英语听力教程LTW2Unit

Unit7

AboutYourselfPartIGetting

readyPartIIThedigestivesystemanddiarrheaPartIIIImmunityPartIVMoreaboutthetopic:WhyDoICatchColds?PartVMemorytest:DentalHealthPartVIWatchandenjoyListenThisWayBook21/47PartIGettingreadyOurbodyismadeupofdifferentparts,suchasface,handsandfeet.Bodywordshavebeenwidelyusedfigurativelyinsomephrases.Andthesephrasesoftencreateveryvividimages.*figuratively象征性地，比喻地2/47A.Thefollowingwordswillappearinthisunit.Listencarefullyandstudythedefinitions.1.grindtoahalt:停顿2.abdomen:腹部3.coilup:盘卷，盘绕4.dehydrate:脱水5.contaminatedfood:不洁食物6.bacteria:细菌7.virus:病毒8.reserve:贮备9.lash:猛击10.infect:传染，感染11.gum:齿龈12.wig:假发3/47B.Youaregoingtohearseveralshortdialogues.Payattentiontothenumbersandthebodywordsinthephrases.Thenguessthemeaningofthesephrases.4/471.A:Doyouknowhowmany_____you’vegot?B:Howmanyteeth?Ooh,ooh.____?More?(A:Yes)___?A:Yes.2.A:Doyouknowhowmanybonesthereareinyourbody?B:Howmanybones?I’lltakeaguess.____.A:____.3.A:Howoftendoesyourheartbeat?B:__timesaminute.A:No,___timesaminute.20670981533224teeth5/474.Bob:Doyouknowwhatthebossthinksyoushoulddo,Billy?Billy:Justyoukeepyourgreat_____outofthis,Bob,willyou?(Meaning:_____________)5.Anne:StevenKent,Inever,neverwanttoseeyouinmylifeagain.Steven:Ohno.Mary:Youreallyhaveputyour_____init,haven’tyou?(Meaning:___________________________________________)6.Kate:Dave!Canyougivemea______,please?Dave:What?Kate:Isaid“canyougivemea_____?”Dave:Allright,I’mcoming.Noneedtoshout.(Meaning:__________)askforhelphandcauseembarrassmentbydoingorsayingsthtactlessfootnotinterfereinnosehand*interferein干涉，干预*tactless

不机智，拙笨6/477.Max：Arethereanyjobsgoinginyourcompanythen,foranintelligent,hard-workingyoungmanlikemysonJulian?Frank:No,Ihaven’theardofanyatallrecently.Max:Well,couldyoukeepyour_____open,justincase?(Meaning:_____________)8.Carol:HaveyouheardaboutMaggiethen?Norma:Maggie?MaggieThatcher?Carol:No.MaggieBrown.She’sinloveagain.Norma:Ohnotagain.Whowiththistime?Carol:Withherboss.______overheelsinlovewithhim,sheis.(Meaning:__________)listenwithcare*justincase以防万一Headearscompletely*heel脚后跟7/479.Nick：HaveyoueverlentanymoneytoMick?Jill:Mick?Huh!Iwouldn’tlendhimanyifIwereyou.Nick:Whynot?Doesn’thepayitback?Jill:No.Never.He’suptohis______indebts.(Meaning:________________)10.Liz:She’saverygooddoctor.Neverlooksatherwatch.Nevercomplains.Nothing’stoomuchtroubleforher.Pat:Iknow,yeah.Notmanylikeherabout.She’sall______,really.All_______.(Meaning:_____________________)withthedeepestdevotiondeeplyinvolvedinheartneckheart8/47C.Nobody'sreallysurewhypeoplegobald,butsomescientistsbelievethatpeoplemayinheritbaldness.Ifyouareinterested,checkoutyourmother'sfather.Yourhairlinemaylooklikehiswhenyougetolder.Nowlistentoaradiophone-in.Completethefollowingchart.*gobald谢顶，秃顶*inherit继承*hairline发际线9/47Caller’snameProblemCaller’sdoctor’sopinionSolutionAdvice*hereditary遗传*shampoo香波，洗发水*thinpatch头发稀少区域*falsehairpiecething=wig假发don’tcombitover;don’twearanyfalsehairpiecethingsnotalothecandoaboutit;trytoacceptnothinghecandoaboutit;hereditarylosinghairJimBaillieAudioscriptHomepage10/47PartIIThedigestivesystemanddiarrheaThehumanbodyisahighlycomplexself-generator,thatistosay,provideditisgiventherightfuel,itiscapableofbothcuringandwardingoffdisease.Thefoodweeathelpstogiveusenergy.Ithasalongjourneytomakebeforeallitsgoodnesshasbeentakenintoourbody.Thefoodtakesuptosixhourstobedigestedinthestomach,dependingonthesizeofthemeal.Thecompletedigestiveprocesstakesabout24hours.Butsometimesthesystemcangowrong.*digestivesystem消化系统*diarrhea腹泻，拉肚子*self-generator自愈体*warding

