医学专业英语翻译及答案

PAGEPAGE34Inthispassageyouwilllearn:

Chapter1Passage1HumanBodyClassificationoforgansystems2.Structureandfunctionofeachorgansystem3.AssociatedmedicaltermsTounderstandthehumanbodyitisnecessarytounderstandhowitspartsareputtogetherandhowtheyfunction.Thestudyofthebody'sstructureiscalledanatomy;thestudyofthebody'sfunctionisknownasphysiology.Otherstudiesofhumanbodyincludebiology,cytology,embryology,histology,endocrinology,hematology,immunology,psychologyetc.了解人体各部分的组成及其功能，对于认识人体是必需的。研究人体结构的科学叫解剖学；研究人体功能的科学叫生理学。其他研究人体的科学包括生物学、细胞学、胚胎学、组织学、内分泌学、血液学、遗传学、免疫学、心理学等等。Anatomistsfinditusefultodividethehumanbodyintotensystems,thatis,theskeletalsystem,themuscularsystem,thecirculatorysystem,therespiratorysystem,thedigestivesystem,theurinarysystem,theendocrinesystem,thenervoussystem,thereproductivesystemandtheskin.Theprincipalpartsofeachofthesesystemsaredescribedinthisarticle.解剖学家发现把整个人体分成骨骼、肌肉、循环、呼吸、消化、泌尿、内分泌、神经、生殖系统以及感觉器官的做法是很有帮助的。本文描绘并阐述了各系统的主要部分。Theskeletalsystemismadeofbones,jointsbetweenbones,andcartilage.Itsfunctionistoprovidesupportandprotectionforthesofttissuesandtheorgansofthebodyandtoprovidepointsofattachmentforthemusclesthatmovethebody.Thereare206bonesinthehumanskeleton.Theyhavevariousshapes-long,short,cube-shaped,flat,andirregular.Manyofthelongboneshaveaninteriorspacethatisfilledwithbonemarrow,wherebloodcellsaremade.骨骼系统由骨、关节以及软骨组成。它对软组织及人体器官起到支持和保护作用，并206根骨头。骨形态不一，有长的、短、立方的、扁Ajointiswherebonesarejoinedtogether.Theconnectioncanbesoclosethatnomovementispossible,asisthecaseintheskull.Otherkindsofjointspermit movement:eitherbackandforthinoneplane-aswiththehingejointoftheelbow-ormovementaroundasingleaxis-aswiththepivotjointthatpermitstheheadtorotate.Awiderangeofmovementispossiblewhentheball-shapedendofonebonefitsintoasocketattheendofanotherbone,astheydointheshoulderandhipjoints.关节把骨与骨连接起来。颅骨不能运动，是由于骨与骨之间的连接太紧密。但其它的关节可允许活动，如一个平面上的前后屈伸运动，如肘关节；或是绕轴心旋转运动，如枢轴点允许头部转动。如果一根骨的球形末端插入另一根骨的臼槽里，大辐度的运动（如肩关节、髋关节）即成为可能。Cartilageisamoreflexiblematerialthanbone.Itservesasaprotective,cushioninglayerwherebonescometogether.Italsoconnectstheribstothebreastboneandprovidesastructuralbaseforthenoseandtheexternalear.Aninfant'sskeletonismadeofcartilagethatisgraduallyreplacedbyboneastheinfantgrowsintoanadult.软骨是一种比一般骨更具韧性的物质。它是骨连结的保护、缓冲层。它把肋骨与胸骨连结起来，也是鼻腔与内耳的结构基础。一个婴儿的骨骼就是由软骨组成，然后不断生长、骨化，使婴儿长大成人。Themuscularsystemallowsthebodytomove,anditscontractionsproduceheat,helpsmaintainaconstantbodytemperature.Striatedmusclescanbeconsciouslycontrolled.Theendsofthesemusclesareattachedtodifferentbonesbyconnectivetissuebandssothatwhenthemusclecontracts,onebonemovesinrelationtotheother.Thismakesitpossibletomovethewholebody,aswhenwalking,ortomovejustonepartofthebody,aswhenbendingafinger.Contractionsoftheheartandsmoothmusclesarenotunderconsciouscontrol.Smoothmusclesarefoundinthewallsoforganssuchasthestomachandtheintestinesandservetomovethecontentsoftheseorgansthroughthebody.