生理学英文课件(体温和调节)-Chapter-7-Metabolism-and-Temperature

EnergyMetabolism＆BodyTemperatureSECTIONAEnergyMetabolismScience.2009Jul10;325(5937):201-4.Caloricrestrictiondelaysdiseaseonsetandmortalityinrhesusmonkeys.ColmanRJ,AndersonRM,JohnsonSC,KastmanEK,KosmatkaKJ,BeasleyTM,AllisonDB,CruzenC,SimmonsHA,KemnitzJW,WeindruchR.WisconsinNationalPrimateResearchCenter,UniversityofWisconsin,Madison,WI53715,USA.rcolman@Caloricrestriction(CR),withoutmalnutrition,delaysagingandextendslifespanindiversespecies;however,itseffectonresistancetoillnessandmortalityinprimateshasnotbeenclearlyestablished.Wereportfindingsofa20-yearlongitudinaladult-onsetCRstudyinrhesusmonkeysaimedatfillingthiscriticalgapinagingresearch.InapopulationofrhesusmacaquesmaintainedattheWisconsinNationalPrimateResearchCenter,moderateCRloweredtheincidenceofaging-relateddeaths.Atthetimepointreported,50%ofcontrolfedanimalssurvivedascomparedwith80%oftheCRanimals.Furthermore,CRdelayedtheonsetofage-associatedpathologies.Specifically,CRreducedtheincidenceofdiabetes,cancer,cardiovasculardisease,andbrainatrophy.ThesedatademonstratethatCRslowsaginginaprimatespecies.美国一项研究表明，限制热量摄入，提供适量营养，可以推迟衰老，延长寿命。

Energymetabolism

Thermalequivalentoffood、

Thermalequivalentofoxygen、RespiratoryQuotient(RQ),

Non-proteinRQ(NPRQ)

Factorsaffectingenergymetabolism

Basalconditions,

BasalMetabolicRate,(BMR)

MeasurementofthemetabolicrateKeywordsGeneralconsideration1.Areviewofprincipalchemicalprocessesofthecell;2.Ananalysisoftheirphysiologicimplications,especiallythemannerinwhichtheyfitintotheoverallconceptofhomeostasis.Conceptofenergymetabolism：

Theprocessesofliberation,transformation,storageandutilizationoftheenergyproducedbythematerialmetabolisminthebody.Source,transferandstorageofenergy1)Adenosinetriphosphate(ATP)functionsasan“energycurrency”inmetabolism.2)CP(phosphocreatine)functionsasanaccessorystoragedepotforenergyandasan“ATPbuffer”Phosphocreatine+ADP=ATP+CreatineConceptof“freeenergy”TheenergyinfoodscanbemadebythechemicalreactionsinthecellsTheenergyisavailabletothevariousphysiologicsystemsofthecells.Theamountofenergyliberatedbycompletedoxidationofafoodiscalledthefreeenergyofoxidationofthefood.RepresentedbythesymbolΔG.ATPisanessentiallinkbetweenenergy-utilizingandenergy-producingfunctionsofthebody.---theenergycurrencyofthebody.Energyderivedfromtheoxidationoffoodisusedtoconvertadenosinediphosphate(ADP)toATP.ATPisthenconsumedbythevariousreactionsofthebody.Roleof“AdenosineTriphosphate(ATP)”inmetabolismMetabolicrateThemetabolismofthebodysimplymeansallthechemicalreactionsinallthecellsofthebody.Metabolicrateisnormallyexpressedintermsoftherateofheatliberationduringchemicalreactions.Heatistheendproductofalmostalltheenergyreleasedinthebody.Measurementofthewhole-bodymetabolicrate

DirectCalorimetry——

tomeasurethesumofheatproductionofwholebodyinaunitoftimephysicallydifficulttoperformusedonlyforresearchpurposesIndirectCalorimetry——

◎theprincipleofchemicalreactions◎tocheckuphowmuchcarbohydrates,fatsandproteinsareoxidizedrespectivelyincertaintimes◎tocalculatethesumofheatproductionofbodyinthistimesC6H12O6＋6O2→6CO2＋6H2O＋△H(Glucose)Measurementofthewhole-bodymetabolicrate

