21-spinal cord tracts i
TRANSCRIPT
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Sensory & MotorSensory & Motor
PathwaysPathways
Dr. Zeenat ZaidiDr. Zeenat Zaidi
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There is a continuous flow of information between theThere is a continuous flow of information between the
brain, spinal cord, and peripheral nerves.brain, spinal cord, and peripheral nerves. ThisThis
information is relayed by sensory (ascending) andinformation is relayed by sensory (ascending) andmotor (descending) pathways.motor (descending) pathways.
Generally the pathways:Generally the pathways:
onsists of a chain ofonsists of a chain of tracts,tracts,associatedassociated nucleinucleiandand
varying number of relays (varying number of relays (synapsessynapses)) onsist of two or three neuronsonsist of two or three neurons
!"hibit somatotopy (precise spatial relationships)!"hibit somatotopy (precise spatial relationships)
#ecussate#ecussate
$nvolve both the brain and spinal cord$nvolve both the brain and spinal cord
%re paired (bilaterally and symmetrically)%re paired (bilaterally and symmetrically)
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Somatic Sensory PathwaysSomatic Sensory Pathways
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Sensory Pathways
&onitor conditions both inside the body and in the&onitor conditions both inside the body and in thee"ternal environmente"ternal environment 'ensationstimulated receptor passes information to'ensationstimulated receptor passes information to
the ' via afferent (sensory) fibersthe ' via afferent (sensory) fibers
&ost sensory information is processed in the spinal&ost sensory information is processed in the spinalcord , thalamus, or brain stem. *nly + reaches thecord , thalamus, or brain stem. *nly + reaches thecerebral corte" and our conscious awarenesscerebral corte" and our conscious awareness
-rocessing in the spinal cord can produce a rapid-rocessing in the spinal cord can produce a rapid
motor response (stretch refle")motor response (stretch refle") -rocessing within the brain stem may result in-rocessing within the brain stem may result in
comple" motor activities (positional changes in thecomple" motor activities (positional changes in theeye, head, trun)eye, head, trun)
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Sensory Pathways ontain a se/uence ofontain a se/uence of T01!!T01!!
neuronsneuronsfrom the receptor to thefrom the receptor to thecerebral corte"cerebral corte" First order neuron:First order neuron: 'ensory'ensory
neuron that delivers informationneuron that delivers informationfrom the receptor to the '.from the receptor to the '.
ell body located in the dorsalell body located in the dorsalroot ganglion. The %"on (centralroot ganglion. The %"on (centralprocess)process) passes to the spinalpasses to the spinalcord through the dorsal root ofcord through the dorsal root ofspinal nervespinal nervegives manygives manycollaterals which tae part incollaterals which tae part inspinal cord refle"esspinal cord refle"esrunsrunsipsilaterallyipsilaterallyand synapses withand synapses withsecondorder neurons in thesecondorder neurons in thecord and medulla oblongatacord and medulla oblongata
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'econd order neuron:'econd order neuron: 0as cell body in the0as cell body in the
spinal cord or medullaspinal cord or medullaoblongataoblongata%"on decussate%"on decussate 22 Terminate on 3rd orderTerminate on 3rd order
neuronneuron
Third order neuron:Third order neuron: 0as cell body in0as cell body in
thalamusthalamus%"on terminates on%"on terminates on
cerebral corte"cerebral corte"ipsilaterallyipsilaterally
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White Matter: PathwayWhite Matter: Pathway
GeneralizationsGeneralizations
%scending and descending fibers are organi4ed in%scending and descending fibers are organi4ed indistinct bundles which occupy particular areas anddistinct bundles which occupy particular areas and
regions in the white matterregions in the white matter
GenerallyGenerally long tractslong tracts are located peripherally in the whiteare located peripherally in the white
matter, whilematter, while shorter tractsshorter tracts are found near the grayare found near the gray
mattermatter
5 The TRACTis a bundle of nerve fibers (within ')
having the same origin, course, destination 2
