochlear, Glossopharyngeal, Vagus, Accessory, Hypoglossal
(CN VII) VESTIBULOCOCHLEAR nerve -name the nuclei of the vestibulocochlear n. 1- four vestibular nuclei in middle medulla and pons2- cochlear nuclei in medulla
Upper Medulla is near pontomedullary junction
in the upper medulla, near the pontomedullary junction, the 4th ventricle is wide open, baby!
see slide for upper medulla near pontomedullary junction junction is where 6,7, and 8 come out visually
what two structures are missing from the diagram of the upper medulla that were present in the middle medulla? hypoglossal nerve and nuclei XII, and Vagus nerve and dorsal motor nuclei X
in the upper medulla near the pontomedullary junction, what nucleus receives fibers involved in hearing from the Vestibulocochlear nerve VIII? Dorsal COCHLEAR nucleus - remember, the 4 vestibular nuclei were at the vestibular area level of middle medulla. Now we get the cochlear (ear) level which is higher.
the _________ ___________ receives fibers involved in hearing from the vestibulocochlear nerve VIII at the upper medulla level Cochlear nucleus (Hearing is cochlear)
the ________ fibers are axons involved in motor control from the inferior olivary nucleus coursing to the contralateral cerebellum Olivocerebellar fibers going to Inferior Cerebellar Peduncle (olivocerebellar and dorsal spinocerebellar)
Two structures at upper medulla near pontomedullary junction that are new: Cochlear Nuclei for hearing (VIII receiver) and Olivocerebellar fibers crossing to contralateral Inferior Cerebellar Peduncle
if you lesioned the olive at upper medulla near pontomedullary junction, what would happen? depends: the inferior olivary nucleus is UMN involved in motor control If you lesion the olive before upper, then it's ipsilateral spastic paralysis. IF you lesion the olive at the upper when they are crossing, then it's contralateral spastic paralysis.
nuclei of VESTIBULOCOCHLEAR nerve VIII located: four vestibular nuclei (medulla & pons) and cochlear nuclei (upper medulla)
function of VESTIBULOCOCHLEAR nerve VIII: balance and equilibrium, hearing
which vestibulocochlear nuclei are responsible for balance and equilibrium and where are they? four vestibular nuclei of middle medulla upwards through pons
lesion of VESTIBULOCOCHLEAR nerve VIII vertigo, nystagmus, vomiting and loss of hearing
nystagmus Nystagmus (mostly vertical identification) is a normal symptom, when eyes shift back and forth between trees while driving or printed lines on painting. When that happens without any prompt, that’s bad. Named for FAST component.
the facial nerve (7) and vestibulocochlear nerve (8) exit at the cerebellopontine angle
vertigo, vomiting, nystagmus (vertical ID) and hearing loss are the result of a lesion to the Vestibulocochlear Nerve CN VIII
the Vestibulocochlear nerve VIII is associated with mid medulla to pons for 4 vestibular nuclei and upper medulla for cochlear nuclei
GLOSSOPHARYNGEAL nerve CN IX nuclei: 1-solitary nucleus (middle medulla) is taste from 7.9.10 (I was alone when I 8 it) and visceral reflexes from heart and GI, 2-nucleus ambiguus (middle medulla) larynx, pharynx, and palate LMNs ipsilateral, 3-inferior salivatory nucleus is parasympathetic
solitary nucleus is associated with 3 cranial nerves 7.9.10 (I was alone when I 8 it)
nucleus ambiguus is associated with 3 cranial nerves post olivary sulcus nerves 9-10-11
inferior salivatory nucleus must be a ___________ nerve because you wouldn't want to have to voluntarily keep track of your own saliva production parasympathetic
name the 3 nuclei that have ties to Glossopharyngeal CN 9 7.9.10 (I was alone when I 8 it), post-olivary nerves 9-10-11, and remote saliva control are: solitary nucleus, nucleus ambiguus, inferior salivatory nucleus
function of GLOSSOfPHARYNGEAL nerve #9 taste from post 1/3 tongue (with Vagus) - stylopharengeus muscle (motor)-sensory to tympanic cavity, auditory tubes, upper fPHARYNX, soft palate, post 1/3 tongue -visceral carotid body & sinus monitor -parasymp to parotid saliva gland
you should write down the functions of glossopharyngeal nerve on a dry erase board. there are 10 fcns: post 1/3 tongue taste and motor, stylopharngeus motor, carotid body sense, inner ears to upper fPHARYNX and palate sensory, parasymp to parotid!
lesion of GLOSSOfPharyngeal CN #9 *loss of sensation OR intense pain to upper fPharynx*reduced or absent GAG! reflex (stylopharyngeus contracts pharynx)*hypertension/hypotension from no carotid body monitor
Nuclei of VAGUS X: dorsal motor nucleus of vagus at middle medulla (parasympathetic)/ nucleus ambiguus (9-11 motor nucleus ipsilateral muscles pharynx, larynx, palate - dysphonia,dysphagia, uvula deviation good side) /solitary nucleus (taste 7.9.10 I was alone when I 8 it)
dorsal motor of vagus at middle medulla is a ___________ nucleus, mostly for the Vagus Nerve (CN X) for the respiratory, heart, GI parasympathetic
solitary tract and nucleus receives _______ fibers from 7.9.10 and is also involved in visceral reflexes of cardio and GI taste! (I was alone when I 8 it!) & visceral reflexes
name nuclei of vagus X dorsal motor nucleus of vagus (parasymp), nucleus ambiguus (motor to face), solitary nucleus (sensory taste and visceral reflexes)
function of VAGUS X (only half are listed here) parasympathetic to thoracic and abdominal viscera - motor to pharyngeal constrictors, intrinsic laryngeal, palatal muscles for phonation and swallowing, which is why you get dysphonia, dysphagia, and uvula deviation if you lesion Vagus or Nucleus Ambiguus
Nucleus Ambiguus is the _______ nucleus (LMNs) to ipsilateral muscles of what through which cranial nverves? motor nucleus to ipsilateral muscles of pharynx, larynx, palate through 9,10,11 cranial nerves
which cranial nerve innervates the stylopharengeus muscle? 9 Glossopharyngeal (pharyngeal is in the name - this is the only motor fcn of glossopharyngeal - all else is sensory)
the vagus nerve is parasympathetic to the _______________________________ and motor to the ___________________________________ thoracic and abdominal viscera, pharyx, larynx, palate muscles for constriction, phonation and swallowing, taste from larynx to epiglottis, sensory to larynx, little of external ear, meninges in posterior cranial fossa and foramen magnum
Lesion to the Vagus X loss of parasympathetics to thoracic and abdomninal viscera (bye, bye! this includes the heart, respiratory, and GI), as well as dysphonia and dysphagia
taste from larynx to epiglottis and sensory to larynx, small portion of the external ear, meninges in cranial fossa and foramen magnum are all functions of what cranial nerve? Vagus X (most of these are vagal maneuver recipient functions - i.e., tap your ear to stifle vomiting or gag reflex, etc. Look up Vagal Maneuvers on Wiki)
a lesion of the vagus nerve will cause a loss of parasympathetics to thoracic and abdominal visceral and dysphonia, dysphagia
Nucleus Ambiguus and disperse cell bodies in medulla and cervical spinal cord are nuclei of ACCESSORY nerve 11
Nuclei of Accessory CN IX: Nucleus Ambiguus (9/11), various cell bodies in medulla and cervical spinal cord (CN 11 has a cranial and spinal root, remember?)