ThermalEquivalentofFood——

Caloriesliberatedby1gramoffoodoxidizedinbody（orburnedoutofbody）.biologicalthermalequivalent（oxidizedinbody）physicalthermalequivalent（burnedoutofbody）ThermalEquivalentofOxygen——

Intheprocessofoxidizingfood,Caloriesliberatedperliteroxygen(O2)

consumed.RespiratoryQuotient（RQ）——

Intheprocessofoxidizingfood,theratioofcarbondioxideproducedtooxygenused

CO2produced(ml)RQ＝

O2used(ml)Non-ProteinRespiratoryQuotient（NPRQ）—

Intheprocessofoxidizingthecarbohydratemixedwithfatindifferentproportion,theratioofcarbondioxideproducedtooxygenused★

mentalactivity

muscletonusandreleasinghormonesmetabolicrate

Factorsaffectingenergymetabolism

★movementofmuscles

enhances

rateofmetabolism

★

temperatureofenvironment

Metabolicrateisthemoststableduring20～30℃，riseorfallintemperatureenhancesthemetabolicrate★

ingestionoffood

(specificdynamiceffectoffoods)BasalMetabolicRate(BMR)－－

theenergymetabolismunder“basalconditions”basalconditions：

★morning,waking,lyingdownquietly,nomovement；

★hadagoodsleepthepreviousnight；★atcompleterest,noise,discomfort，andemotionalimpactsaretobeavoided；

★12hoffooddeprivationatleast；

★environmentaltemperature20～25℃。BasalMetabolicRate(BMR)－－

Themetabolismsomeasuredincludesthefundamentalbasalmetabolismofallcellsandsomesteadyfunctionssuchasthoseofthekidney,heart,andrespiratorymuscles.BMRisexpressedasCaloriesperhourpersquaremeterofbodysurfacearea,calculatedfromheightandweight.Calories/m2/hourCalculationofbasalmetabolicrateSimplifiedmethod:e.g.－－RQis0.82,ThermalEquivalentofOxygenis20.18KJ／L(fromthetable

),O2usedis15L／h(a20yearoldman,underbasalconditions)，surfaceareaofbodyis1.5m2,(calculateaccordingtoheightandweight),SotheBMRis：

20.18KJ／L×15L／h÷1.5m2＝201.8KJ／(m2·h)ThenormalvalueofBMRofthe20yearoldmanis

157.8KJ／(m2·h)(fromthetable)，Sotheman’valueisoverthenormalvalue:（201.8－157.8）÷157.8×100%≈＋28%SignificancesofChangeofBMR±10～15%

——normalover±20%——abnormalBMR

hyperthyroidism,fever,diabetes,spherocytosis,leukemia,andheartdiseaseswithdyspnea.BMR

hypothyroidism,pathologicalhunger,Addison’sdisease,nephroticsyndrome,andpituitarigenicobesity,etcSectionBBodyTemperatureRegulationBodyTemperature

—averageinternaltemperatureinbody–the“core”ofthebody.

coretemperature

shelltemperatureNormalbody/coretemperatureRectaltemperature：36.9~37.9℃Oraltemperature：36.7~37.7℃，lowerthanrectal0.5℃Axillarytemperature：36.0~37.4℃，lowerthanoral0.3℃NormalChangesCircadianrhythm,nomorethan1℃

Sex:female>maleabout0.3℃，menstruation

Age:infancy>middle-age>oldageOthers:movement,stress,exciting,ingestionoffood,etc.Thermogenesis(heatproduction)

sumofheatproduction=basalmetabolism＋specificdynamiceffectoffoods＋movementofskeletalmuscles

resttime：heatproducedmainlybythedeeporgans(liver)

movement：heatproducedmainlybyskeletalmusclescoldclimate：heatproducedbymuscletonus,shivering,hormonessecretion(Epinephrine,

Norepinephrine,Thyroxine)Thermolysis(heatloss)

throughskin（97%）,respiration（2%）,urineandexcrement（1%）Heatlossbyskin——

Radiation：temperaturedifferencebetweenskinandenvironment,effectiveradiationarea

Conduction：temperaturedifferencebetweenskinandobject,toucharea,conductingheatdegreeofobject