function5 The name of the tract indicates the origin and
destination of its fibers
5 The a"ons within each tract are grouped according
to the body region innervated
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Tracts of the SpinalTracts of the Spinal
CordCord
Tracts that serve to 6oin brain to the spinalTracts that serve to 6oin brain to the spinalcordcord %scending%scending #escending#escending
7ibers that interconnect ad6acent or distant7ibers that interconnect ad6acent or distantsegments of the spinal cordsegments of the spinal cord $ntersegmental$ntersegmental(propriospinal)(propriospinal)
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nterse!mental Tractsnterse!mental Tracts !"tensive fiber connections!"tensive fiber connections
between spinal segmentsbetween spinal segments Fasciculus propriusFasciculus proprius
'hort ascending 2'hort ascending 2descending fibersdescending fibers
8oth crossed 28oth crossed 2uncrosseduncrossed 8egin and end within the8egin and end within the
spinal cordspinal cord -articipate in-articipate in
intersegmental spinalintersegmental spinalrefle"esrefle"es
-resent in all funiculi-resent in all funiculiad6acent to gray matterad6acent to gray matter
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Intersegmental Tracts Dorsolateral tract ofDorsolateral tract of
Lissauer:Lissauer: -rimary sensory-rimary sensoryfibers carryingfibers carrying pain,pain,
temperature and touchtemperature and touch
information bifurcate uponinformation bifurcate upon
entering the spinal cord. Theirentering the spinal cord. Their
branches ascend and descendbranches ascend and descendfor several spinal segments infor several spinal segments in
the dorsolateral tract, beforethe dorsolateral tract, before
synapsing in the dorsal hornsynapsing in the dorsal horn
$ntersegmental fibers, establishing connections with
neurons in the opposite half of the spinal cord, cross
the midline in the anterior white commissure
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Ascending Spinal Tracts
Transmit impulses: oncerned with specific sensory modalities:
pain, temperature, touch, proprioception, thatreach a conscious level (cerebral corte") #orsal column funiculi 'pinothalmic tracts
7rom tactile and stretch receptors to
subconscious centers(cerebellum) 'pinocerebellar tracts
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Three ma6or pathways carry sensory informationThree ma6or pathways carry sensory information
-osterior column pathway (gracile 2 cuneate-osterior column pathway (gracile 2 cuneate
fasciculi)fasciculi) %nterolateral pathway (spinothalamic)%nterolateral pathway (spinothalamic)
'pinocerebellar pathway'pinocerebellar pathway
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Ascending Spinal Tracts
#orsal white column#orsal white column 9ateral spinothalamic9ateral spinothalamic
%nterior spinothalamic%nterior spinothalamic
%nterior spinocerebellar%nterior spinocerebellar
-osterior spinocerebellar-osterior spinocerebellar uneocerebellaruneocerebellar
'pinotectal'pinotectal
'pinoreticulr'pinoreticulr
'pinoolivary'pinoolivary
isceral sensory tractsisceral sensory tracts
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Dorsal Col"mnDorsal Col"mn Contains two tracts,Contains two tracts, FasciculusFasciculus
gracilis (FG)gracilis (FG)&& asciculusasciculuscuneatus (FC)cuneatus (FC)
Carry impulses concerned withCarry impulses concerned with
proprioception andproprioception and
discriminati!e touch romdiscriminati!e touch rom
ipsilateralipsilateralside o "odyside o "ody
Contain the a#ons oContain the a#ons o primaryprimary
a$erent neuronsa$erent neuronsthat ha!ethat ha!e
entered cord through dorsalentered cord through dorsal
roots o spinal ner!esroots o spinal ner!es
FGcontains %"ers recei!ed at sacral, lum"ar andlower thoracicle!els, FCcontains %"ers recei!ed atupper thoracic and cer!ical le!els
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7ibers ascend without7ibers ascend withoutinterruption where they terminateinterruption where they terminateuponupon ;;ndndorder neuronsorder neuronsininnucleus gracilis and nucleusnucleus gracilis and nucleuscuneatuscuneatus
The a"ons of the ;The a"ons of the ;ndndorderorderneuronsneurons decussatedecussatein thein themedulla asmedulla as internal arcuate fibersinternal arcuate fibersand ascend through the brainand ascend through the brainstem asstem as medial lemniscusmedial lemniscus..