function of Accessory Nerve 11: cranial root: motor to pharynx, larynx, palate mm (runs with Vagus)spinal root: motor to trapezius and SCM (turns head, lifts shoulder)
Lesion to Accessory nerve 11: cranial: dysphonia,dysphagia (like Vagus and Nucleus Ambiguus lesion)spinal: cannot move (paralysis) of ipsilateral trap and SCM
medullary syndromes (2) MEDIAL medullary syndrome & LATERAL medullary syndrome
what structures are affected in MEDIAL medullary syndrome? medial lemniscus, pyramid, hypoglossal nerve fibers (see slide of middle medulla if you don't know where these are)
crossed paralysis MEDIAL medullary syndrome - paralysis of one side of the body and the other side of the head/face
why would crossed paralysis result in medial medullary syndrome? *Medial lemniscus, pyramids, hypoglossal nerve fibers Medial lemniscus deep sensibility from F. Cuneatus and VDD from F. Gracilis that cross Great Sensory Decussation, synapse 2* at medial lemniscus -Pyramids carry UMN motor ventral corticospinal pathways, 15% ipsi spastic paralysis-CN 12 ipsi spastic tongue
LATERAL medullary syndrome affects what structures? Spinothalamic tracts, Spinal Tract and Nucleus of Trigeminal Nerve
why would spinothalamic tracts be affected by LATERAL medullary syndrome? Lateral spinothalamic tracts carrying 2*afferents from Nucleus Proprius for P&T from 2 doors down so contralateral LOSS P&T. Ventral spinothalamic tract light touch 2*afferents contralateral loss light touch.
Dissociated sensory loss a sensory loss on one side of the body and the other side's head/face
what syndrome is Crossed Paralysis associated with and why? Crossed is paralysis so MEDIAL medullary because pyramids are UMN spastic motor to lower body and hypoglossal is LMN motor to tongue so flaccid tongue
Dissociated Sensory Loss is a great description for the Lateral (L for Loss & Lateral) Medullary Syndrome of spinothalamic (pain & temp)contralateral crossed VWC from N.P. and spinal tract and nucleus of trigeminal (pain & temp from face/head)ipsilaterally because they haven't crossed to trigeminal lemniscus
all cranial nerves themselves within the cross-sections of the medulla or pons or midbrain are upper or lower motor neuron? Paralysis? LMN, flaccid, all ipsilateral except trochlear that crosses around periaqueductal grey
the HYPOGLOSSAL nerve 12 located from nucleus of hypoglossal nerve (internal)at hypoglossal trigone (visual)in 4th ventricle - exits in pre-olivary sulcus at middle medulla - motor to tongue muscles
HYPOGLOSSAL nerve XII nuclei: hypoglossal nucleus at middle medulla (mid-olive)
HYPOGLOSSAL nerve 12 function motor to muscles of tongue (except palatoglossus - guess which one does that?)
HYPOGLOSSAL nerve 12 lesion: ipsilateral flaccid (nerves are LMNs) paralysis of tongue and atrophy
the palatoglossus muscle is innervated by the cranial nerve responsible for the same one motor to stylopharyngeus muscle. The palatoglossus forms a ring around food bolus, constricts, makes suitable swallowing size.Stylopharyngeus constricts pharynx. CN? Glossopharyngeal nerve IX/9 -when lesioned, lose sensation/pain to upper pharynx, reduced or absent gag reflex, hypertension/hypotension
what are the two syndromes associated with medulla and which terms describe them best? Lateral medullary syndrome=dissociated sensory LOSS, Medial medullary syndrome=crossed paralysis (pyramid and hypoglossal, even though medial lemniscus for p&t is also included)
Lateral medullary syndrome, apart from Dissociated Sensory Loss, may also affect other structures: (think Lateral medulla structures) four vestibular nuclei or connections -cerebellar connections (Inf cere ped and olive), Reticular formation (autonomic causes HORNer's syndrome)-Nucleus ambiguus (9+10), Solitary tract and Nucleus (7.9.10 + visceral reflexes)
Horner's syndrome can result from Lateral medullary syndrome (deep sensory loss)by affecting RETICULAR FORMATION - define Horner's syndrome... meiosis (pupillary constriction), ptosis (drooping eyelid), anhydrosis (lack of sweating) of ipsilateral half of face
meiosis pupillary constriction - (Horner's-RF-Lat Med Syn)
ptosis drooping eyelid - (Horner's-RF-Lat Med syndrome)
anhydrosis lack of sweating to ipsilateral face for Horner's-RF-Lat Med syndrome
name symptoms of lateral medullary syndrome Dissociated Sensory Loss: spinothalamic tracts, spinal nucleus/tract of Trigeminal, vestibular nuclei, cerebellar cx, autonomic RF HORNERs (meiosis, ptosis, anhydrosis), Nucleus ambiguus 9+10, Solitary tract and nucleus (7.9.10.11 I was alone when I 8 it)
_______is the structure between the medulla and the midbrain PONS
POns is subdivided into 2 structures: basilar pons (anterior shield), tegmentum of pons (everything between basilar pons and 4th ventricle -transverse section shows best)
2 pons parts: basilar pons (anterior), tegmentum of pons (basilar to 4th v.)
the _________ ___________ ___________lies lateral to the Trigeminal Nerves V. Middle cerebellar peduncle
what does the middle cerebellar peduncle of the pons, lateral to the Trigeminal nerve V, contain? fibers entering the cerebellum from the pontine nuclei
How do fibers from the pontine nuclei in the basilar pons enter the cerebellum? the middle cerebellar peduncle (remember: inferior c.p. is for medulla, middle c.p. is for pons, and superior c.p. is for midbrain)
structures BASILAR at lower pons corticospinal fiberspontine nuclei
structures at TEGEMENTUM of Lower pons Medial lemniscus, Trigeminal Lemniscus, and Spinothalamic tracts continue; Nucleus & Spinal Tract of Trigeminal; your mother is a MLF; Reticular Formation; Lateral Lemniscus; Abducens nucleus; Facial nerve wrapping around Abducens, Facial nucleus
BASILAR PONS has what running through it from cortex to spine, carrying motor to ventral horn motor nuclei in cord? Corticospinal fibers (cortex-crus cerebri-basilar pons-pyramids-decussation-15% ventral for core muscles, 85% lateral for distal flexors)
BASILAR PONS has what going from pons to cerebellum, receiving messages from cortex? Pontine nuclei are getting messages from cortex, then bundling into the middle cerebellar peduncles and heading to cerebellum
TEGMENTUM of PONS has what 3 structures continuing on to thalamus from medulla? 1.Medial Lemniscus, 2.Trigeminal Lemniscus, 3.Spinothalamic Tracts (Lateral & Ventral)
why would the Medial Lemniscus, Trigeminal Lemniscus, and Lateral/Ventral Spinothalamic tracts pass all the way through the pons? because deep sensibilities, face/head sensory, and pain & temperature from body are all registered in the relay system of the Thalmus, which has yet to be reached!
in the Tegmentum of the lower pons, the LATERAL LEMNISCUS carries auditory fibers from cochlear system to inferior colliculus
why don't we see the lateral lemniscus until the tegmentum of the lower pons? because the ears are with vestibulocochlear nerve and that comes out at cerebellopontine angle with facial nerve
your ears are on either side of your head, MOST lateral features you have. Let's call their lemniscus the... Lateral lemniscus (of tegmentum of lower pons)
the Nucleus and Spinal tract of the Trigeminal V are still at tegementum of lower pons. Why? because they are on the way to the thalamus (sensory to face/head -Pain & Temperature!!!)
