APPSYCHUnit3ABiologicalBasisOfBehavior

NeuralProcessing&TheEndocrineSystem

1. Everythingpsychologicalissimultaneouslybiological

2. Whatareneuronsandhowdotheycommunicate?

3. Howdoneurotransmittersinfluencebehavior?

4. Howdodrugsandotherchemicalsaffectneurotransmission?

PsychologyandBiology• Everythingpsychologicalissimultaneously

biological.– Everythinggoingoninourmindcoincideswithsomethinggoingininourbody

– Tothink,feel,oractwithoutabodywouldbelikerunningwithoutlegs.

– Wearebio-psycho-socialsystems.• Biological,psychologicalandsocialsystemsinteracttoproduceourmind&behavior

BiologicalPsychology

• A.NervoussystemB.BrainC.Genetics• Nature&nurturetogether• Wehavecomealongwayinunderstandinghowthebrainisrelatedtobehavior:– Phrenology

• BiologicalPsychology – linksbetweenbiologyandbehavior,betweenbiologicalactivityandpsychologicalevents

Neurons

¨ Neuron = 1 cell

¨ Nerve = a bundle of neurons

3MainTasksofNeurons1. Receiveinformationfromtheneuronsthatfeedit.2. Carryinformationdownitslength.3. Passtheinformationontothenextneuron.

3TypesofNeurons• Canbedifferentsizesandshapes,allsharesimilarstructure,andfunctioninasimilarway.

• 3categoriesbasedonneuronlocationandfunction:1. SensoryNeurons2. MotorNeurons3. Interneurons

SensoryNeurons

• Sensoryneurons:one-waymessagefromthesenseorganstoward thespinalcordorbrain.

• Communicateallofyoursensoryexperience; includingvision,hearing,taste,touch,smell,painandbalance.

MotorNeurons

• Motorneuronsone-waymessagesaway fromthespinalcordorbraintothemuscles,organsandglands.

Interneurons

• Sensory&motorneuronsdonotcommunicatedirectlywitheachother.Instead,theyrelyonamiddle-man.

• Interneurons (themajorityofourneurons)relaymessagesfromsensoryneuronstootherinterneuronsormotorneuronsincomplexpathways.

PartsofaNeuron• Dendrites– receivemessages• CellBody(soma)– directactivity• Axon– passageway• MyelinSheath– pushesmessages/

protects

• AxonTerminal– sendsinfo• Synapse– spacebetweenneurons

Dendrites• Thedendrite,or“receiver” partoftheneuron,acceptsmostoftheincomingmessages.– Consistsoffinelybranchedfibers.– Selectivelypermeable

Axon

• Axon:neuralimpulsesaresentthroughtheends

• Insomeneurons(brain)axonsareveryshort.

• Inothers,likethoseintheleg,theycanreach3feetlong.– (Imagineabasketballattachedtoarope7kmlong!)

MyelinSheath

• Themyelinsheathprotectstheaxonandtheelectricsignalthatitiscarrying

• Liketheplasticcoatingdoesonelectriccord.– Ifmyelinsheathdeteriorates- MS

ActionPotential• Informationtravelsalongtheaxonintheformofanelectricalchargecalledtheactionpotential.

• Theactionpotentialisthe“fire” signaloftheneuronandcausesneurotransmitterstobereleasedbytheterminalbuttons.

ActionPotential

RefractoryPeriod• Betweeneachactionpotentialisbriefrechargingtime:refractoryperiod.• Afterrefectoryperiodneuroniscapableofanotheractionpotential.– Analogy:waitingfortheflashtorechargeonadisposablecamerabeforeyoucantakeanotherpicture.

– Analogy:waitingfortoilettofillwithwaterbetweenflushes

Threshold• Neuronreceivesinfofromthousandsofotherneurons– Someexcitatory(likepushingthegaspedal)– Othersareinhibitory(likepushingthebreaks)

• Iftheexcitatorysignals,minustheinhibitorysignalsexceedaminimumintensity,calledthe threshold,thenactionpotentialisrealized.– Analogy:Topullthetriggerofagun,ittakesacertainthresholdoffingerpressuretofullysqueezeitandforcethetriggertoshoot

AllorNoneResponse• Oncetheactionpotentialisreleased,thereisnogoingback.• Theaxoneither“fires” oritdoesnot:all-or-noneresponse.– Howdowedetectagentletouchfromaslap?– Astrongstimulus,likeaslap,cantriggermoreneuronstofire,moreoften,butnotanystronger.• Analogy:Squeezingatriggerharderwontmakethebulletgofaster.

AFieldTrip!!!!

• Nowthatweneuronsfirewewillgolookattheneuronmodelsourschoolhas.

• Todothis,wewillhavetotakeafieldtrip….TOTHEBATHROOM

• Itjustsohappens,thattoiletsaretheperfectexamplesofneurons.