The medial lemniscus terminatesThe medial lemniscus terminatesin thein the ventral posterior nucleus ofventral posterior nucleus ofthe thalamusthe thalamusuponupon 33rdrdorderorderneuronsneurons, which pro6ect to the, which pro6ect to thesomatosensory corte"somatosensory corte"(thalamocortical fibers)(thalamocortical fibers)
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Spinothalamic TractsSpinothalamic Tracts 9ocated lateral and ventral to9ocated lateral and ventral to
the ventral hornthe ventral horn arry impulses concernedarry impulses concerned
withwith painpain andand thermalthermalsensationssensations (lateral tract)(lateral tract)andandalsoalso non discriminativenon discriminativetouchtouchandand pressurepressure (medial(medial
tract)tract) 7ibers of the two tracts are7ibers of the two tracts are
intermingled to some e"tentintermingled to some e"tent $n brain stem, constitute the$n brain stem, constitute the
spinal lemniscusspinal lemniscus 7ibers are highly somato7ibers are highly somato
topically arranged, with thosetopically arranged, with thosefor thefor the lower limblower limblying mostlying mostsuperficiallysuperficially and those for theand those for theupper limbupper limblyinglying deeplydeeply
Information is sent to the
primary sensory cortex on
the opposite side of the body
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#ateral Spinothalamic Tract#ateral Spinothalamic Tract arries impulses concernedarries impulses concerned
withwith painpainandand thermalthermalsensations.sensations.
%"ons of +%"ons of +stst order neuronsorder neuronsterminate in the dorsal hornterminate in the dorsal horn
%"ons of ;%"ons of ;ndndorder neuronorder neuron(mostly in the(mostly in the nucleusnucleuspropriusproprius),), decussate withindecussate withinone segmentone segmentof their origin, byof their origin, bypassing through the ventralpassing through the ventral
white commissure 2 terminatewhite commissure 2 terminateon 3on 3rdrdorder neurons inorder neurons in ventralventralposterior nucleusposterior nucleusof theof thethalamusthalamus
Thalamic neurons pro6ect toThalamic neurons pro6ect to
thethe somatosensory corte"somatosensory corte"
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$nterior Spinothalamic Tract$nterior Spinothalamic Tract
arries impulses concernedarries impulses concerned
withwith non discriminative touchnon discriminative touchandand pressurepressure %"ons of +%"ons of +stst order neuronsorder neurons
enter cord terminate in theenter cord terminate in thedorsal horndorsal horn
%"ons of ;%"ons of ;ndnd
order neuronorder neuron(mostly in the(mostly in the nucleusnucleuspropriusproprius)) may ascend severalmay ascend severalsegments before crossingsegments before crossingtotoopposite side by passingopposite side by passingthrough the ventral whitethrough the ventral white
commissure 2 terminate on 3commissure 2 terminate on 3rdrdorder neurons inorder neurons in ventralventralposterior nucleusposterior nucleusof theof thethalamusthalamus
Thalamic neurons pro6ect toThalamic neurons pro6ect to
thethe somatosensory corte"somatosensory corte"
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Spino%retic"lo%thalamic SystemSpino%retic"lo%thalamic System
The system represents an additional routeThe system represents an additional routeby whichby which dull, aching paindull, aching painis transmitted tois transmitted to
a conscious levela conscious level
'ome'ome ;;ndnd
order neuronsorder neuronsterminate in theterminate in thereticular formationreticular formationof the brain stem,of the brain stem,
mainly within the medullamainly within the medulla
1eticulothalamic fibers1eticulothalamic fibersascend toascend tointralaminar nuclei of thalamusintralaminar nuclei of thalamus, which in, which in
turn activate the cerebral corte"turn activate the cerebral corte"
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Spinocereellar TractsSpinocereellar Tracts
The spinocerebellar systemThe spinocerebellar system
consists of a se/uence ofconsists of a se/uence ofonlyonly two neuronstwo neurons Two tracts:Two tracts: -osterior-osterior22
%nterior%nterior 9ocated near the9ocated near the
dorsolateral and ventrolateraldorsolateral and ventrolateralsurfaces of the cordsurfaces of the cord ontain a"ons of theontain a"ons of the secondsecond
order neuronsorder neurons arry information derivedarry information derived
from muscle spindles, Golgifrom muscle spindles, Golgitendon organs and tectiletendon organs and tectilereceptors to the cerebellumreceptors to the cerebellumfor the control of posture andfor the control of posture andcoordination of movementscoordination of movements
P t i S i llPosterior Spinocereellar
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Posterior SpinocereellarPosterior Spinocereellar
TractsTracts -resent only above level-resent only above level
9393 The cell bodies of ;The cell bodies of ;ndnd
order neuron lie inorder neuron lie in larslars