Your MLF is still around at the Tegmentum of the lower pons. Where is it and what does it do? Medial Longitudinal Fasiculus started at lower medulla, connecting cranial nerve nuclei and autonomic centers to coordinate vestibular input and head/neck/eye movements. At tegementum of lower pons, it coordinates eye synchronicity.
The Reticular Formation NUCLEI and fibers are at the tegmentum of lower pons, too. What do they do here? RF started at lower medulla; autonomic fcns (symp&parasymp) of cardio and respiratory. The REticular ACtivating SYstem keeps us alert/awake/CONSCIOUS. Monitors sensory stimuli and decides what gets conscious. Coma or death if lesioned.
again with the lateral lemniscus at tegmentum of lower pons? carries auditory fibers from cochlear sys to inferior colliculus
at what level is the vestibulocochlear nerve? Vestibular nuclei (medulla and pons), cochlear nuclei (medulla)
where do the cochlear nuclei live? (think butterflyupper section of medulla with VC VIII coming out of sides) See slide of upper medulla the DORSAL COCHLEAR NUCLEI are at the upper medulla level, at the end of each vestibulocochlear nerve, lateral to the inferior cerebellar peduncle receiving fibers from inferior olivary nucleus
what structure is sitting at the bottom of the medial emninences, like big cat eyes on the floor of the 4th ventricle/dorsal tegmentum of pons? facial colliculi (one on either eminence, right above striae medullaris)
what structures of the tegmentum of the lower pons deep to the facial colliculus Abducens Nucleus, Facial Fiber Folded Fingerlike (around Abducens nucleus)
Where is the Facial Nucleus of the Facial Nerve? (see slide of tegementum of lower pons) at tegmentum level of lower pons, before facial foldsfingerlike around abducens nucleus, it begins at Facial Nucleus in Reticular Formation area, dorsal to Med lemniscus, Spinothalamic tracts, Lateral Lem, and Spinal/Nucleus of Trigeminal nerve
where does the Abducens VI nerve exit the pons? traverse from Abducens nucleus under facial colliculus straight ventrally to emerge at pontomedullary junction closest to midline.
What Laverne & Shirley song lyric helps us remember nerves visually associated with pons, however vestibulocochlear is both pons and medulla? (that is, if you were born before the show aired in 1976) five, six, seven, eight. Sclemeel, schlemazel, hasenfeffer incorporated. We're gonna do it! Give us any chance, we'll take it. Give us any rule, we'll break it. We're gonna make our dreams come true. Nothin's gonna turn us back now,
Midpons - what gigantic motor and chief sensory nuclei live right in the middle of the pons? TRIGEMINAL V! remember drawing of mesencephalic and spinal tracts coming up posterior to chief/principal sensory nucleus and the Motor nucleus sitting above it! They join forces and come out between basilar pons and middle cerebellar peduncle
the Motor Nucleus and Chief Sensory Nucleus of TRIGEMINAL nerve are in the MIDPONS, and the nerve exits between basilar pons and middle cerebellar peduncle
what two tracts sprout up and down from the chief sensory nucleus of trigeminal at MIDPONS how? MIDPONS<<mesencephalic tract up and back, while spinal tract down and back
what is the best visual clue that we are in the MIDPONS? the LOCUS COERULEUS becomes visible!
what is Locus Coeruleus responsible for? noradrenergic (Norepinephrine) nucleus that shuts off during REM sleep
Locus Focus Coeruleus is NE that is on all day, then shuts off during REM so you can rest
at what level does LOCUS focus COERULEUS become visible? midpons
At midpons, what giant "bumps" are sitting most posteriorly/dorsally, over the 4th ventricle superior cerebellar peduncles
name the new structures of midpons, vs. tegmentum of lower pons tegmentum of lower pons: lateral lemniscus, Abducens nuclei, Facial nerve and Nuclei, Middle Cerebellar peduncle, pontine nuclei traversing, corticospinal (motor) fibers descending, superior cerebellar peduncle
where is the acoustic tubercle? on the outside of the cochlear nucleus at upper butterfly medulla, practically IN the foramen of Magendie
LOCUS FOCUS is first visible at MIDPONS
Locus focus Coeruleus continues into UPPER pons
what is the most visible change from MIDpons to UPPER pons? the 4th ventricle has shrunk considerably! and there are no nerves (ie, Trigeminal) coming out
The medial lemniscus that was medial and sagittal in medulla has, by the UPPER pons, become completely flattened out and is a homologue of the body, with most lateral part the feet and so on into the head towards middle. It now lies on a coronal plane.
in the upper pons, what else besides a small 4th ventricle and a visible locus focus coeruleus exists? lateral lemniscus is much bigger (ears), superior cerebellar peduncle has shifted all the way to front with sup. medl.vellum, no middle cerebellar peduncles anymore, spinothalamic tracts are HUGE again! No Trigeminal nuclei or nerves-just mesencephalic tr
see slide of tegmentum of lower pons and basilar pons, midpons, and upper pons. did you look? I did.
what cranial nerves are associated with pons? Trigeminal V, Abducens VI, Facial VII, Vestibulocochlear VIII (also with medulla)
TRIGEMINAL V origins (4 nuclei): 1-nucleus of spinal tract of trigeminal (Pain & temp face)at midpons 2-chief sensory nucleus (touch) at midpons 3-motor nucleus (mastication mus.) @ midpons 4-mesencephalic nucleus (proprioception) @ midpons/midbrain
TRIGEMINAL V NUCLEI nuclei of spinal tract of trigeminal, chief sensory nuclei, mesencephalic nuclei, motor nuclei
of the 4 trigeminal nuclei, which is responsible for muscles of mastication? motor nucleus of trigeminal at midpons
of the 4 trigeminal nuclei, which is responsible for touch from the face/head? chief sensory nucleus of trigeminal at midpons
of the 4 trigeminal nuclei, which is responsible for proprioreception? mesencephalic nucleus of trigeminal from midbrain through to midpons to nucleus.
what does mesencephalic mean? tele dye mes met mye - it's the MIDBRAIN (tectum, tegmentum of midbrain, and superior cerebellar peduncles/crus cerebri)
of the 4 trigeminal nuclei, which is responsible for PAIN & TEMPERATURE from the face/head/neck? nucleus of the spinal tract of trigeminal, from C5 to midpons
which nucleus in the brainstem starts at C5 and ends in the midpons? the nucleus of the spinal tract of trigeminal (pain and temperature head/face/neck)
the trigeminal nerve is named as such because it has 3 branches: V1,V2,V3 or Opthalamic (s), maxillary(s), mandibular(b)
what are the 3 branches of the Trigeminal V? V1 Opthalamic (sensory), V2 Maxillary (sensory) , V3 Mandibular (both)
why does the order of the 3 branches of Trigeminal nerve easy to remember? They go medial to lateral according to structure: V1 Opthalamic, V2 Maxillary, V3 Mandibular and are sensory, sensory, mixed
which nerve just throbs over your teeth and in your maxillary sinus when you have a sinus infection? V2 Maxillary branch of Trigeminal 5 from midpons (probably chief sensory nucleus for touch and nucleus of the spinal tract of trigeminal for pain and temp)
sensory to face, scalp, teeth, most of tongue, oral and nasal mucosa, dura mater and cerebral blood vessels Trigeminal V (1Opthalamic and 2Maxillary sensory)
motor to the muscles of mastication Trigeminal V (3Mandibular mixed)
how do you examine the Trigeminal nerve for pathologies? cotton swab (chief sensory), pain by pinprick (nucleus of spinal tract of trigeminal), temperature (nucleus of spinal tract of trigeminal, corneal reflex (1Opthalamic branch), jaw reflex (3Mandibular), masticatory movements (motor nucleus in midpons)
lesion to TRIGEMINAL V sucks! What happens? -Trigeminal neuralgia (tic douloureux)-Facial anesthesia or numbness-Inability or difficulty to bite down with jaw deviation to same side
what nerve gets irritated when you have a cold and are constantly reaching for the tissues? trigeminal (nasal mucosa) -maxillary branch
when your "scalp crawls," what nerve is responsible? trigeminal (scalp) -opthalamic branch
when you bite your tongue, what nerve makes you swear out loud? trigeminal (sensory to most of tongue) -mandibular branch
what nerve tells the brain there's a bleed and swelling? Or a migraine due to vasodilation? trigeminal (sensory to dura mater and cerebral blood vessels) - branch depends on location - could be opthalmic or maxillary branch
with all of the things that hurt when you whack your head, bite your tongue, blow your nose too often, have a crawling scalp, and a migraine, what would this be called if it all happened at once, especially to the sensory parts? tic douloureux -trigeminal neuralgia which is a lesion of the trigeminal nerve
besides trigeminal neuralgia (tic douloureaux), what else can happen with a trigeminal lesion? facial anesthesia or numbness (opposite of tic douloureaux), inability or difficulty biting down (masticatory branch of trigemnial) with JAW deviation to SAME side
why would the jaw deviate to the same side if the trigeminal masticatory branch were lesioned? unilateral lesion would still work muscles of mastication
Abducens 6 is affiliated with what part of pons? exits at pontomedullary junction but it's motor nucleus is at LOWER pons level of facial colliculus, folded in the facial fibers.