off阻挡（疾病）*digested消化*stomach胃*completedigestiveprocess整个消化过程11/47A.Youaregoingtohearatalkonthedigestivesystemanddiarrhea.Whilelisteningforthefirsttime,addmorekeywordsinthenotescolumn.Afterthesecondlistening,matchcolumnAwithcolumnBwiththehelpofthenotes.*inexpertly不熟练地，外行地*over-taxed税负过重，过分透支*insufficientlyused使用不妥*rusty迟钝，衰退*sluggish懒怠，无活力*clogged阻塞，不通畅*mechanism机械装置*rawmaterial原材料*tissue人体组织*squeeze挤压*muscle肌肉*thewalloftheintestine肠壁*feces粪便*bowel肠道*clearup治愈，痊愈*fluid水分*dehydrated/dehydration脱水12/47ColumnAColumnB1.gutsymptoms__absorbingdigestedfoodintobloodstream__contaminatedfood2.thedigestivesystem__drinkingenough__alongtubecoilingupintheabdomen3.causesofdiarrhea__carryingawaywasteproducts__constipation4.jobsofthedigestivesystem__infectionbyvirusesorparasites__breakingdownfood5.treatmentfordiarrhea__addingenzymes__diarrhea4253414314*肠道症状*bloodstream

血流*wasteproducts排泄物*便秘*感染*寄生虫*病毒*分解食物*enzyme酶Audioscript13/47B．Nowtrythis:listentoamoreauthenticversionofthetalk.Focusonthecausesandtreatmentsofdiarrhea.Completethestatements.14/47CausesofdiarrheaThereareinfections,andthisis____________,whichiscausedbysomesortofbacteriaororganisms.Somefoods_________mightirritate_______andtendtogiveyoudiarrhea.Somepeoplewhenthey______________and_____________________tendtogetdiarrhea.Peoplewhosufferfromtheirritablebowelsyndrometendtogettummypainsand________.*foodpoisoning

食物中毒*bacteria细菌*organisms生物体，有机体*irritate刺激，使过敏，使发炎*irritablebowelsyndrome肠激惹综合征*tummypain肚子痛thegutthemselvesfoodpoisoningdiarrheastressedaboutsomethinggetverynervous15/47TreatmentofdiarrheaMostattacksofdiarrheaarenot_______andthey________bythemselveswithin_____________.Themostimportantthingisto______________.Itisbetternotto____________andnottoworryaboutthat.Ideally,thefluidsyoudrinkshouldcontainalittlebitof______________.Youcangetspecialrehydratingfluids,whichare_____________.Youcangetyourownfluidsbyaddingjustateaspoonfulof________________________.sugarandapinchofsaltspeciallymixedsaltandsugareattoomuchdrinklotsoffluidoneortwodaysclearupserious*attacksofdiarrhea腹泻病发*rehydratingfluids再水合剂*apinchof一小撮AudioscriptHomepage16/47PartIIIImmunityTheenvironmentcontainsmanypotentiallydestructivemicroorganisms.Itisimpossibleforustoavoidcontactwithmicrobes.That'swhyourbodyisconstantlyunderattackfrominvadinggermsandinfections.Thenwhydon'twesufferfromconstantillness?Dowehaveourowndefensesystem?*immunity免疫力*microorganisms微生物*microbes微生物，细菌17/47A．Thefollowingwordsandphrasesareusedinadiscussionontheimmunesystem.Listentothewordsandphrasesfirst.Studythedefinitionscarefully.1.germ:微生物，细菌2.defensesystem:防御系统3.cell:细胞4.whitebloodcell:白细胞，白血球5.molecule:分子6.bonemarrow:骨髓7.antibody:抗体8.measles:麻疹9.polio:小儿麻痹症10.tuberculosis:肺结核11.AIDS:艾滋病18/47B．Nowlistentothefollowingdiscussion.Whilelisteningforthefirsttime,addmorekeywordsintheleft-handcolumn.Afterthesecondlistening,answerthequestions.19/47NotesQuestionsimmunity:defensesystem1.Sincewehavetheimmunesystem,whydowestillneedvaccinations?______________________________________________________________________headquarters:bloodtroops:cells

