




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。
最新文档
- 产品发布活动方案
- 电力系统自动化控制知识考点解析
- 高性能集成电路设计技术指南
- 餐饮业营养均衡餐饮策划与实施方案
- 贵州2025年贵州贵阳学院招聘7人笔试历年参考题库附带答案详解
- 甘肃2025年甘肃省统计局所属事业单位招聘4人笔试历年参考题库附带答案详解
- 湖北2025年湖北美术学院专项招聘专任教师40人笔试历年参考题库附带答案详解
- 安全教育与春季传染病
- 膝关节阶梯化治疗
- 小学生关于旅游
- 2025年日语n2考前试题及答案
- 2025年山西同文职业技术学院单招综合素质考试题库带答案
- 防洪防涝知识培训课件
- 2025年安徽卫生健康职业学院单招职业技能测试题库审定版
- 2025年01月中国疾控中心信息中心公开招聘1人笔试历年典型考题(历年真题考点)解题思路附带答案详解
- 安徽2025年安徽汽车职业技术学院教职工校园招聘笔试历年参考题库附带答案详解
- 中央2025年中国科协所属单位招聘社会在职人员14人笔试历年参考题库附带答案详解-1
- 2025年中国移动通信集团贵州限公司招聘高频重点模拟试卷提升(共500题附带答案详解)
- 2025年江苏电子信息职业学院高职单招职业适应性测试近5年常考版参考题库含答案解析
- 临床基于高级健康评估的高血压Ⅲ级合并脑梗死患者康复个案护理
- 2024年全国统一高考英语试卷(新课标Ⅰ卷)含答案
评论
0/150
提交评论