what does the Abducens 6 do? EXTRAocular movements -ie, moves the extraoculuar muscle: (LR6, SO4)3 Lateral Rectus muscle
(LR6,SO4)3 (Lateral Rectus controlled by Abducens CN 6, Superior Oblique controlled by Trochlear CN 4) and all other extraoculars controlled by Oculomotor CN 3.
what is the origin of the Abducens 6 Abducent nucleus in Lower pons level of facial colliculus
what nerve is at the level of midpons, and is the ONLY nerve there? Trigeminal (the Facial nucleus and Abducent nucleus are almost dead level with pontomedullary junction), just spaced apart
exit of Abducens 6 nerve? pontomedullary junction (between basilar pons and pyramid)
what is the function of Abducens 6 move the Lateral Rectus muscle (LR6)
when you can't move your eye laterally, what happens? you get medial strabismus
medial strabismus medially stuck eye because lesion of Abducens 6 may have affected Lateral Rectus
how would you examine the Abducens 6 nerve function? motor to Lateral Rectus so lateral eye movement exam. STuck? Then medial strabismus. (stuck medially is an abysmal situation-damn near rect'us)
diplopia double vision
what part of the tongue is the salivatory nucleus responsible for and what cranial nerve is it a part of? the Inferior Salivatory Nucleus of the Glossopharyngeal CN9 is the posterior 1/3 of tongue BITTER taste
what 3 nuclei are associated with Glossopharyngeal CN9 Inferior Solitary Nucleus (7.9.10 -I was alone when I 8 it)for BITTER post 1/3 tongue, Nucleus AMbiguus (9-11) so stylopharyngeus can't swallow and dysphonia/dysphagia/uvula deviation, Inferior Salivatory Nucleus is PAROTID salivary,& Carotid sinus (+-)
Fovea of one eye corresponds to the fovea of the other, images falling on the two foveas are 'projected' to the same point in space. Misaligned,brain will 'project' two different images in the same visual direction. This phenomenon is known as 'Confusion' DIPLOPIA
a lesion of the Abducens 6 diplopia (double vision) and medial strabismus (stuck medially because lateral rectus muscle is flaccid paralysis)
insults to the Trigeminal nerve seem to be from doinking your head on a cabinent, blowing your nose too hard, biting your tongue, getting a migraine = all "internal" pains. What nerve is responsible for your "external" face, like expressions? FAcial nerve 7 (lucky face)
why is the Nucleus of the Solitary Tract involved with the facial nerve (remember it started at middle medulla and is involved in lateral medullary syndrome) Solitary tract and Nucleus receives TASTE fibers from 7.9.10 (I was alone when I 8 it) so Lucky 7 is FACIAL nerve that originates at lower pons level of facial colliculus
Nucleus of Solitary tract (from lower pons at facial colliculus level) is for what two things? taste and parasympathetic (7.9.10)
Two origins/nuclei of FACIAL 7 Facial nucleus & Solitary Nucleus & Superior Salivatory nucleus (you've got a lucky FSS!)
Taste isn't motor - what is it and what is it's origin? Solitary nucleus at middle medulla (mid-olive)is taste and parasmpathetic
Inferior Salivatory nucleus belongs to what nerve? Glossopharyngeal glands
Superior Salivatory nucleus belongs to what nerve? Facial glands
where is the facial motor nucleus behind the facial colliculus above cerebellopontine angle so we know the facial nerve originates at the lower pons
where is the nucleus of solitary tract? (7.9.10) mid medulla:between the Dorsal Motor Nucleus of VAgus and the Four Vestibular Nuclei that project to cord, cerebellum and MLF. Upper medulla:between Four Vestibulocochlear nuclei and Spinal tract/nucleus of Trigemninal, and MCpeduncles are lateral to it.
What is the Superior Salivatory Nucleus? FACIAL GLANDS parasympathetics
the superior salivatory nucleus is an autonomic nucleus providing _____________fibers to the facial nerve, and is affiliated with pterygopalatine and submandibular ganglia. parasympathetic (GLANDS)
Two Zebras Bit My Cat Temporal, Zygomatic, Buccal, Marginal mandibular, Cervical (branches of facial nerve 7)
the facial nerve is motor to muscles of facial expression (motor nucleus at lower pons behind facial colliculus)
the facial nerve is sensory to anterior 2/3 tongue via chorda tympani (nucleus of solitary tract 7.9.10 involvement of TASTE)
the facial nerve is parasympathetic to lacrimal and serous and mucous glands of nasopharynx -the hayfever branch!- submandibular, and sublingual glands (Superior Salivatory nucleus FACIAL GLANDS)
Nucleus of Solitary tract: Taste 7.9.10 (I was ALONE when I 8 it)therefore TASTE
Superior Salivatory Nucleus FACIAL GLANDS
Inferior Salivatory Nucleus GLOSSOPHARYNGEAL GLANDS
taste to posterior 1/3 bitter tongue solitary nucleus and tract (7.9.10)
taste to anterior 2/3 tongue solitary nucleus and tract (7.9.10)
let's move on, shall we? yes, let's.