reserve:bone

marrow

whitecells:gobble

up;memorynotworkingwell

overactive—

underactive—2.Howdoesavaccinationwork?_______________________________________________________________________________________________________________________________________________________________________________Becausetherearesomethingswhich we’renotnaturallyimmuneto.Aversionofanillnessisgivento thebody,andthebodythinksthatitisactuallybeinginfectedwiththatinfection.Thenexttimeitseesit,thebodycanrespondveryquickly.*免疫系统*疫苗接种

*细胞

*不够活跃*过于活跃*狼吞虎咽

*骨髓

20/47NotesQuestionsvaccination:notimmune;remember;versionofillness3.Canweproducevaccinesforanydisease?Giveanexample.____________________________________________________________AIDS:HIV;attackimmunesyst.;changeeasily4.WhyisitsodifficulttoattackAIDS?____________________________________________________________________________________________________________________________________________________________________________________*protein蛋白质*invader入侵者*comeintoplay开始起作用*turnon突然攻击*multiple-sclerosis多发性硬化TheHIVvirus,whichcausesAIDS,attacksthehumanimmunesystem.Andthevirusitselfcanchangeveryeasily.It’sverydifficulttofindavaccinewhichcanrecognizealltypesofHIV.No.Wecan’tproduceavaccinefor AIDSforinstance.*疾病种类Audioscript21/47C.Nowtrythis:listentoamoreauthenticversionofthediscussion.Completethediagram.Thenputthenumberofeachphrasebelowintheproperplace.*familydoctor家庭保健医生*backup后援，援助*tiedup忙得不可开交*makeup结构*atgreaterrisk处于更危险境地22/47bloodmorelikelytobeinfectedinvadersinvaders23/47thevirusthatcausesAIDSrememberingthechemicalmakeupofinvadinggermsandattackingthemveryquicklyfightinginvadingdiseasedestroyingthebody’simmunesystemprotectingthebodyagainstspecificinfectionsputtingthebodyatgreaterriskfromothercommoninfections1.2.3.4.5.6.theimmunesystem________________________________

vaccination______________________________HIV____________________________532641AudioscriptHomepage24/47PartIVMoreaboutthetopic:WhyDoICatchColds?Acoldisamildviralinfectiousdiseaseofthenoseandthroat,theupperrespiratorysystem.Symptomsofacoldincludesneezing,sniffing,running/blockednose,scratchy,sore,orphlegmythroat,coughing,headache,andageneralfeelingofunwellness;theylastbetween3to10days,withresidualcoughinglastingupto3weeks.Itisthemostcommonofalldiseases,infectingsubjectsatanaverageofslightlyoveroneinfectionperyearwithgreaterthan3infectionsperyearnotuncommoninsomepopulations.*viralinfectiousdisease病毒感染类疾病*upperrespiratorysystem上呼吸系统*sneezing打喷嚏*sniffing抽鼻子*running/blockednose流鼻涕/鼻塞*scratchy/sore/phlegmythroat咽喉刺痒/疼痛/多痰*unwellness不舒适*residualcoughing感冒好了之后咳嗽*subjects病人，患者25/47Thefollowingmonologueisaboutacommondisease—cold.Listencarefullyandsupplythemissinginformation.26/47