columncolumn
%"ons of ;%"ons of ;ndndorder neuronorder neuron
terminateterminate ipsilaterallyipsilaterally
(uncrossed) in the(uncrossed) in the
cerebellar corte"cerebellar corte"bybyentering through theentering through the
inferior cerebellarinferior cerebellar
pedunclepeduncle
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'entral Spinocereellar Tracts'entral Spinocereellar Tracts The cell bodies of ;The cell bodies of ;ndndorder neuronorder neuron
lie inlie in base of the dorsal hornbase of the dorsal hornof theof thelumbosacral segmentslumbosacral segments
%"ons of ;%"ons of ;ndndorder neuronorder neuron crosscrosstoto
opposite side, ascend as far asopposite side, ascend as far as
the midbrain, and then mae athe midbrain, and then mae asharp turn caudally and enter thesharp turn caudally and enter the
superior cerebellar pedunclesuperior cerebellar peduncle
The fibers cross the midline for aThe fibers cross the midline for a
second time within the cerebellumsecond time within the cerebellum
before terminating in thebefore terminating in the
cerebellar corte"cerebellar corte"
8oth spinocerebellar tracts convey8oth spinocerebellar tracts convey
sensory information to the samesensory information to the same
side of the cerebellumside of the cerebellum
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Spinotectal TractSpinotectal Tract
%scends in the anterolateral%scends in the anterolateralpart in close association withpart in close association withspinothalamic systemspinothalamic system
-rimary afferents reach dorsal-rimary afferents reach dorsalhorn through dorsal roots andhorn through dorsal roots and
terminate onterminate on ;;ndnd
order neuronsorder neurons TheThe cell bodies of ;cell bodies of ;ndndorderorder
neuron lie inneuron lie in base of the dorsalbase of the dorsalhornhorn
%"ons of ;%"ons of ;ndndorder neuronorder neuroncross to opposite sidecross to opposite side, and, andpro6ect to thepro6ect to the peria/uiductalperia/uiductalgray matter and superiorgray matter and superiorcolliculuscolliculusin the midbrainin the midbrain
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Spino % oli(ary TractSpino % oli(ary Tract
$ndirect spinocerebellar pathway (spino
olivocerebellar)
$mpulses from the spinal cord arerelayed to the cerebellum via inferior
olivary nucleus
onveys sensory information to thecerebellum
7ibers arise at all level of the spinal cord
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Spinoretic"lar TractSpinoretic"lar Tract
*riginates in laminae $*riginates in laminae $
$$$$$$
ontainsontains uncrosseduncrossed
fibers that end infibers that end in
medullary reticularmedullary reticularformationformation 22crossed 2crossed 2
uncrossed fibers thatuncrossed fibers that
terminate in pontineterminate in pontine
reticular formationreticular formation 7orm part of the7orm part of the
ascending reticularascending reticular
activating systemactivating system
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Somatic Motor PathwaysSomatic Motor Pathways
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Motor PathwaysMotor Pathways ' issues motor commands in response to' issues motor commands in response to
information provided by sensory systems, sent byinformation provided by sensory systems, sent bythe somatic nervous system ('') and thethe somatic nervous system ('') and theautonomic nervous system (%')autonomic nervous system (%')
onscious and subconscious motor commandsonscious and subconscious motor commands
control seletal muscles by traveling over 3control seletal muscles by traveling over 3integrated motor pathwaysintegrated motor pathways TheThe corticospinalcorticospinalpathwaypathway< voluntary control of< voluntary control of
motor activitymotor activity
orticobulbar tractsorticobulbar tracts orticospinal tractsorticospinal tracts TheThemedialmedial andand laterallateralpathwayspathways< modify or direct< modify or direct
seletal muscle contractions by stimulating,seletal muscle contractions by stimulating,
facilitating, or inhibiting lower motor neuronsfacilitating, or inhibiting lower motor neurons
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Motor PathwaysMotor Pathways5 ontain a se/uence ofontain a se/uence of T=*T=*
neuronsneuronsfrom the cerebralfrom the cerebralcorte" or brain stem to thecorte" or brain stem to the
musclesmuscles5 >pper motor neuron>pper motor neuron: has cell: has cell
body in the cerebral corte" orbody in the cerebral corte" or
brain stem, a"onbrain stem, a"on decussatesdecussatesbefore terminating on the lowerbefore terminating on the lower
motor neuronmotor neuron5 9ower motor neuron9ower motor neuron: has cell: has cell
body in the ventral horn of thebody in the ventral horn of thespinal cord, a"on runs in thespinal cord, a"on runs in the
ipsilateralipsilateralventral root of theventral root of the
spinal nerve and supply thespinal nerve and supply the
muscle.muscle.
