nervous system: autonomic nervous system anat 35... · the autonomic nervous system...
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NERVOUSSYSTEM:AUTONOMICNERVOUSSYSTEM
HumanAnatomyUnit4
InAnatomyToday
FunctionalOverviewoftheNervousSystem
TheAutonomicNervousSystem• “Involuntary”• Functiontomodulateongoingautomaticactivities• Effectors(targettissues)– smoothmuscle– cardiacmuscle– glands
• Functionalexamples:– heartrate– ventilation– digestivetractactivity
ANSisaTwoNeuronSystem
• Preganglionicfibers– exittheCNSandterminateontoautonomicganglia
• Postganglionicfibers– exittheautonomicgangliaandterminateontothetarget
MotorNeuronSystems
ComponentsandSubdivisionsoftheANS
• Sympatheticdivision– Fightorflight– Preganglionic fibers
emergefromT1-L2– Postganglionicneurons
emergefromsympatheticchainganglia
• Parasympatheticdivision– Restandrepose– Preganglionic fibers
emergefrompons,medulla,S2-S4
– Postganglionicneuronswithineffector
ComponentsandSubdivisionsoftheANS
OrganizationoftheSympatheticDivision
SympatheticDivision• Sympatheticchain– Location:eithersideofvertebralcolumn– Innervateeffectorsinbodywall,insidethoraciccavity– preganglionicfiberssynapseonpostganglionicfibersveryclosetotheCNSandfarawayfromeffectororgans
• Collateralganglia– Location:betweensympatheticchainandeffector
• Adrenalmedulla– Sympatheticpreganglionicneuronsenteradrenalmedullaandstimulatepostganglionicneurons
– Cellsrespondandreleaseadrenalin(80%epinephrine,20%norepinephrine)
AnatomicalDistributionofSympatheticPostganglionicFibers
CollateralGanglia• Celiacganglion
– Stomach,duodenum,liver,pancreas,spleen,gallbladder
• Superiormesentericganglion– Smallintestines,beginning
oflargeintestines• Inferiormesenteric
ganglion– Kidney,bladder,
reproductiveorgans,largeintestines
AdrenalMedulla
OrganizationoftheParasympatheticDivision
ParasympatheticDivision
• Involvescranialnerves:III,VII,IXandX,S2-S4• Innervatesvisceralorgans• PreganglionicfiberssynapseonpostganglionicfibersfarawayfromtheCNSandwithineffectororgans
AnatomicalDistributionofParasympatheticPostganglionicFibers
DualInnervation
LevelsofAutonomicControl