《Food Nutriology》课件-1-神奇的人体3-内分泌和神经系统_第1页
《Food Nutriology》课件-1-神奇的人体3-内分泌和神经系统_第2页
《Food Nutriology》课件-1-神奇的人体3-内分泌和神经系统_第3页
《Food Nutriology》课件-1-神奇的人体3-内分泌和神经系统_第4页
《Food Nutriology》课件-1-神奇的人体3-内分泌和神经系统_第5页
已阅读5页,还剩16页未读 继续免费阅读

下载本文档

版权说明:本文档由用户提供并上传,收益归属内容提供方,若内容存在侵权,请进行举报或认领

文档简介

TheRemarkableBody神奇的人体Thebody’scellsTheHormonalandNervousSystemsSummarizetheinteractionsbetweenthehormonalandnervoussystemsandnutrition:Inadditiontofluid,bloodcells,nutrients,oxygen,andwastes,thebloodalsocarrieschemicalmessengers,hormones,fromonesystemofcellstoanother.Hormonescommunicatechangingconditionsthatdemandresponsesfromthebody'sorgans.WhatDoHormonesHavetoDowithNutrition?Hormonesaresecretedandreleaseddirectlyintothebloodbyorgansknownasglands.

Glandsandhormonesaboundinthebody.Eachglandmonitorsaconditionandproducesoneormorehormonestoregulateit.Eachhormoneactsasamessengerthatstimulatesvariousorganstotakeappropriateactions.Forexample,whenthepancreas(agland)detectsahighconcentrationoftheblood'ssugar,glucose,itreleasesinsulin,ahormone.Insulinstimulatesmuscleandothercellstoremoveglucosefromthebloodandtostoreit.Theliveralsostoresglucose.Whenthebloodglucoselevelfalls,thepancreassecretesanotherhormone,glucagon,towhichtheliverrespondsbyreleasingintothebloodsomeoftheglucoseitstoredearlier.Thus,anormalbloodglucoselevelismaintained.Nutritionaffectsthehormonalsystem.Inpeoplewhobecomeverythin,forexample,analteredhormonalbalancecausestheirbonestolosemineralsandweaken.Overlythinwomenmayalsoceasetomenstruate,aprocessregulatedbyhormones.内分泌和激素Insulinfunctions

Thehormonalsystemalsoaffectsnutrition.Hormones:Carrymessagestoregulatethedigestivesysteminresponsetomealsorfasting.Informthebrainaboutthedegreeofbodyfatness.Helptoregulatehungerandappetite.Influenceappetitechangesduringawoman'smenstrualcycleandinpregnancy.Regulatethebody'sreactiontostress,suppressinghungeranddigestion.Inaddition,analteredhormonalstatecontributestothelossofappetitethatsickpeopleoftenexperience.Whentherearequestionsaboutaperson'snutritionorhealth,thestateofthatperson'shormonesisoftenpartoftheanswer.

Glandssecretehormonesthatactasmessengerstohelpregulatebodyprocesses.KeypointsHowDoestheNervousSystemInteractwithNutrition?Thebody’sothermajorcommunicationsystemis,ofcourse,thenervoussystem.Withthebrainandspinalcordascentralcontrollers,thenervoussystemreceivesandintegratesinformationfromsensoryreceptorsalloverthebody-sight,hearing,touch,smell,taste,andothers-whichcommunicatetothebrainthestateofboththeouterandtheinnerworlds,includingtheavailabilityoffoodandtheneedtoeat.Thenervoussystemalsosendsinstructionstothemusclesandglands,tellingthemwhattodo.Thenervoussystem'sroleinhungerregulationiscoordinatedbythebrain.Thesensationsofhungerandappetiteareperceivedbythebrain'scortex,thethinking,outerlayer.Deepinsidethebrain,thehypothalamus

monitors

manybodyconditions,includingtheavailabilityofnutrientsandwater.