肌肉系统使躯体运动，肌肉收缩产生的热有助于维持一个恒定的体温。人体能够有意识地控制条纹肌。结缔组织使肌肉末端附着于不同的骨面上，所以当肌肉收缩时，两骨彼此靠近而产生运动。这也就使整个人体可以运动起来，器官壁内层的平滑肌，如胃肠壁的平滑肌把胃肠中的物质运送到全身。Thecirculatorysystem.Allpartsofthebodymusthavenourishmentandoxygeninordertofunctionandgrow,andtheirwasteproductsmustberemovedbeforetheyaccumulateandpoisonthebody.Thecirculatorysystemdistributesneededmaterialsandremovesunneededones.Itismadeupoftheheart,bloodvessels,andblood,whichtogethermakeupthecardiovascularsystem.Thebloodisalsopartofthebody'sdefensesystem. Ithasantibodiesandwhitebloodcellsthatprotectthebodyagainstforeigninvaders.和氧气来使之发挥功能和生长，也需要在这些器官所产生的废物积聚而危害生命之前将其排除。循环系统运送有用物质，排泄废物。心血管系统是循环系统的组成之一；心血管系统包括心脏、血管及血液。血液也是机体防御系统的一个部分，血液中有抗体及白细胞来防止机体受到外来的侵袭。Theheartisamusclethatisdividedintotwonearlyidenticalhalves:onehalfreceivesbloodfromthelungsandsendsittotherestofthebody,theotherhalfsendsbloodthathastraveledthroughthebodybacktothelungs.Whentheheartmusclecontracts,thebloodisforcedoutintoarteriesandenterssmallcapillaries.Bloodreturnstotheheartthroughveins. 心脏是一块被分送血液返回心脏。Alsofunctioningincirculationisthelymphaticsystem.Someofthefluidthatsurroundscellsdoesnotreenterthebloodvesselsdirectly.Thisfluid,calledlymph,returnstotheheartbywayofanothersystemofchannelsthelymphvessels.Lymphnodesalongthesevesselsfilterthefluidbeforeitreenterstheblood.Thespleenisalargelymphaticorganthatfilterstheblood.——结将淋巴液过滤，过滤后再回流人血液。脾是一个过滤血液的大淋巴器官。Therespiratorysystemtakesinoxygenfrom theairandexpelscarbondioxideandwatervapor.Airentersthenoseandmouthandtravelsthroughthelarynx,andtrachea.Thetracheadividestoentereachofthetwolungsandthendividesmorethan20timestoformaverylargenumberofsmallairspaces.Oxygenfromtheairentersthebloodthroughcapillariesinthewallsoftheseairspaces,andthebloodreleasecarbondioxideintotheairspacestobeexhaled. 系统从空气中摄取氧气，并将二氧化碳、水蒸气排出体外。空气经鼻腔、口腔人喉管、气20小的肺泡。从空气摄取的氧气流经这些肺泡壁内的毛细血管流入血液，血液再经肺泡把释放出的二氧化碳排出体外。Thedigestivesystemconsistsofatubeextendingfromthemouthtotheanus.Init,foodandfluidsaretakenin,movedthroughthebody,andbrokendownintosmallmoleculesthatareabsorbedintothecirculatorysystem.Thisbreakdown,knownasdigestion,isbothamechanicalandachemicalprocess.个机械过程，也是一个化学过程。Foodentersthroughthemouth,wherechewingandsalivastarttobreakitupandmakeiteasiertoswallow.Next,thefoodtravelsdownthroughtheesophagustothestomach.Contractionsofthestomach'smuscularwallcontinuetobreakdownthefoodmechanically,andchemicaldigestioncontinueswhenacidandenzymesaresecretedintothestomachcavity.食物壁的收缩继续机械化地分解食物，而当酸和酶分泌入胃腔时，化学性消化开始。