Virusesaremostdefinitelygoingtogetyou.Andwhentheydo,theywillgiveyouanything,fromacoldtoEbola.Andyet,________,viruseshavenolife_________.Sowhydotheycausesomuchtrouble?______________,whydoIcatchcolds?Seethatguywiththe_______nose.Whenhe________,______

dropletswillflytwelvefeetintotheair,infectingupto____people.Youshouldhave______.Acoldvirusjustcan’tlivewithoutyou.Withnocellsofitsown,itneedsto________yourcellsandreplicate.Here’ssomethingtothinkabout.takeoverducked15040,000sneezesblockedMoretothepointoftheirowntechnically*Ebola埃博拉*droplet小滴*replicate复制technically严格意义上Moretothepoint说得更确切些*duck低头27/47

Theviruscanonlytravelaroundinsideablobofmucus.Andthatmeanswheneveryoucatcha_______,someoneelse’ssnothasbeenupyournose.Anyway,your_____________isconstantlyontheprowlforattackerslikethese.Ifitwasn’t,youcould__________

fatalpneumonia.So,whenitspotsaviralinvasion,itgrabsa_______andtakesittothenearestlymphnode,homeofyourkillerTcells.Here,aTcellfirstidentifiestheinvaderandthendeploysanarmyoftailor-madeimmunecellstoyournose.Theseprovidespecialist________forthestandardimmunecellsalreadyfightingyourcold.Yournosehasbecomeabattleground.backupsampleendupwithimmunesystemsniffle*ablobofmucus一滴粘液*snot鼻涕*ontheprowl徘徊，逡巡*fatalpneumonia致命肺结核*spot发觉*lymphnode淋巴结*deploy布署*tailor-made量身定制*sniffle鼻塞，感冒28/47

Meanwhile,tostopinfectionspreadingtoyourlungs,you’remanufacturingadailypintofmucus.Thissnotgivesyoua________.Whilethevirusirritatesyournose,soyouhaveto_____itaround45timesaday.Beatingacoldtakesyouaboutsevendaysandyou’llcatchaboutfourayear.Thisis_____________forthecoldvirus.Ithopsonplaneswithitshuman_____,visitsnewcitiesandfindshundredsofnewhomeswitheverysneeze.Asitreplicates,itmutates.Sobythenextyearitmaybebackinadifferentform.hoststhegoldenageblowheadache*adailypintof每日一品脱*hop跳上（飞机）*mutate变异Homepage*blow擤（鼻涕）29/47PartVMemorytest:DentalHealthIndifferentcountriesandamongdifferentpeoples,thereisawiderangeoffoodswhichcanbecombinedtoprovideabalanceddiet.Thetypeofdietapersonadoptsdependsonwhatfoodsareavailable,howmuchtheycostandonreligiousandculturalbeliefs.Butinordertoenjoythedeliciousfoods,youmusthaveastrongsetofteeth.Soitisveryimportanttokeepyourteethhealthy.*balanceddiet均衡饮食*astrongsetofteeth一口好牙30/47Thefollowingpassageisaboutdiseasesoftheteethandgums,andwaystopreventandtreatthem.Listencarefullyandsupplythemissinginformation.*theMaya玛雅人〔中美洲印第安人，在美洲被西方发觉前已经有高度文明〕玛雅文明，是分布于现今墨西哥东南部、危地马拉、洪都拉斯、萨尔瓦多和伯利兹5个国家丛林文明。即使处于新石器时代，却在天文学、数学、农业、艺术及文字等方面都有极高成就。与印加帝国及阿兹特克帝国并列为美洲三大文明（阿兹特克帝国与玛雅文明位于中美洲；印加帝国位于南美洲安第斯山一带）。31/47AncientEgyptians:earliest_______ofdentaltreatment—treating___________byusingasubstancemadeof_______________.

—earliestknown________totreattoothproblems—livingabout______yearsago,knownasa“_______________”Chinese:5000yearsago—treatingtoothpainby___________1300yearsago—__________intheteethwithamixtureofthemetals

—___________________

Maya:makingteeth______byplacingpiecesof_____________onthemstoneandmetalpersonspicesandonionsgumswellingrecordacupuncturedoctorofthetooth5000prettymercury,silverandtinfillingholes*牙龈肿痛*香料/洋葱*水银(贡)，银，锡*补牙齿蛀洞*针灸32/47AncientRomans:yearsago—making_________to_______thosethathadbeenlostEuropeans:

5th–15thcentury—______________performingservicesincluding_________,_________andtreatingmedicalconditions14th–15thcentury—______________improvedFrench:1700s—PierreFauchard:thefatherof______________