the FACIAL nerve 7 is responsible for (exam only) facial expression and taste
lesion to FACIAL 7 BELL's Palsy
Bell's Palsy LOWER motor neuron (because it's a cranial nerve, it's LMN - if it were an UMN and the motor message hadn't crossed yet, it would be contralateral to lower 1/4 quadrant. Since LMN, it HAS crossed and flaccid paralysis to whole ipsilateral side of face)
what are some symptoms of the LMN Facial nerve lesion BELL's Palsy? LMN flaccid paralysis to ipsi face half/hyperacousis, cannot wrinkle forehead, raise eyebrow, shut eye, smile, tear flow over sagging eyelid, loss of taste from anterior 2/3 of tongue
tears running out of lower eyelid, no taste to anterior 2/3 tongue, can't smile, can't raise eyebrows or even shut eyes! What is this? Bell's Palsy -LMN ipsilateral facial paralysis due to fACIAL 7 lesion
what part of brainstem is Facial nerve associated with? Pons (lower pons at facial colliculus)
VESTIBULOCOCHLEAR nerve 8 is disscussed with nerves associated with the medulla (where the four vestibular nuclei and and dorsal cochlear nucleus orginate)
where are the cochlear nuclei deep to acoustic tubercle at the upper medulla level. They are at the butterfly wing before the vestibulocochlear nerve pops out lateral most side)
where are the four vestibular nuclei (that turn to three, etc. as we go upwards in the sections) vestibular area of both medullary and pontine floor of 4th ventricle - they start in middle medulla at mid-olive level and go up to lower pons at level of facial colliculus. Basically they are on either side of the 50yd line-striae medullaris to Magendie
are the vestibulocochler nuclei pontine or medullary? four vestibular are both, cochlear are medullary only at acoustic tubercle
function of vestibulocochlear? balance, equilibrium, hearing
lesion to vestibulocochlear? vertigo, vomiting, vertical nystagmus, loss of hearing
2 areas of MIDBRAIN 1. TECTUM: everything from inferior/superior colliculi to middle of aqueduct2.CEREBRAL PEDUNCLE: whatever is anterior to aqueduct (tegmentum of midbrain, substantia nigra, crus cerebri)
see slides before you begin midbrain there are only 2 slides. Go ahead - I know you are tired...
what is the area of midbrain anterior to cerebral aqueduct called cerebral peduncle (right above the basilar pons)
what lies posterior to the cerebral aqueduct of the midbrain? tectum of midbrain
what lies posterior to the basilar pons? tegmentum of pons
what lies posterior to the cerebral aqueduct of midbrain? tegmentum of midbrain
the grey matter around the aqueduct of midbrain periaqueductal grey (PAG)
what excites the PAG? enkephalins and other opiates (endogenous morphines=endorphins)
when excited by enkephalins and opiates, the periaqueductal grey, in turn, excites the __________ & the ____________ Raphe Nuclei of the RETICULAR formation (Wake up!) & the Locus Coeruleus (noradrenergic nucleus that shuts off during REM sleep)
the Raphe Nuclei of the Reticular Formation make what and are excited by what? makes serotonin (5-HT) and is excited by Periaqueductal Grey
the Locus Coeruleus of upper pons makes and does what? NE and shuts off during REM
at what level is the Locus Coeruleus first seen and what does it do and who excites it? first seen at MidPons at corner of 4th ventricle, makes Norephinephrine/noradrenaline, excited by Periaqueductal grey (that was stimulated by enkephalins/opiates at lower midbrain level)
at what level does Raphe Nucleus appear? Does what? Excited by... appears at lower midbrain, makes serotonin, excited by PAG (enkephalins and opiates)
what is an endogenous morphine/endorphin/enkephalin doing for you? stopping pain messages at the level of Nucleus proprius in the dorsal horn from transmitting pain
the tectum holds two superior and two inferior colliculi that are collectively referred to as Corpora Quadrigemina
the INFERIOR COLLICULUS is involved in hearing
From where do afferents come to the Inferior Colliculus of the tectum of midbrain? Lateral Lemniscus
where is the lateral lemniscus? in the tegmentum of the lower pons, carrying fibers upward to the inferior colliculus
Lateral lemniscus at tegmentum of lower pons to inferior colliculus to? inferior brachium to medial geniculate body (auditory)
which geniculate body is associated with inferior brachium, inferior colliculus, and lateral lemniscus? MEDIAL
The superior colliculus gets its afferent cues from the optic tract (taking in light)
Optic tract to Superior Brachium to Superior Colliculus to (efferents) to Edinger-Westphal nucleus for pupillary constriction
what does the Edinger-Westphal nucleus do with efferent information from superior colliculus? sends efferents to pupillary muscles to CONSTRICT or dialate
Edinger-Westphal nucleus pupillary constriction
the inferior colliculus and superior colliculus receive information from the inferior brachium and superior brachium (t/f?) FALSE. The inferior colliculus does efferent to inferior brachium to medial geniculate body, but the superior colliculus RECEIVES (afferents) information from the optic tract via the superior brachium, and then it sends efferents to Edinger-Westphal.
inferior colliculus OUT to inferior brachium, superior brachium IN to superior colliculus (t/f?) True.
3 structures of Cerebral Peduncle of Midbrain tegementum of midbrain, substantia nigra, crus cerebri
space between the two cerebral peduncles (crus cerebri) is the interpeduncular fossa
what's in the interpeduncular fossa? Posterior perforated substance
structure in tegmentum of midbrain at inferior colliculus level? Decussation of Superior Cerebellar Peduncles (think -right past lingula and superior medullary vellum)
What is inside the Decussation of the Superior Cerebellar Peduncles at the level of inferior colliculus of midbrain? the ventral spinocerebellar tract enters the cerebellum in the superior cerebellar peduncles, and the dentate nucleus of cerebellum sends fibers to the decussation of the superior cerebellar peduncles
after fibers ascend from DENTATE NUCLEUS of cerebellum, cross the DECUSSATION OF THE SUPERIOR CEREBELLAR PEDUNCLES, they go to the RED NUCLEUS
dentate nucleus to decussation of superior cerebellar peduncles to red nucleus at superior colliculus level of midbrain
if you see the Decussation of the Superior Cerebellar Peduncles (a white bundle of fibers just medial and posterior to substantia nigra in crus cerebri), what level of midbrain? level of inferior colliculus = decussation of superior cerebellar peduncles
what do we see at the level of the superior colliculus (optic tract to superior brachium to s. colliculus to Edinger-Westphal n. to pupillary constrict) level of superior colliculus = RED nucleus
superior colliculus is relates optic so what looks like Mickey Mouse's eyes at the level of superior colliculus? red nuclei
what is afferent to red nucleus? fibers sent by dentate nucleus of cerebellum that crossed below at the decussation of superior cerebellar peduncle and are now headed to red nucleus
2 divisions of substantia nigra 1. Pars compacta2. Pars reticulata
Pars compacta of substantia nigra (midbrain) DA for basal ganglia/ motion and addictive behavior (cocaine, dopamine, frenetic movement)
part of substantia nigra associated with dopamine, addiction, and movement Pars compacta (most lateral)
Pars reticulata of substantia nigra GABA, motion
medial part of substantia nigra that is a GABAergic nucleus of basal ganglia involved in motion Pars reticulata
the pars reticulata is a culprit in Parkinson's and epilepsy. GABA is an inhibitor. The pars reticulata of s.n. lets you retain/reticulate control (reticular is a network, although a loosely arranged one, like retinaculum for ligaments and reticular formation of medulla)
pars compacta neurotransmitter dopamine (DA)
pars reticulara neurotransmitter GABA
pathological changes in substantia nigra (pars compacta and reticulara) are seen in what presentations? Parkinson's, schizophrenia (basal ganglia)
what structures are most ventral in the midbrain? crus cerebri
contents of CRUS CEREBRI cortico-spinal fibers in medial 3/5 (UMN motors to ventral horn nuclei), and temporo- and fronto-pontine fibers on their way to pontine nuclei
where do pontine nuclei send fibers? to cerebellum via middle cerebellar peduncles
where do frontopontine and temperopontine fibers travel in the midbrain in the medial and lateral fifths of the crus cerebri
Majority of fibers in crus cerebri of midbrain corticospinal fibers on way through pons then pyramids, then decussation then 85% distal (but 15% ipsilateral don't cross and go to core)
Parkinson's is too little ________ from pars compacta dopamine
___________ is too much DA from pars compacta schizophrenia
Dorsal to cerebral aqueduct is the tectum of midbrain
what nerve is associated with the tectum of the midbrain? TROCHLEAR 4
why is the TROCHLEAR 4 different from all the other cranial nerves? it crosses inside the midbrain, so it's effects are contralateral to the nucleus/nerve
where does the TROCHLEAR 4 nerve cross? superior medullary vellum
what collicular level is TROCHLEAR 4 associated with? inferior colliculus (and therefore decussation of superior cerebellar peduncles)
TROCHLEAR 4 exit? INFERIOR to inferior colliculus, after decussating in the superior medullary vellum
function of TROCHLEAR 4 SO4: superior oblique extraocular eye muscle that turns eye down and in (going down stairs)
lesion to TROCHLEAR 4 inability to look down and in (SO4 ruined)
(LR6, SO4)3 SO4 is cranial nerve 4 trochlear contralateral superior oblique down and in
if you injure/lesion the left trochlear nuclei, you get right trochlear trouble (SO4)
see the University of Toronto's extraocular muscles superior view page (LR6 SO4)3
where is the superior oblique muscle (SO4) with pulley is medial top of eye but pulls eye down and in
OCULOMOTOR nerve controls (LR6, SO4)3 so III OCULOMOTOR is all other eye muscles except lateral rectus and superior oblique
nucleus of Oculomotor 3 anterior portion of periaqueductal grey at superior colliculus level
the periaqueductal grey looks like a heart, apex to anterior/ventral. What comes out of apex at inferior collicular level? at superior collicular level? PAG @ inferior colliculus = TROCHLEAR 4PAG @ superior colliculus = OCULOMOTOR 3
exit of OCULOMOTOR 3 interpeduncular fossa: in the perforated substance of interpeduncular fossa at superior colliculus level
muscles of eye for oculomotor 3 (five) medial rectus, superior rectus, inferior rectus, Internal oblique, levator palpebrae superioris
the oculuomotor nerve, besides responsible for all eye muscles except LR6 & SO4, also sends parasympathetics to SPHINCTER PUPILLAE for constriction
a lesion to the oculomotor nerve will affect pupil constriction (sphincter pupillae) so pupils will be dialated!