Tosignalhunger,thephysiologicalneedforfood,thedigestivetractsendsmessagestothehypothalamusbywayofhormonesandnerves.Thesignalsalsostimulatethestomachtointensifyitscontractionsandsecretions,causinghungerpangs(andgurglingsounds).Whenyourbrain'scortexperceivesthesehungersensations,youwanttoeat.Theconsciousmindofthecortex,however,canoverridesuchsignals,andapersoncanchoosetodelayeatingdespitehungerortoeatwhenhungerisabsent.Inamarvelousadaptationofthehumanbody,thehormonalandnervoussystemsworktogethertoenableapersontorespondtophysicaldanger.Knownasthefight-or-lightreaction,orthestressresponse,thisadaptationispresentwithonlyminorvariationsinallanimals,showinghowuniversallyimportantitistosurvival.Example:Whendangerisdetected,nervesreleaseneurotransmitters(神经递质),andglandssupplythecompoundsepinephrine(肾上腺素)andnorepinephrine(去甲肾上腺素).Everyorganofthebodyresponds,andmetabolismspeedsup.Thepupils(瞳孔)oftheeyeswidensothatyoucanseebetter;themusclestenseupsothatyoucanjump,run,orstrugglewithmaximumstrength;breathingquickensanddeepenstoprovidemoreoxygen.Theheartracestorushtheoxygentothemuscles,andthebloodpressurerisessothatthefuelthemusclesneedforenergycanbedeliveredefficiently.Theliverpoursforthglucosefromitsstores,andthefatcellsreleasefat.Thedigestivesystemshutsdowntopermitallthebody'ssystemstoservethemusclesandnerves.Withallactionsystemsatpeakefficiency,thebodycanrespondwithamazingspeedandstrengthtowhateverthreatensit.Inancienttimes,stressusuallyinvolvedphysicaldanger,andtheresponsetoitwasviolentphysicalexertion.Inthemodernworld,stressisseldomphysical,butthebodyreactsthesameway.Whatstressesyoutodaymaybeacheckbookoutofcontrolorateacherwhosuddenlyannouncesapopquiz.Underthesestresses,youarenotsupposedtofightorrun,asyourancientancestorsdid.Yousmileatthe"enemy"andsuppressyourfear.Butyourheartraces,youfeelitpounding,andhormonesstillfloodyourbloodstreamwithglucoseandfat.Yournumber-oneenemytodayisnotasaber-toothedtigerprowlingoutsideyourcavebutadiseaseofmoderncivilization:heartdisease.Yearsoffatandotherconstituentsaccumulatinginthearteriesandstressesthatstraintheheartoftenleadtoheartattacks,especiallywhenabodyaccustomedtochronicunderexertionexperiencessuddenhighbloodpressure.Dailyexerciseaspartofahealthylifestylereleasespent-upstressandhelpstoprotecttheheart.Thenervoussystemandhormonalsystemregulatebodyprocesses,respondtotheneedforfood,governtheactofeating,regulatedigestion,andcallforthestressresponsewhenneeded.KeypointsThefluidsurroundingcells(extracellularfluid)isderivedfromthebloodinthecapillaries:itsqueezesoutthroughthecapillarywallsandflowsaroundtheoutsidesofcells,permittingexchangeofmaterials.Someoftheextracellularfluidreturnsdirectlytothebloodstreambyreenteringthecapillaries.Thefluidremainingoutsidethecapillariesformslymph,whichtravelsaroundthebodybywayoflymphvessels.Thelympheventuallyreturnstothebloodstreamneartheheartwherealargelymphvesselemptiesintoalargevein.Inthisway,allcellsareservedbythecardiovascularsystem.Thefluidinsidecells(intracellularfluid)providesamediuminwhichallcellreactionstakeplace.Itspressurealsohelpsthecellstoholdtheirshape.Theintracellularfluidisdrawnfromtheextracellularfluidthatbathesthecellsontheoutside.BloodCirculationAllthebloodcirculatestothelungs,whereitpicksupoxygenandreleasescarbondioxidewastesfromthecells.Thenthebloodreturnstotheheart,wherethepumpingheartbeatspushthisfreshlyoxygenatedbloodfromthelungsouttoallbodytissues.Asthebloodtravelsthroughtherestofthecardiovascularsystem,itdeliversmaterialscellsneedandpicksuptheirwastes.BloodCirculationofNewbornBabyAsitpassesthroughthedigestivesystem,theblooddeliversoxygentothecellsthereandpicksupmostnutrientsotherthanfatsandtheirrelativesfromtheintestinefordistributionelsewhere.Lymphaticvesselspickupmostfatsfromtheintestineandthentransportthemtotheblood.Allbloodleavingthedigestivesystemisrouteddirectlytotheliver,whichhasthespecialtaskofchemicallyalteringtheabsorbedmaterialstomakethembettersuitedforusebyothertissues.Later,inpassingthroughthekidneys,thebloodiscleansedofwastes.Notethatthebloodcarriesnutrientsfromtheintestinetotheliver,whichreleasesthemtotheheart,whichpumpsthemtothewaitingbodytissues.Water,Nutrients,andtheBloodToensureefficientcirculationoffluidtoallyourcells,youneedanamplefluidintake.Thismeansconsumingsufficientwatertoreplacethewaterlosteachday.Cardiovascularfitnessisessential,too,anditrequiresattentiontobothnutritionandphysicalactivity.Healthyredbloodcellsalsoplayarolefortheycarryoxygentoalltheothercells,enablingthemtousefuelsforenergy.Sinceredbloodcellsarise,live,anddiewit

温馨提示

  • 1. 本站所有资源如无特殊说明,都需要本地电脑安装OFFICE2007和PDF阅读器。图纸软件为CAD,CAXA,PROE,UG,SolidWorks等.压缩文件请下载最新的WinRAR软件解压。
  • 2. 本站的文档不包含任何第三方提供的附件图纸等,如果需要附件,请联系上传者。文件的所有权益归上传用户所有。
  • 3. 本站RAR压缩包中若带图纸,网页内容里面会有图纸预览,若没有图纸预览就没有图纸。
  • 4. 未经权益所有人同意不得将文件中的内容挪作商业或盈利用途。
  • 5. 人人文库网仅提供信息存储空间,仅对用户上传内容的表现方式做保护处理,对用户上传分享的文档内容本身不做任何修改或编辑,并不能对任何下载内容负责。
  • 6. 下载文件中如有侵权或不适当内容,请与我们联系,我们立即纠正。
  • 7. 本站不保证下载资源的准确性、安全性和完整性, 同时也不承担用户因使用这些下载资源对自己和他人造成任何形式的伤害或损失。

评论

0/150

提交评论