UMN
LMN
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escending Spinal Tracts
*riginate*riginatefrom thefrom the cerebral corte"cerebral corte"22 brainbrainstemstem
oncernedoncernedwith:with:
ontrol of movementsontrol of movements &uscle tone&uscle tone
'pinal refle"es 2 e/uilibrium'pinal refle"es 2 e/uilibrium
&odulation of sensory transmission to&odulation of sensory transmission tohigher centershigher centers
'pinal autonomic functions'pinal autonomic functions
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The motor pathways areThe motor pathways are
divided into two groupsdivided into two groups #irect pathways#irect pathways
(voluntary motion(voluntary motion
pathways) pathways) thethe
pyramidal tractspyramidal tracts $ndirect pathways$ndirect pathways
(postural pathways)(postural pathways),,
essentially all others essentially all others the e"trapyramidalthe e"trapyramidal
pathwayspathways
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Direct )Pyramidal* SystemDirect )Pyramidal* System
1egulates fast and fine (silled) movements1egulates fast and fine (silled) movements *riginate in the pyramidal neurons in the*riginate in the pyramidal neurons in theprecentral gyri,precentral gyri,
$mpulses are sent through the$mpulses are sent through the corticospinalcorticospinal
tractstracts and synapse in the anterior hornand synapse in the anterior horn 'timulation of anterior horn neurons activates'timulation of anterior horn neurons activates
seletal musclesseletal muscles -art of the direct pathway, called-art of the direct pathway, called corticobulbarcorticobulbar
tractstracts, innervates cranial nerve nuclei, innervates cranial nerve nuclei
ndirect )+,trapyramidal*ndirect )+,trapyramidal*
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ndirect )+,trapyramidal*ndirect )+,trapyramidal*
SystemSystem
omple" and multisynaptic pathwaysomple" and multisynaptic pathways The system includes:The system includes:
5 1ubrospinal tracts1ubrospinal tracts: control fle"or muscles: control fle"or muscles
5
estibulospinal tractsestibulospinal tracts: maintain balance and: maintain balance andpostureposture
5 Tectospinal tractsTectospinal tracts: mediate head nec, and eye: mediate head nec, and eye
movementmovement
5 1eticulospinal tracts1eticulospinal tracts
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Descendin! Spinal TractsDescendin! Spinal Tracts
-yramidal-yramidal orticospinalorticospinal
!"trapyramidal!"trapyramidal 1ubrospinal1ubrospinal
TectospinalTectospinal estibulospinalestibulospinal
*livospinal*livospinal
1eticulospinal1eticulospinal
#escending#escending
%utonomic 7ibers%utonomic 7ibers
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Corticospinal Tracts
oncernedoncernedwithwith
voluntary, discrete, silledvoluntary, discrete, silled
movements, especiallymovements, especially
those of distal parts of thethose of distal parts of the
limbs (fractionatedlimbs (fractionated
movements)movements) $nnervate$nnervate thethe
contralateral side of thecontralateral side of the
spinal cordspinal cord
-rovide-roviderapid directrapid directmethod for controllingmethod for controlling
seletal muscleseletal muscle
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*rigin*rigin: motor and sensory: motor and sensory
corticescortices
%"ons pass through%"ons pass through coronacorona
radiataradiata,, internal capsuleinternal capsule,, cruscrus
cerebricerebri andand pyramidpyramidofof
medulla oblongatamedulla oblongata $n the caudal medulla about$n the caudal medulla about
?@AB?@ABof the fibersof the fibersdecussatedecussateand form theand form thelateral corticospinal tractlateral corticospinal tract
1est of the fibers remain1est of the fibers remain
ipsilateralipsilateraland formand form anterioranteriorcorticospinal tractcorticospinal tract. They. Theyalso decussate beforealso decussate beforeterminationtermination
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#istribution#istribution:: @@ terminate at@@ terminate at
cervicalcervicalregionregion ;B at;B at thoracicthoracic ;@ at;@ at lumbosacrallumbosacral
levellevel
TerminationTermination:: entral hornentral hornneuronsneurons(mostly through(mostly throughinterneurons, a few fibersinterneurons, a few fibersterminate directly)terminate directly)
Corticobulbar tractsendend
at the motor nuclei of sat the motor nuclei of sof the contralateral sideof the contralateral side