Lesion to OCULOMOTOR 3 ptosis (droopy eyelid), lateral strabismus (Medial rectus gone), mydriasis (enlarged, unresponsive to light, pupil), cycloplegia (enlarged, unresponsive to accomodation, pupil)
ptosis droopy eyelid
lateral strabismus medial rectus wrecked
mydriasis enlarged, unresponsive to light, pupil (Aubrey)-
cycloplegia enlarged, unresponsive to ACCOMODATION pupil
it's always midday sun for mydriasis! mydriasis - enlarged pupil unresponsive to light
cyclops cannot focus and will not accomodate you cycloplegia - ciliaris affected, cannot change near to far focus, etc.
why is the lateral lemniscus gone at superior colliculus level of midbrain? its auditory fibers from the cochlear system already went to the inferior colliculus and then out the inferior brachium to the Medial Geniculate Body (then thalamus)
the CEREBELLUM makes up _____ the volume of the brain! 1/10
What percentage of the cells of the CNS are contained in the cerebellum (the 1/10!) 1/2! So half of all the cells in the entire CNS are contained in the cerebellum.
Most of the tracts bring information ______ the cerebellum. INTO
Functions of cerebellum 1-fine tuning of movement2-motor learning
fine tuning of movement inside cerebellum is excitation and inhibition of TIMING of muscle sequences
motor learning of movement inside cerebellum is improved by seeing or imagining/visualizing the action
the Cerebellum is made up of 2 hemispheres and a vermis
2 hemispheres and a vermis walk into a bar. The vermis had to break up the two hemispheres of the cerebellum
the vermis is a __________structure that separates the two cerebellar ___________. midline, hemispheres
there are ___lobes of the cerebellum 3
name the 3 lobes of cerebellum anterior, posterior, flocculo-nodular
what separates the anterior from the posterior lobe of cerebellum? PRIMARY FISSURE
What fissure is right above the nodule and flocculus, separating the giant posterior lobe from the little flocculo-nodular lobe? DORSOLATERAL FISSURE
2 divisions of Vermis of cerebellum superior vermis, inferior vermis
What divides the vermis into superior and inferior divisions? posterior border of TONSIL
which is longer, the superior vermis or inferior vermis and why? superior is much longer - the tonsils are rather short on the inferior/underside of the cerebellum and inferior vermis is only as long as the tonsil on each side of it.
the cerebellum is connected to the superior medullary vellum via the lingula (and by the peduncles, of course). To what part of vermis does lingula belong? superior (from lingula to tonsil tops is the superior vermis)
the flocculo-nodular lobe (nodule and flocculus) is associated with what part of vermis? inferior vermis is what separates the flocculo-nodular lobe from the giant posterior lobe.
describe the 3 cerebellar peduncles: superior c.p. from midbrain, middle c.p. from pons, inferior c.p. from medulla
there are ____ deep cerebellar nuclei. 4
Spasticity:lesion of one pyramidal tract. Loss of the inhibitory effect of the corticospinal pathway increases the spinal reflex activity of the gamma-loop. (interesting definition of why spasticity causes flexion) flip card. The muscle tone is increased towards rapid, passive movements of the limbs-sudden clasp-knife effect.
How will you remember the 4 deep cerebellar nuclei if you don't see them in situ. Please see slides. They are cool - from an MRI neuroimaging project at Vanderbilt Engineering School.
Name the 4 cerebellar nuclei dentate, emboliform, globose, fastigial
which cerebellar nucleus sounds like "fast" and "vestigial" fastigial
which cerebellar nucleus sounds like "embolus" emboliform
which cerebellar nucleus sounds like "glob" globose
which cerebellar nucleus means "tooth" dentate
name the 4 cerebellar nuclei dentate, globose, emboliform, fastigial
Three layers of cerebellar cortex: molecular, Purkinje fibers, granular
which layer of cerebellar cortex contains the fewest type of cells? Purkinje cells, the ONLY type at the middle cerebellar cortex layer (Purkinje layer)
The first and deepest layer of the cerebellar cortex is GRANULAR layer: the "dirt" of the three layers, contains granules and Golgi's.
what does the deepest "dirt" layer of the cerebellar cortex contain? GRANULAR layer contains granule and Golgi cell bodies
Granular layer of cerebellar cortex is at the border to the white substance and is characterized by densely arranged, __________neurons with little plasma. multipolar
what are the multipolar neurons of the granular cerebellar cortex? Granular and Golgi cells
the middle layer of the cerebellar cortex Purkinje cells
what do Purkinje cells have that the pars reticulata of the substantia nigra also makes (basal ganglia involved in motion)? GABA. The Purkinje's also make glycine. Both GABA & glycine are inhibitory to motion.
Can the Purkinje cells of the middle cerebellar Purkinje layer excite? Why or why not? NO, they contain only inhibitory neurotransmitters: GABA and Glycine
Outermost layer of cerebellar cortex Molecular layer
the Molecular layer contains what cells? cell bodies of BASKET and STELLATE cells, axons of Granule cells that form parallel fibers, and dendrites of Purkinje cells.