Convection：windspeed,flowspeed,temperaturedifferenceandeffectiveareaEvaporation：

insensibleperspiration——Heatislostbyevaporationofwaterexudedfromskinandrespiratorytract.

sensibleperspiration（sweating）——Heatislostbyevaporationofsweatsecretedbysweatgland.When:airtemperature≥skintemperature，theevaporation

isonlyonemeansofheatloss.AttentionSweatingprocessesandThermolysis

warmandhotenvironment→stimulatesskin

thermoreceptorsandheatingbloodstream→sweatingcenter（mainlyinhypothalamus）→sympatheticcholinergicfibers→smallsweatgland→thermalsweating

★Sweatingspeedaffectedbyenvironmentaltemperature,humidity,windspeed,andmovementintensity,etc.

mentalsweating

nosignificanceinthermoregulationEffectsofSkinBloodFlowonThermolysis

hotenvironment→decreasethetonusofsympatheticnervoussystem→arteriolesrelaxandarteriovenous

anastomoses

openintheskin→increasestheskinbloodflow→skintemperaturerises→increasestheheatloss

coldenvironment→increasethetonusofsympatheticnervoussystem→arteriolescontractandarteriovenous

anastomoses

closeintheskin→reducestheskinbloodflow→skintemperaturefalls→reducestheheatlossRegulationofbodytemperatureBodytemperatureiscontrolledbybalancingheatproduction

againstheatloss.Behavioralthermoregulation:Humanbeingkeepsthebodytemperatureconstantthroughmanyconsciousactivities.Theregulatoryprocessofbodytemperatureperformedbyanintrinsicautonomicregulationmechanisminthebody.AutonomicthermoregulationAutonomicthermoregulationTheregulatoryprocessofbodytemperatureperformedbyanintrinsicautonomicregulationmechanisminthebody.Thermoreceptors

★PeripheralThermoreceptor：

locatedintheskin,mucosa,andinternalorgans，coldreceptorandwarmthreceptor，bothofthemarethefree(unmyelinated)nervousterminals.

★CentralThermoreceptor：

existinginspinalcord,medullaoblongata,reticularstructureinbrainstem,andhypothalamus;inwhich,preopticanteriorhypothalamus(PO/AH)

containsheat-sensitiveneuron

andcold-sensitiveneuron

Afferentnerves(pathways):

inperipheralafferentnerves,autonomicnervoussystemandcentralafferentfibers，bloodflowisoneofafferentpathways.ThermoregulationCenters:basiccenter－inhypothalamus，anteriorhypothalamusisheatlosscenter，posteriorhypothalamusisheatproductioncenter，PO/AHareaisintegratedcenter.Efferentnerves(pathways):

Motornervessystemtotheskeletalmuscles,Endocrinesystem:epinephrine,norepinephrine,thyrine

Sympatheticadrenergicnervefibersinnervatingvesselsinskinandmucosa,Sympatheticcholinergicnervefibersinnervatingsweatgland.

Effectororgans：

heatproduction—liver,skeletalmuscles,etc；heatloss—skinvessels，sweatgland.

“set-point”theoryofthermoregulation

temperature-sensitiveneuronsinPO/AHareaexhibits“set-point”function,theset-pointisnormallysetin37℃.

Attemperaturesabovethislevel,therateofheatlossisgreaterthanthatofheatproduction,sothatthebodytemperaturefallsandreapproachesthe37℃level.

Attemperaturesbelowthislevel,therateofheatproductionisgreaterthanthatofheatloss,sothatthebodytemperaturerisesandagainapproachesthe37℃level.BehavioralcontrolofbodytemperatureAsidefromthesubconsciousmechanismsforbodytemperaturecontrol,thebody’sanothertemperature-controlmechanism,evenmorepotent.Whenevertheinternalbodytemperaturebecomestoohigh,signalsfromthetemperature-controllingareasinthebraingivethepersonapsychicsensationofbeingoverheated.Conversely,wheneverthebodybecomestoocold,signalsfromtheskinandprobablyalsofromsomedeepbodyreceptorselicitthefeelingofcolddiscomfort.therefore,thepersonmakesappropriateenvironmentaladjustmentstore-establishcomfort,suchasmovingintoaheatedroomorwearingwell-insulatedclothinginfreezingweather.Abnormalityofbodytemperatureregulation-----