—TheSurgeonDentist:thefirstbookabout_____________

dentalsciencemoderndentistrydentaltreatmentbarber-surgeonspullingteethcuttinghairreplacefalseteeth*假牙*牙医学*牙科医术*(旧时)兼做外科医生和牙医剪发师AudioscriptHomepage33/47PartVIIWatchandenjoy*flakeoff剥落*overlap叠盖*tightly-packedrooftiles重重合叠屋顶瓦片*waterproof防水*formidablebarrier主要屏障*flexible柔韧灵活*inertcoating惰性表层*vitalfunction维持生命主要机能*heat-sensitivecamera热敏感摄像机*internalorgan内部器官

*sweatgland汗腺

*contract收缩*evaporate蒸发*finelytunedtechnology精美技术*robust强壮*mesh网状物*collagenfiber胶原纤维*bloodvessel血管*sever切断*healingkit治愈装备*platelet血小板，凝血细胞*scab痂，疮痂

34/471._____Thebiggestorganinthehumanbodyisskin.2._____Thepartoftheskinthatyoucanseeismadeupoflivingcells.3._____Pregnantwomenproduceahormonethatallowstheirskintostretchtotwiceitssize.4._____Abodyworkingflatoutcanexpelthreepintsofsweatperhour.5._____AstrandofcollagenisstrongerthanasteelwireofthesamedimensionsTFTFT*2.(F)Thepartoftheskinthatyoucanseeismadeupofdeadcells.*4.(F)Abodyworkingflatoutcanexpeltwopintsofsweatperhour.VideoscriptHomepage*荷尔蒙*汗水*排出*竭尽全力*一股胶原纤维*尺寸35/47Radiopresenter:Allright.Thankyouforthatcall,Rosemary.Wegonow,Ithink,toGlasgowandournextcaller,er,JimBaillie.Hello,Jim.Jim:Hello?Radiopresenter:Hello,Jim.What’syourproblem?Jim:Er…wellI’mer…beginningtolosemyhair.Er,Iwenttothedoctor,buthejustsaidtherewasnothingIcandoaboutit.Hesaiditwasprobablyhereditary.Myfatherwasbaldbythetimehewasthirty.Maurice:Hello,Jim.Andhowoldareyou?Jim:Me.I’mtwenty-eight.Maurice:Andareyoulosingalotofhair,then?Jim:Well,itcomesoutalotwhenIcombmyhairandyoucanseeathinpartonthetopofmyhead.Maurice:Anddoesthatreallyworryyou,Jim?Jim:Well.Idon’tlikeit.It’sold…youknow…looksold…Idon’twanttolooklikeamiddle-agedmanattwenty-eight.AndIwonderediftherewassomespecialshampooIshoulduse…ifyoucouldtellmeonethatIshouldbuy…somethinglikethat…youknow…tostopitgettingworse.Maurice:Well,youknow,Jim,tobehonestwithyouthere’snotreallyalotyoucandoaboutit,actually,I’mafraid.Imean,baldnessisoneofthosethingsthat,inmyexperience,youjusthavetotrytoaccept.Somemenfinditmoredifficulttoacceptbaldnessthanothers…

36/47Tessa:Thereisonepieceofadvice,though,Jim,andthat’sdon’ttrytocombyourhairoverthebaldorthinpatch.Don’ttrytohideit.Whateveryoudo,don’tcombitoverbecausethatusuallylooksridiculous.Andtheotherthingthatusuallylooksridiculousisamanwithawig.Don’tletanyonepersuadeyoutobuyoneofthosefalsehairpiecethings,becausetheyusuallylookmuchworsethanabaldman.Iactuallythinkbaldmencanlookveryattractive.Myhusband’sbaldandIthinkitreallysuitshim.