Yeah, you got that molecular layer down? Here's how: look at picture of cerebellar layers. What differences can you SEE between the 3 layers? Bottom layer is dense! Bottom layer is all dirt (goli and granular). Purkinje layer is only trunk (cell body) of Purkinje tree. Molecular is basket-& stellate-shaped leaves, Purkinje branches/dendrites & dirty axons from ground.
what shapes are the "leaves" in the molecular layer? Basket and stellate shaped
where do the "branches" (dendrites) in the molecular (atmospheric) layer come from? Purkinje "trunk" cell bodies in the Purkinje layer
how would "dirt" from the granular layer get to the molecular layer? granular axons, like the (xylem and phloem of a tree) have to travel all the way from the ground to the tips of branches.
describe 3 cerebellar cortex layers: GRANULAR=dirt (golgi and granular cell bodies) PURKINJE=tree root (cell bodies of Purkinje cells, GABA & glycine-movement inhibition) MOLECULAR=sky (dendrites Purkinje cell bodies, granular axons/parallel fibers, basket & stellate shaped cell bodies
what kind of cells are Purkinje roots? multipolar
How many synapses can one Purkinje cell body receive? 1 million
which cells have the most power in the cerebellum layers to influence dealings outside the cerebellum? Purkinje are the ONLY output cells of the cerebellar cortex to the rest of body.
Purkinje cells (roots) inhibit the deep cerebellar _______ that project out of the cerebellum (and others) nuclei (4)
name the deep cerebellar nuclei that are inhibited by Purkinje output Dentate, Emboliform, Globose, Fastigial
what is the point of inhibition via Purkinje output (GABA/glycine)? tells you how to make motion in order to be smooth
at what level is the inferior olivary nucleus? middle medulla to upper medulla
what fibers at the upper medulla (pontomedullary junction -"butterfly" cross-section)are axons involved in motor control from the inferior olivary nucleus coursing to the contralateral cerebellum? Olivo-cerebellar fibers
________ _________originate from the inferior olivary nucleus. While they were called olivo-cerebellar fibers that crossed in the medulla, now that they are in the cerebellum, what are they called? CLIMBING FIBERS
what cerebral peduncle does medulla use to communicate with the cerebellum? Inferior cerebellar peduncle
what peduncle would you guess the old olivo-cerebellar cum Climbing fibers use to enter the cerebellum after they cross in the medulla from the inferior olivary nucleus? Inferior cerebellar peduncle
Don't all fibers that enter the cerebellar peduncle "climb" up from the lower parts of the body? yes, so CLIMBING FIBERS originating from the inferior olivary nucleus (olivo-cerebellar fibers) makes sense.
Climbing fibers originate from the inferior olivary nucleus so they relay ________ and __________ information. Sensory and visual
Climbing fibers relaying sensory and visual from inferior cerebellar peduncle/inf. olivary nucleus excite what? deep cerebellar nuclei (4) & Purkinje cells
climbing fibers excite deep cerebellar nuclei & Purkinje cells
what kind of fibers originate from the spinal cord and brainstem nuclei, so they relay peripheral information to the cerebellum? MOSSY fibers.
why is it easy to remember mossy fibers go to granular layer/granular cells? Moss grows on dirt/granules.
Mossy fibers excite deep cerebellar nuclei and granular cells.
class diagram shows mossy fibers only going to granular cells, but power point and lecture notes say they go to granular & deep cerebellar nuclei. We are going with the latter. see slide for this studystack
Mossy fibers excite:Climbing fibers (from ION) excite:Purkinje inhibits: Mossy fibers (peripheral info) excite deep cerebellar nuclei and granular cells (moss on dirt). Climbing fibers (ION) for sensory/visual excite deep cerebellar nuclei and Purkinje. Purkinje inhibit deep cerebellar nuclei, always.
what is the ONLY output of the cerebellar CORTEX Purkinje Inhibition (via deep cerebellar nuclei)
why is the only way for Purkinje to inhibit via the deep cerebellar nuclei? these 4 nuclei have projections OUT of the cerebellum (the only way out)
In summary, deep cerebellar nuclei receive ________ impulses from mossy (peripheral) fibers and _______impulses from climbing (sense/visual) fibers and ____________impulses from Purkinje cells. Mossy + Climbing EXCITE to deep cerebellar nuclei. Purkinje INHIBIT to deep cerebellar nuclei.
3 functional divisions of cerebellum 1-flocculonodular lobe + vermis + fastigial nucleus2-medial cerebellar hemisphere (MCH)3-lateral cerebellar hemisphere (LCH)
the vermis + fastigial nucleus are a part of the flocculo-nodular lobe
why does it make sense for the vermis to be included with the fastigial nucleus and flocculonodular lobe? they are all most medial
another name for flocculo-nodular lobe vestibulocerebellum
what cerebellar lobe suffers when you consume alcohol and when lesioned, mimics the effect of alcohol on balance and coordination? vestibulocerebellum/flocculo-nodular lobe
flocculo-nodular lobe (vestibulocerebellum) projects to the _________ nuclei of the middle medulla through lower pons level. vestibular nuclei
which can affect vestibular nuclei: medial medullary syndrome or lateral medullary syndrome? lateral medullary syndrome ( dissociated sensory loss -one side of body, other side of face). Can also affect cerebellar connections.
lateral medullary syndrome might affect the cerebellum flocculonodular lobe because four vestibular nuclei/projections from medulla that go to vestibulocerebellum/flocculo-nodular may be affected
function of flocculo-nodular/vestibulocerebellar lobe? Balance and Eye movement
the Vermis affects trunk, head, neck movements
Remember we said nuclei were the only way OUT of the cerebellum, after they had synapsed with mossy, climbing and Purkinje fibers? What nucleus would get messages from flocculonodular lobe and vermis? FASTIGIAL
the FASTIGIAL nucleus projects to the medial descending system that controls the proximal muscles of the body and limbs. How are you going to remember that? FASTIGIAL- the archicerebellum is the flocculonodular lobe and vermis, the Oldest part of the cerebellum. It is a vesTIGAL part of cerebellum. Get drunk or lesion it, you'd better hold FAST to something or you'll fall! (I'm just floccing with you).
Afferent (IN) to flocculonodular lobe: vestibular fibers with info about HEAD motion, GRAVITY relativity, and Superior Colliculus (eye) and Occipital lobe (eye) visual reflexes.
The Vermis receives VisualAuditoryVestibular &Spinal Sensory
efferents of flocculonodular lobe projects to vestibular nuclei for control of eye movements and Hand-eye coordination
bothe the flocculonodular lobe and the vermis via the FASTIGIAL nucleus project to the medial descending system that controls the PROXIMAL MUSCLES OF BODY and limbs
why would flocculonodular lobe and vermis projecting to Medial descending system control proximal body and limb muscles it's medial. Flocculonodular, vermis, fastigial nucleus, and medial descending system are all MEDIAL - together!
lesion flocculonodular lobe truncal axtaxia + incoordination due to impared used of visual cues. Unable to perform tandem gait. May fall with eyes open or closed during Rombergs.
flocculonodular lobe + vermis + fastigial lesion: truncal ataxia, no tandem gait, fall Romberg's test
Medial cerebellar hemispheres include the tonsil
Medial cerebellar hemispheres + tonsil use what 2 nuclei? globose and emboliform nuclei
globose and emboliform nuclei area associated with what 2 cerebellar structures medial cerebellar hemispheres and tonsils
Medial cerebellar hemispheres, tonsils and globus and emboliform nuclei function in Posture & Locomotion: He sat straight up in bed after the tonsilectomy and said, "Let's get outta here!"
the medial cerebellar hemispheres receive afferents from the limbs (locomotion)
the medial cerebellar hemispheres send information to the lateral descending system via the globose and emboliform nuclei
lesion to medial cerebellar hemispheres (globose, emboliform, tonsils) He sat straight up in bed after the tonsilectomy and said, "Let's go", but he had a lesion so...hypotonia, pendular reflexes, scanning speech, appendicular ataxia via dysmetria, ataxic joint motion, and intention tremor stopped him. Whew!
hypotonia decreased muscle tone
pendular reflexes ?
scanning speech ?
appendicular ataxia exhibited by dysmetria and ataxic joint motion inability to judge distance which results in over or undershooting
what area of the neuron propagates the action potential? conducting zone
intention tremor gross tremor that appears at rest
in a lesion to the flocculonodular lobe + vermis + fastgial nucleus, the visual system is not compeletely ruined but what does suffer? motor system
cerebellar patients can have a ________dysfunction or they can have the demyelinating disease that loves the cerebellum, _____________________. genetic, Multiple Sclerosis
what's the difference between MS and ALS? Multiple sclerosis is spastic paralysis (UMN lesion of flocculonodular/medial/lateral cerebellar hemispheres) whereas ALS is ONLY MOTOR so pure weakness.
