nervous systems: part iv the organizaon and funcon of...

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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