nervous systems: part iv the organizaon and funcon of...
TRANSCRIPT
NervousSystems:PartIVTheorganiza8onandfunc8onofmajor
partsofthenervoussystem.
KP1:ThePeripheralNervousSystemhandlesinputs/outputswhiletheCentralNervousSystemmakesdecisions/processes
• CNSOrgans:– Brain– SpinalCord
• PNSDivisions:– Cranialnerves– Spinalnerves– Ganglia
KP2:Thebrainiscomposedof“white”and“gray”maHer.
• White:Myelinatedneurons(helpsusthink/process)• Gray:Unmyelinatedneurons(coordinatessignals)
• Thecentralcanalofthespinalcordandtheventriclesofthebrainarehollowandfilledwithcerebrospinalfluid(CSF).
• CSFisacolorlessfluidproducedinthechoroidplexusoftheventriclesofthebrain.
• CSFoccupiesthesubacrachnoidspaceofthemeningessurroundingthebrainandspinalcord.– Cushionsthebrainandspinalcord– Providesnutrientsandremovewastes
KP3:ThespinalcordsendssignalsoriginaSngfromthebraintothebodyandhandlesreflexes
KP4:Gliaarecellsthatsupport,nourish,andregulateneurons
• Manytypesexist:– Embryonicradialglia:formtracksalongwhichnewlyformedneuronsmigrate
– Astrocytes:inducecellsliningcapillariesintheCNStoformSghtjuncSons,resulSnginablood-brainbarrierandrestricSngtheentryofmostsubstancesintothebrain
KP5:Vertebrateshaveregionallyspecializedbrains
• SpecializaSonneededtoperformdiversefuncSons
• Thesestructuresariseduringembryonicdevelopment
TheCerebrumorCortex:
• Thecerebrumorcortexisthelargestpartofthehumanbrain
• associatedwithhigherbrainfuncSonsuchasthoughtandacSon,percepSon,voluntarymovement,andcogniSvefuncSons(learningandmemory).
• ThecerebralcortexisparScularlyextensiveinmammals
• Inhumansitconsistsof80%ofbrainmassandishighlyconvolutedtoincreasesurfacearea.
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Adultbrainviewedfromtherear
Cerebellum
BasalnucleiCerebrum
LeMcerebralhemisphere
Rightcerebralhemisphere
Cerebralcortex
Corpuscallosum
Diencephalon
ThalamusPinealglandHypothalamusPituitarygland
Spinalcord
Brainstem
Midbrain
Pons
Medullaoblongata
Cerebrum Diencephalon
Midbrain
Pons
Medullaoblongata
CerebellumSpinalcord
Child
CEREBELLUM
• Partofthehindbrain.• InformaSonprocessing• Balance,postureandcoordinaSon• Monitorsmotorandvisualandauditorycommandsreceivedfromthecortex.
• Helpsinlearningandrememberingmotorskills.
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CorpusCallosum
• Athickbandofaxonsthatenablestherightandleccerebralhemispherestocommunicate.
• ThelecsideofthecortexreceivesinformaSonfrom,andcontrolsthemovementof,therightsideofthebody,andviceversa.
• Eachcerebralhemisphereisspecializedfordifferenttasks-e.g.,therightforfacerecogniSonandthelecforlanguage.
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Hypothalamus
• ThestructureisinvolvedinfuncSonsincludinghomeostasis,emoSon,thirst,hunger,circadianrhythms,andcontroloftheautonomicnervoussystem.
• InaddiSon,itcontrolsthepituitaryandcoordinateswiththeadrenalglandsviathehypothalamus/pituitary/adrenalaxis.
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Hippocampus:memorycenter
• Thispartofthemid-brainisimportantforlearningandmemory
• ConverSngshorttermmemorytomorepermanentmemory
• ForrecallingspaSalrelaSonshipsintheworldaboutus
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TheLimbicSystem(EmoSonalBrain)
• Thelimbicsystemincludesagroupofstructuressurroundingthebrainstem(fromtheLaSnLimbus,border).
• Amygdala,hippocampus,partsofthethalamus,hypothalamus
• EmoSons,moSvaSon,olfactory,behaviorandmemory.
• ThefocusofemoSonalmemoryistheamygdala.
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LanguageandSpeech
• StudiesofbrainacSvityhavemappedareasresponsibleforlanguageandspeech
• Broca’sareainthefrontallobeisacSvewhenspeechisgenerated
• Wernicke’sareainthetemporallobeisacSvewhenspeechisheard
• Theseareasbelongtoalargernetworkofregionsinvolvedinlanguage.
InformaSonProcessing
• Thecerebralcortexreceivesinputfromsensoryorgansandsomatosensoryreceptors
• SomatosensoryreceptorsprovideinformaSonabouttouch,pain,pressure,temperature,andtheposiSonofmusclesandlimbs
• ThethalamusdirectsdifferenttypesofinputtodisSnctlocaSons
FrontalLobeFuncSon
• FrontallobedamagemayimpairdecisionmakingandemoSonalresponsesbutleaveintellectandmemoryintact
• ThefrontallobeshaveasubstanSaleffecton“execuSvefuncSons”ofthinkingandmakingdecisions.
EfferentneuronsAfferentneurons
CentralNervousSystem
(informa8onprocessing)
PeripheralNervousSystem
Sensoryreceptors
Internalandexternal
s8muli
Autonomicnervoussystem
Motorsystem
Controlofskeletalmuscle
Sympathe8cdivision
Parasympathe8cdivision
Entericdivision
Controlofsmoothmuscles,cardiacmuscles,glands
PeripheralNervousSystemFuncSons
• MotorSystem:NeuronsthatcarrysignalstoskeletalmusclesmainlyasaresponsetoexternalsSmuli.
• AutonomicNervousSystem:involuntarycontroloverorgans
• Parasympathe8cNervousSystem:RestanddigesSon
• Sympathe8cnervousSystem:Fightorflight
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ReviewofIndependentPracSce:
• Thecerebrumorcortex:• Cerebellum:• CorpusCallosum:• Hypothalamus:• Hippocampus:• TheLimbicSystem:
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ExitTicket:Think-pair-share:
• Ifawomanwithaseveredcorpuscallosumviewedaphotographofafamiliarface,firstinthelecfieldofvisionandthenintherightfield,whywoulditbedifficultforhertoputanametothefaceineitherfield?
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EXITTICKETResponse:
• Eachcerebralhemisphereisspecializedfordifferentpartsofthistask-
• therightforfacerecogniSonandthelecforlanguage.
• Withoutanintactcorpuscallosum,neitherhemispherecantakeadvantageoftheother’sprocessingabiliSes.
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