ALS is purely motor.
the purely motor demyelinating disease (of both upper and lower motor neurons, no sensory) is ALS
sum up lesion to medial cerebellar hemisphere with tonsils and globose and emboliform: Posture and Locomotion: appendicular ataxia with dysmetria, intention tremor, no control of distal limb muscles
Lateral cerebellar hemispheres - there's only one nucleus left and it's a doozy. What is this most lateral nucleus? Dentate
the Dentate nucleus project for the Lateral Cerebellar Hemispheres
Lateral CEREBELLAR hemispheres and dENTATE nucleus function in planning of complex actions, conscious assessing of movements, and perceptual cognitive functions.
why does it make sense for the DENTATE nucleus to be involved in planning complicated actions and sequences, assessing movement consciously, and preceptual cognitive functions? because the DENTATE is the biggest of the 4 deep cerebellar nuclei
Afferents from the lateral cerebellar hemispheres receive information from the cortex of the brain via the PONTINE nuclei (the largest part of the brainstem sends complicated conscious assessment info to the largest cerebellar nucleus)
where do the lateral cerebellar hemispheres get their information about planning complex actions, conscious assessing of movements, and perceptual cognitive functions? the pontine nuclei (via cortex)
what level of the midbrain does red nucleus live? superior colliculus, at end of medial lemniscus and mesencephalic nucleus
Superior cerebellar fibers from the lateral cerebellar hemispheres leave their door - the dentate nucleus, and then what? from dentate, they ascend into superior cerebellar peduncles, cross, and arrive in the RED NUCLEUS. The RN goes to inferior olivary nucleus (motor control)
INstead of the dentate projections ascending to superior cerebellar peduncles, crossing, then going to Red Nucleus then Iferior Olivary Nucleus, what could they do? bypass the red nucleus and end in the thalmus and eventually the premotor cortex (for more planning, one assumes)
what are the two destinations of information from the lateral cerebellar hemispheres after dentate nucleus? red nucleus to inferior olivary nucleus OR thalamus to premotor cortex
when you have a basal ganglia disorder, like Parkinson's, your movement is uneven, uncertain, etc. If you had a lesion to the lateral cerebellar hemispheres and dentate nucleus, so no motor planning and assessment, what would you look like? you'd have to think of every movement you took for granted, your movements would be decomposed, you'd have truncal ataxia with irregular movements, and dysdiadocho-kinesia (couldn't do rapid alternating movements).
dentato-rubro-thalamic tract is probably involved in what? planning movement then controlling it -joins basal ganglia
if my dopamine levels were too low due to some glitch in the basal ganglia (substantia nigra's pars compacta), and my dentato-rubro-thalamic tract is off, what's wrong with me? lateral hemisphere/dentate lesion or substantia nigra problem means decomposition of movements, having to think of "subconscious movement," TRUNCAL ataxia as evidenced by DYSRHYTHMIA, and DYSDIADOCHOKINESIA
dysdiadochokinesia inability to perfom rapid, alternating movements
DDK (from Greek dys "bad", dia "across", docho "receive", kinesia "movement") is the medical term for an inability to perform rapid, alternating movements. dys dia docho kinesia = bad across receive movement (unable to toss a ball back and forth between hands). Symptom of lesion to lateral cerebellar hemispheres/dentatorubrothalamic tract -mostly DENTATE is DYSDIADOCHOKINESIA
dentate is (lesion) disdiadochokinesia
In animals without a significant corticospinal tract, gait is mainly controlled by the red nucleus. the crawling of babies is controlled by the red nucleus, as is arm-swinging in normal walking.
The red nucleus receives many inputs from the contralateral cerebellum (interposed nucleus and lateral cerebellar nucleus) and an input from the ipsilateral motor cortex The majority of red nucleus axons do not project to the spinal cord, but instead relay information from the motor cortex to the cerebellum through the inferior olivary complex- an important relay center in the medulla
The red nucleus receives many inputs from ____________ cerebellum, and input from the ___________ motor cortex. Contralateral cerebellum (crossed at superior cerebellar peduncle from dentate), Ipsilateral motor cortex
astrocytes restrict spread of neurotransmitters & REGULATE the concetration of POTASSIUM (PotASStrocytes!)
the conductile component is the area responsible for propagating an action potential (ITCO)
the amount of neurtransmitter released by the output zone is dependent on the number and frequency of action potentials
where is the all or none action potential GENERATED Trigger/spike zone
one process that gives rise to many branches unipolar
two processes, a dendrite and an axon bipolar
two processes, both function as axons pseudounipolar (DRG have a central and peripheral axon)
an axon and many dendrites multipolar
what zone is covered by myelin sheaths conduction
the diameter of a pore determines ion selectivity
4 types of gates ligand, P, voltage, mechanical
a voltage gated channel requires a change in equilibrium
resting membrane potential is determined by non-gated ion channels (because they are always open)
how does the Na+/K+ pump expend the cells energy? it needs to be re-phosphorylated at every cycle
3 Na+ out for every 2 K+ in
Na+, Cl-, Ca++ are outside
______________is the number of open channels permeability
what is the threshold number for our class -40mV
K+ gates open at -1. Are both Na+ and K+ open during overshoot? when does Na+ close? yes, Na+ then locks until a minus value is reached
Are potassium and sodium gates open at same time? When does Na+ close? WHen is Na/K pump active? They are open at the same time in overshoot until Na+ closes at -1. K+ is open during Na+’s closing phase.Na/K pump is active through entire phase.
AT THRESHOLD, BOTH ARE OPEN: Na is responsible for rising phase, K is responsible for falling phase. These phases are also called overshoot (Na+) and undershoot (K+)
Synaptic vesicles fuse with the inner surface of the presynaptic membrane at sites called active zones
Release of neurotransmitters depends on ________ influx and occurs by ___________ CALCIUM, exocytosis
__________________ are also found in the presynaptic membrane; they function in inhibiting further neurotransmitter release or stimulating neurotransmitter synthesis. metabotropic receptors
primary excitatory neurotransmitter in CNS glutamate
spinal cord inhibitory neurons have glycine
CNS inhibitory neuron GABA
Is the “input zone” of a neuron after a synapse. Contains neurotransmitter receptors in sites called postsynaptic densities. It transmits a “synaptic potential” which is the sum of the incoming EPSPs and IPSPs. postsnyaptic membrane
what are postsynaptic densities where postsynaptic membranes keep NT's
agonist for non-NMDA/AMPA-kinate receptors CNQX
NMDA receptors (receptor sites for Gly, Mg++, Zn++, PCP; allows influx of Ca++; implicated with cell death resulting from haemorrhagic stroke, epilepsy, and Huntington’s chorea) ANTAGONIST? APV
Created by: Heather Cutler Heather Cutler on 2010-02-24



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