Audioscript37/47Ourbodyismadeupofthousandsofdifferentparts.Allthesepartsworktogethertokeepusaliveandtohelpusmovearound.Thepartsofthehumanbodyarelikethepartsofaverycomplicatedmachine.Likeanyothermachine,however,ifitisinexpertlycaredfor,over-taxedorinsufficientlyused,itwillbecomerusty,sluggishorcloggedandpartsofitsmechanismmayevengrindtoahalt.Thatiswhyitissoimportanttokeepeverypartofthehumanmachinehealthyandproperlycaredfor.Tokeepingoodrunningorder,thebodyrequirestherawmaterialsforgrowthandthereplacementoftissueswhennecessary.Ourbodiesburnfoodlikefueltoproducetheenergyweneed. Thehumandigestivesystemisabitlikeaverylongtube,butit’salotmorecomplex.It’sseveralmeterslong,andmostofitiscarefullycoiledupinourabdomen.Ithasseveralimportantjobstodo. First,itmustdigestorbreakdownourfood.Digestionstartsthemomentfoodentersourmouth.Thenitcontinuesasthefoodissqueezedalongthegutbymusclesinthewalloftheintestine.Asthefoodtravelsthroughthegut,naturalchemicalscalledenzymesareaddedtoit,whichhelpbreakdownthefood.Thenthisdigestedfoodandwatermustbeabsorbedfromthegutintoourbloodstreamsothatitcanbeusedbythebody.Finally,thegutmustcarryawayanywasteproductsintheformoffeces.

38/47Usuallyourintestinedoesallthesethingsveryefficiently.Butsometimesthingscangowrong.Probablythemostcommongutsymptomsarediarrheaandconstipation. Withdiarrhea,thefoodandwatertravelstooquicklythroughtheintestine,oftenmakingthefeceswatery,andmakingitnecessarytoopenthebowelsmorefrequently. Therearelotsofcausesofdiarrhea.Probablythecommonestcausesofdiarrheaarecontaminatedfoodorwater,andinfectioncausedbyvirusesorparasites. Manycasesofdiarrheaclearupwithinafewdayswithoutanyspecialmedicines.Butthebodylosesalotoffluidthroughdiarrhea,sothereisaveryrealriskofthebodydryingoutorbecomingdehydrated.Becauseofthisriskofdehydration,thebesttreatmentfordiarrheaissimplytomakesureyouaredrinkingenough.Avoidingdehydrationinthiswaycanbealifesaver.