Theliquifiedfoodgraduallypassesintothesmallintestine.Inthefirstpartofthesmallintestine,calledtheduodenum,enzymesfromthepancreasareadded.Theseenzymescompletethechemicalbreakdownofthefood.Thedigestionoffatisaidedbybile,whichismadeintheliverandstoredinthegallbladder.Thesmallintestineofanadultisabout21feet(6.4meters)long.Mostofitslengthisdevotedtoabsorbingthenutrientsreleasedduringthesedigestiveactivities.液体化食物逐渐进入小肠。小肠的起始部分叫十二指肠，胰腺分泌的酶辅助食物消化。这些酶完成食物的化学分解。肝脏分泌的胆汁贮存在胆囊内21英尺（6.4米）长。小肠的大部分肠段用来吸收消化过程中释放的营养物质。Theliquidremainderofthefoodentersthelargeintestine,orcolon,whichisabout12feet(3.7meters)long.Itismorethantwiceaswideasthesmallintestine.Inthelargeintestinemostofthefluidisabsorbed,andtherelativelydryresiduesareexpelled.液状的剩余食物进入大肠，12英尺（3.7米）吸收，相对干化的残余物被排出体外。Theurinarysystemmaintainsnormallevelsofwaterandofcertainsmallmoleculessuchassodiumandpotassiuminthebody.Itdoesthisbypassingbloodthroughthekidneys,twoefficientfilteringorgansthatgetridofanyexcessofvariousmoleculesandconservethosemoleculesthatareinshortsupply.泌尿系统维持水分及体内某些小分子物质，如钠、钾的正种多余的小分子物质，保留那些供应不足的小分子物质。Thefluidthatleavesthekidneys,knownasurine,travelsthroughatubecalledtheuretertothebladder.Thebladderholdstheurineuntilitisvoidedfromthebodythroughanothertube,theurethra.胱另一端的管道排出。Theendocrinesystem.Thetwosystemsthatcontrolbodyactivitiesaretheendocrinesystemandthenervoussystem.Theformerexertsitscontrolbymeansofchemicalmessengerscalledhormones.Hormonesareproducedbyavarietyofendocrineglands,whichreleasethehormonesdirectlyintothebloodstream.——Amajorglandisthepituitary,whichislocatedunderthebraininthemiddleofthehead.Itproducesatleasteighthormones,whichaffectgrowth,kidneyfunction,anddevelopmentofthesexorgans.Becausesomeofthepituitary'shormonesstimulateotherglandstoproducetheirownhormones,thepituitarycalledthemastergland. 方。它至少分泌八种激素，这些激素对人体生长、肝功能及性器官发育有影响。因为脑垂体分泌的一些激素促进其他腺体分泌激素，所以脑垂体是主要腺体。Anothergland,thethyroid,islocatedbetweenthecollarbones.Itshormonecontrolstherateofthebody'smetabolism.Thesexorgans(ovariesendtestes)makethesexcellsandalsomakehormonesthatcontrolcertaincharacteristicsofmalesandfemales.Locatedontopofeachkidneyistheadrenalgland,whichproducescortisoneandadrenaline.Thepancreasproducesnotonlydigestiveenzymesbutalso3insulinandglucagon,whichcontrolthebody'suseofsugarandstarches.另一个腺体，甲状腺，位于锁骨之间。甲状腺激素调控着机体新陈代谢的速度。性器官（卵巢、睾丸）分泌性细胞和性激素，这些激素控制着男性和女性的某些特征。每边肾上方是肾上腺，它分泌可的松和肾上腺激素。胰腺不仅分泌消化酶，而且分泌胰岛素和高血糖素，这两种激素控制机体的糖分及淀粉的消耗。Thenervoussystem.Thebrain,thespinalcordandthenerve-alsocontrolsbodyactivities.Thelowerpartsofthebraincontrolbasicfunctionssuchasbreathingandheartrateaswellasbodytemperature,hunger,andthirst.Abovetheseregionsarethecentersforsight,sound,touch,smell,andtaste,andtheregionsthatdirectvoluntary muscularactivitiesofthearmsandlegs.Performedherearethehigherfunctionsofintegratingandprocessinginformation.脑、脊髓及神经，也调控机体活动。脑的偏下部位控制着诸如呼吸、心跳、体温、饥渴的基本活动。