Fever

FeverBodytemperatureabovetheusualrangeofnormal.Causes:1.abnormalitiesinthebrainitselfortoxicsubstancesthataffectthetemperature-regulatingcenters2.include:bacterialdiseases,braintumors,andenvironmentalconditionsthatmayterminateinheatstroke.Theset-pointofthehypothalamicthermostatisresettoahighlevel.Themechanismsofheatproductionandheatlossarebalancedonthishigherlevel.请结合你所学的知识，分析该患者出现腹痛的生理学机制。ReviewSubjectsofbestchoice:1.RQ(respiratoryquotient)is:A.Inthegivenperiodoftime,theratioofxygenusedtocarbondioxideproducedinthebody;B.Inthegivenperiodoftime,theratioofcarbondioxideproducedtooxygenusedinthebody;C.theratioofairexhaledtoairinhaledD.theratioofcarbondioxideproducedtoused2.RQvalueisminimuminwhichone?A.SugarB.proteinC.fatD.vitaminE.mineralsalt

3.ThespecificdynamiceffectismostpowerfulinwhichfoodA.SugarB.proteinC.fatD.vitaminE.mixingfood

4.Intheviewofphysiology,bodytemperatureisA.oraltemperatureB.rectaltemperatureC.armpitaltemperatureD.averageskintemperatureofthebodyE.averagecoretemperatureofthebody

A.spinalcordB.medullaoblongataC.reticularstructureofbrainstemD.preopticanteriorhypothalamus(PO/AH)E.cerebralcortex

5.Theset-pointoftemperatureregulationcenterliesin6.Mostoftheheatlostinthebodyisby:A.respiratorytractB.digestivetractC.urinarytractD.skinE.pulmonarycirculation7.Thebasalmetabolicrate(BMR)valueisthemoststableunderthecircumstancetemperaturebetween:A.10～14℃B.15～19℃C.20～30℃D.31～35℃E.36～40℃

8.Thefollowingrelatesaboutthebasalmetabolism,whichoneiswrong?A.itismeasuredunder“basalconditions”

B.theaveragevaluesforchildarelargerthanfortheadultC.Itreflectsthelowestlevelofenergymetabolismofthebody.D.itisexpressedasarelativevalueinclinicE.thevalue10～15%higherorlowerthannormalaveragevaluebelongtonormal9.Thefollowingrelatesaboutthenormalchangeofbodytemperature,whichoneisright?A.therangeofnormalchangeisirregular.B.therangeofcircadianrhythmisover2℃C.bodytemperatureislowerinafternoonthanthatinmorningD.woman’sbodytemperaturedecreasesafterovulating.E.thebodytemperatureincreasesduringmusclesactivity.10.BMRdecreasesinwhichoneofthediseaseconditionsfollowing?A.feverB.hyperthyroidismC.diabetesD.spherocytosisE.Hypothyroidism11.BMRisthecaloriescalculatedby:A.weightB.heightC.ageD.bodysurfaceareaE.circumstancetemperature12.Whichmethodisutilizedwhenwespongeafeverpatientwithalcoholtodecreasethebodytemperature?A.radiationB.conductionC.convectionD.insensibleevaporationE.evaporation13.Amalariapatientsuddenlyfeelschillyandchills,thebodytemperatureis39℃.thischangeiscausedby:A.excitementofthermolysiscenterB.inhibitionofthermogenesiscenterC.theset-pointincreasedtoahighervalueD.vasodilationofskinE.functionalimpairmentoftemperatureregulation14.Thebodytemperatureofapneumoniahyperpyrexia(肺炎高热)patientdeclinetonormalaftertheapplicationofantibiotics.Thefollowingrelatesabouttheprocessoftemperatureregulation,whichoneiswrong?A.excitementofthermolysiscenterB.inhibitionofthermogenesiscenterC.theset-pointreturnstonormallevelD.vasodilationofskinE.thefunctionalimpairmentoftemperatureregulationunderfebrileconditionrepairedtonormal15.Atnormalroomtemperature,inarestingperson,bodyheatlossismainlybywhichmeans?A.radiationB.conductionC.convectionD.insensibleevaporationE.evaporation16.Whenthetemperatureofthesurroundingsisgreaterthanthatofskin,thebodyridheat