HowneuronscommunicateNeuronsuseanelectro-chemicalprocess tosendmessages

• Whyelectrical?– Pushinginformationthroughaxonisbasedonprocessofpositiveandnegativechargesofelectricalatoms(ions)• Potassium(K+),Sodium(Na+),Chloride(Cl-)

• Whychemical?– Neurotransmitterscrosssynapse:differentonessenddifferentimpulsesandneedtofindreceptors

– Itcaneitherexcite(fire)orinhibit(preventfiring)

• Messagesaresentataspeedof2-200mph

Depolarization

• Depolarizationistheinitialmovementoftheactionpotentialwheretheactionpassesfromtherestingpotentialinthecellbodyintotheactionpotentialintheaxon.

HowCellsConnect

• Neuronsdonotactuallytoucheachothertopassoninformation.Thegapbetweenneuronsiscalledthesynapse.

• Thesynapseactsasanelectricalinsulator,preventinganelectricalchargefromracingtothenextcell.

• Neurotransmitters chemicalsusedinneuralcommunication.• Iftheyhavetherightfit,thetransmittersfitintothereceptorslikeakeyintoalock.

NeuralCommunication

• Thechemicalsthatourbodiesproduceworkasagonists(excite)andantagonists(inhibit).Theydothisbyamplifying ormimicking thesensationofpleasure(agonist),orblocking theabsorptionofourneurotransmitters(antagonist).

• Agonist-opiatesmimicthehighproducednaturally• Antagonist-botulinblocksACh (enablesmuscleaction)

CommonNeurotransmitters/Functions

AHumanChainofNeurons

• Nowwewilldoademonstrationthatwillshowhowneuronsworkandtravel.

• Eachpersonneedstostandupandforma“congaline”

APPSYCHUnit3ATheNervous&EndocrineSystems

1. Whatarethefunctionsofthenervoussystem’smaindivisions?

2. Canyourememberfeelinganextendedperiodofdiscomfortaftersomeparticularlystressfulevent?Howlongdidthosefeelingslast?

TheNervousSystem

• CentralNervousSystem(CNS)– Includesallneuronsinbrainandspinalcord

• PeripheralNervousSystem(PNS)– Neurons(sensoryandmotor)thatruntoandfromCNS• Connectsfingers,toes,etc.tospinalcord

TheCentralNervousSystemCNS• TheCentralNervousSystemincludesthebrainandthespinalcord.

• Theyaresoimportanttothehumanbodythattheyareencasedinboneforprotection-

• Supportforevolutionarypsychologists

ThePeripheralNervousSystemPNS

• ThePeripheralNervousSystemcontainsallofthenerveswhichfeedintothebrainandspinalcord.

ThePeripheralNervousSystem

SomaticNervousSystem(SNS)• Controlsbody’sskeletal

muscles• Sendsmessagesbackand

forthtobrainaboutsenseandmovement– Example:feelahotstoveandpullhandaway

ThePeripheralNervousSystem

AutonomicNervousSystem(ANS)• Regulatesactivitiesofvitalorgans– Lungs,stomach,intestines,heartliver,eliminativeorgans,andreproductiveorgans

– Weusuallycannotvoluntarilycontroltheseactivities• Exceptions:holdbreath,controlbloodpressure,blinking,sneezing

Nowlet’sthinkofsomememorizationtechniquesforthesesystems

ThePeripheralNervousSystem2divisionsoftheANS:

• SympatheticNervousSystem– Arouses usfordefensiveaction–mobilizesenergy

(↑heartbeat,↓digestion,↑bloodsugar)“fightorflight” response

• ParasympatheticNervousSystem– Calms usdown– conservesenergy(↓heartbeat,↓bloodsugar,etc.)

Reflexes• Ourautomaticresponsetostimuliare reflexes.– Asimplespinalreflexpathwayiscomposedofasinglesensoryneuronandasinglemotorneuron,connectedthroughthespinewithaninterneuron.

– Thistypeofresponsedoesnotinvolvethebrain,andisoftenwhywefeelourbodymovebeforewefeelthestimuli• Aheadlessbodycoulddemonstrateareflexlikethatproducedwhenhittingthepatellartendonwithahammer.

TheEndocrineSystem

• Theendocrinesystemisthebody’schemicalmessengersystem,thatreliesonhormones.– Itinvolvestheendocrineglands:pituitary,thyroid,parathyroid,adrenals,pancreas,ovaries,andtestes.

• Hormonesarechemicalmessengersusedbytheendocrinesystem.Manyhormonesarealsoneurotransmitters.

WorkingwithOtherSystems• Undernormal (unaroused)conditions,theendocrinesystemworksinparallel

withtheparasympatheticnervoussystemtosustainourbasicbodyprocesses.• Incrisis,theendocrinesystemshiftsintoanewmodetosupportthe

sympatheticnervoussystem….itreleasesepinephrine(adrenalin)– Triggersthe“fightorflight” response

TheMasterGland

• Whilethebodyhasmanyglandswhichareimportant,themostimportantglandisthepituitarygland.– Controlsalloftheresponsesoftheendocrinesystem

• Thepituitaryglandisnolargerthanapea,andislocatedatthebaseofthebrain.

TheEndocrineSystem• Thebody’s“slow”

chemicalcommunicationsystem

• Asetofglandsthatsecretehormonesintothebloodstream