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-"rospinal Tract-"rospinal Tract ontrolsontrols the tone of limbthe tone of limb
fle"or muscles, beingfle"or muscles, beinge"citatory to motor neuronse"citatory to motor neurons
of these musclesof these muscles
*rigin*rigin: 1ed nucleus: 1ed nucleus
%"ons course ventro%"ons course ventromedially, cross inmedially, cross in ventralventral
tegmental decussationtegmental decussation,,
descend in spinal corddescend in spinal cord
ventral to the lateralventral to the lateralcorticospinal tractcorticospinal tract
orticorubrospinal pathwayorticorubrospinal pathway
(!"trapyramidal)(!"trapyramidal)
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Tectospinal Tract &ediates refle" movements of&ediates refle" movements of
the head and nec in responsethe head and nec in responseto visual stimulito visual stimuli
*rigin*rigin: 'uperior colliculus: 'uperior colliculus
%"ons course ventromedially%"ons course ventromedially
around the peria/ueductal grayaround the peria/ueductal graymatter, cross inmatter, cross in dorsaldorsal
tegmental decussationtegmental decussation,,
descend in spinal cord near thedescend in spinal cord near the
ventral median fissure,ventral median fissure,
terminate mainly interminate mainly in cervicalcervical
segmentssegments
orticotectospinal pathwayorticotectospinal pathway
(!"trapyramidal)(!"trapyramidal)
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'esti"ulospinal Tracts 9ateral estibulospinal9ateral estibulospinal
TractsTracts *rigin*rigin:: lateral vestibularlateral vestibular
(#eiters) nucleus(#eiters) nucleus
%"ons descend%"ons descend ipsilaterallyipsilaterallyinin
the ventral funiculusthe ventral funiculus Terminate on ventral hornTerminate on ventral horn
cells throughout the length ofcells throughout the length of
spinal cordspinal cord
0as e"citatory influences0as e"citatory influencesupon e"tensor motor neurons,upon e"tensor motor neurons,
control e"tensor muscle tonecontrol e"tensor muscle tone
in the antigravity maintenancein the antigravity maintenance
of postureof posture
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'esti"ulospinal Tracts
&edial vestibulospinal&edial vestibulospinal
tracttract *rigin*rigin::medial vestibularmedial vestibular
nucleusnucleus
%"ons descend%"ons descend bilaterallybilaterallyinin
the ventral funiculus, with thethe ventral funiculus, with the
medial longitudinal fasciculusmedial longitudinal fasciculus
&ost of the fibers end in the&ost of the fibers end in the
cervical region, some reachingcervical region, some reaching
upper thoracic segmentsupper thoracic segments $nvolved in movements of the$nvolved in movements of the
head re/uired for maintaininghead re/uired for maintaining
e/uilibriume/uilibrium
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eticulospinal Tracts
$nfluence$nfluencevoluntary movement,voluntary movement,
refle" activity and muscle tone byrefle" activity and muscle tone bycontrolling the activity of bothcontrolling the activity of bothalpha and gamma motor neuronsalpha and gamma motor neurons
&ediate pressor and depressor&ediate pressor and depressoreffect on the circulatory systemeffect on the circulatory system
%re involved in control of breathing%re involved in control of breathing *rigin*rigin: pontine 2 medullary: pontine 2 medullary
reticular formationreticular formation &edial (pontine) reticulospinal&edial (pontine) reticulospinal
tract descendstract descends ipsilaterallyipsilaterally 9ateral (medullary) reticulospinal9ateral (medullary) reticulospinal
tract descendstract descends bilaterallybilaterally 8oth tracts located in the ventral8oth tracts located in the ventral
funiculusfuniculus
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escending Autonomic Fi"ers
The higher centersThe higher centers
associated with the control ofassociated with the control of
autonomic activity areautonomic activity are
situated mainly in thesituated mainly in the
hypothalmaushypothalmaus
The fibers run in theThe fibers run in thereticulospinal tractsreticulospinal tracts
Terminate on theTerminate on the autonomicautonomic
neuronsneuronsin the lateral horn ofin the lateral horn of
thoracic 2 upper lumbarthoracic 2 upper lumbar(sympathetic) and sacral(sympathetic) and sacral
segments (parasympathetic)segments (parasympathetic)
levels of the spinal cordlevels of the spinal cord
##
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#o(e#o(e
nat"renat"re