Audioscript39/47Therearelotsofdifferentcausesofdiarrhea.Um,thereareinfectionsthatcanhappen,andthisisfoodpoisoning,ifyoulike,whereinyourfoodyoueatsomesortofbacteriaororganisms,whichinfectyou.Somefoodscanjustirritatethegutandtendtogiveyoudiarrhea,althoughtheyarenotinfected.It’sjustthefooditself(that)mightirritateyoursystem.Somepeople,iftheygetverynervousandstressedaboutsomething,findtheytendtogetdiarrhea,somethingcalledtheirritablebowelsyndromewheresomethinggoeswrongwiththewaythegutworks.Andpeoplethatsufferfromthistendtoget,um,tummypains,andtheygetsometimesdiarrhea,sometimesconstipation.Allsortsofcauses.Mostattacksofdiarrhea,um,particularlyinadults,arenotseriousandtheyclearupbythemselveswithinonetotwodays.Themostimportantthingistodrinklotsoffluid,becauseifyouhavegotdiarrhea,you’reobviouslylosingalotoffluid.Andsoit’sbetterreallynottoeattoomuch,nottoworryaboutthat,buttomakesureyoudrinkplentyoffluid.Andideally,theyshouldhavealittlebitofsaltandsugarin.Youcangetspecialrehydratingfluids,whicharespeciallymixed.Butifyouwanttomakeyourownbyaddingjustateaspoonfulofsugarandapinchofsalt,thenit’sobviouslyperfectlyreasonabletodothat.Audioscript40/47Thehumanbodyisconstantlyunderattackfrominvadinggermsandinfections.Andtheonlyreasonwedon’tsufferfromconstantillnessisourbodieshavetheirowndefensemechanismtofightoffdisease.Thisresistancetoinfectioniscalledimmunity.A:Howdoesimmunitywork?B:Well,theimmunesystemisthebody’sownsecretarmy,whichfightsinfection.Anditconsistsofawholerangeoftroops,soldiers,theircellsandtheirmolecules.Nowtheheadquartersofthisarmyisreallytheblood.That’swhereitdoesmostofitsfighting.Andsometimesitneedssomereserve,andthatcomesfromthebonemarrow.That’swheretheimmunecellsaremade.A:Sotherearemanydifferentkindsofcells,differentkindsofmoleculesintheimmunesystem.Iguessedtheonesthatwe’reprobablymorefamiliarwitharewhitebloodcells.B:That’sright.Whitebloodcellsformamajorpartofthebody’sdefense.Buttherearealsoantibodiesintheirlife,moreproteins.Theyjustlashontotheinvaders.Thewhitecellscansometimesactuallygobbleupinvaders.Thecleverthingisthatoncetheinfectionhasattackedourbody,theimmunesystemseemstohaveamemoryoftheinvader,sothatthenexttimeitseestheinvaderitcanattackveryquickly.A:Therearesomethingswhichwe’renotnaturallyimmunetoandthat’swherevaccinationcomesin,isn’tit?B:Exactly.Vaccinationplaysonthebody’sabilitytorememberinfection.Sowhathappensisthatsomeoneisgivenaversionofanillness,forinstance,measlesorpolio,ortuberculosis,andthebodythinksthatitisactuallybeinginfectedwiththatinfection.Andthenexttimeitseesit,thebodycanrespondveryquickly.Allthetroopsofitsimmunesystemcancomeintoplay.41/47A:Nowsometimestheimmunesystemdoesn’tworkverywell,doesit?B:No.It’saremarkablycomplexsystem.Andsometimesitcangowrong.Eitheritcanbeoveractive,soitactuallystartstoattackourownbodyself,oritcanbeunderactivesometimes,andwearemorelikelytobeinfectedinthatsituation.A:Arethereanyimportantillnesseswhichresultfromtheimmunesystemsothatit’sturningonourbodiesthemselves?B:Thereare.Oneexamplewouldbeadiseaselikemultiple-sclerosis,wherethebody’sownimmunesystemattackstheliningofnerves,whichmeansthatpeople’snervesdon’tworkproperly.A:We’reabletoassistthebodyinitsfightagainsttheillnessinmanycases,buttherearesomediseaseswhichwedon’tseemtobeabletoproduceavaccinefor.AIDSisoneofthem.Whynot?B:TheproblemisAIDS,whichiscausedbytheHIVvirus,attacksthehumanimmunesystem,whichmeansthatournormaldefensesaren’ttheretofightoffthatinfection.TheotherproblemwithtryingtoproduceavaccineagainstHIVorAIDSisthatthevirus,HIV,canchangeitselfsoeasily.That’sverydifficulttofindavaccinewhichcanrecognizeallthedifferenttypesofHIV.Soonevaccinemaybeeffectiveagainstonetypeofthevirusbutitmayabsolutelybenogoodforanothertype.Audioscript42/47Presenter:Thehumanbodyisconstantlyunderattackfrominvadinggermsandinfections.Andtheonlyreasonwedon’tsufferfromconstantillnessisourbodieshavetheirowndefensemechanismtofightoffdisease.Thisresistancetoinfectioniscalledimmunity.AndherewithmetodiscusshowitworksisGrimeEaston.Heisafamilydoctor,andamemberoftheScienceInIt”hereintheBBCWorldService.Grime,howdoesimmunitywork?Grime:Well,theimmunesystemisthebody’sownsecretarmy,ifyoulike,whichfightsinfection.Anditconsistsofawholerangeoftroops,soldiers,theircellsandtheirmolecules.Um,nowtheheadquartersofthisarmyisreallytheblood.That’swhereitdoesmostofthefighting.Andsometimesitneedssomereserve,somebackup,andthatcomesfromthebonemarrow.That’swheretheimmunecells’factoriesare.Presenter:Sotherearemanydifferentkindsofcells,anddifferentkindsofmoleculestiedupintheimmunesystem.Iguessedtheonesthatwe’reprobablymorefamiliarwitharewhitebloodcells.Grime:That’sright.Thewhitebloodcellsformamajorpartofthebody’sdefense.Buttherearealsoantibodiesintheirlife,moreproteins,whichjustlashontotheinvaders.Um,but,asyousay,thewhitecellscansometimesactuallygobbleupinvaders.Sothecleverthingisthatoncetheinfectionhasattackedourbody,theimmunesystemseemstohaveamemoryoftheinvader,sothatthenexttimeitseest