而脑的偏上部位则是视觉、听觉、触觉、嗅觉及味觉中心，也是指挥臂、腿随意肌肉运动的区域。神经系统更高级的功能是整合、处理信息。Thebrainreceivesandsendsinformationbymeansofnerves,manyofwhichliepartlyinthespinalcord.Thespinalcordisprotectedbythespinalcolumn.Nervesenterandleavethespinalcordateachlevelofthebody,travelingtoandfromthearms,legs,andtrunk.Thesenervesbringinformationfromthevarioussenseorgans.Theinformationisprocessedbythebrain,andthenmessagesarecarriedbacktomusclesandglandsthroughoutthebody.脑通过神经脑处理后输送回全身及腺体Thereproductivesystemisconstructeddifferentlyformalesandfemales.Themalereproductivesystemisresponsibleforproducing,transportingandmaintainingviablesperm(themalesexcell).Italsoproducesthemalesexhormone,testosterone,whichregulatesthedevelopmentofabeard,pubichair,adeepvoiceandotherbodilycharacteristicsoftheadultmale.男、女性的生殖系统不同。男性生殖系统产生、输送、维持能存活的精子（男性性细胞育的特征。Thefemaleproductivesystemisresponsibleforproducingandtransportingova(thefemalesexcells),eliminatingovafromthebodywhentheyarenotfertilizedbysperm,nourishingandprovidingaplaceforgrowthofanembryowhenanovumisfertilizedbysperm,andnourishinganewbornchild.Thefemalereproductivesystemalsoproducesthefemalesexhormones,estrogenandprogesterone,whichregulatethedevelopmentofbreastsandotherbodilycharacteristicsofthematurefemale.（女性性细胞而当精、卵结合时，女性生殖系统培养、提供胚胎生长场所，并孕育新生儿。女性生殖系——雌激素和孕酮，以此调节乳房及其他成熟女性身体发育的特征。Theskinisacompletelayerthatprotectstheinnerstructuresofthebody,anditisthelargestofthebody'sorgans.Itkeepsoutforeignsubstancesandpreventsexcessivewaterevaporation.Thenervesintheskinprovidetactileinformation.Theskinalsohelpskeepthebody'stemperaturecloseto37C,heatisconservedbyreducingbloodflowthroughtheskinorisexpendedbyincreasingbloodflowandbyevaporationofsweatfromtheskin.Hairandnailsareaccessorystructuresoftheskin.皮肤防御外来侵袭，防止过多水分蒸发。皮肤上的神经提供触觉信息。皮肤也能将体温维98.6华氏度（37摄氏度肤的血流增加及汗液蒸发时，热量就散发。头发及指甲是皮肤的附属结构。CellsandTissues细胞与组织Inthispassage,youwilllearn:1.Humanbodysystemsasawhole2.Vitalpartsofacell3.FourkindsoftissuesCellsareorganizedintotissues,andtissuesarearrangedintoorgans,whichinturnaregroupedintosystems.Eachbodysystemservesitsspecificfunctions.Bearinmindhoweverthatthebodyfunctionsasawholenosystemisindependentoftheothers.Theyworktogethertomaintainthebody’sstateofinternalstabilityhomeostasis.Nowlet’sbeginourdiscussionwithcells,thesmallestunitoflivingmatterthatcanexistbyitself.细胞构成组织，组织构成器机体是作用保持了机体内部的稳定状态，即体内平衡。现在，我们先讨论细胞─能独立存在活性物质的最小单位。Thebodycanbestudiedfromitssimplesttoitsmostcomplexlevel,beginningwiththecell.Allbodyfunctionsresultfromtheactivitiesofbillionsofthespecializedcells.Someplantsandanimalsconsistofonlyasinglecell.Othersarecomposedofmanybillionsofcells. 从细胞开胞活动，有的动植物仅由一个细胞构成，其他生物则由亿万个细胞构成。Cellsexistinavarietyofshapesandsizes.Theymay,forexample,becube-shapedorflat.Scientistswhostudycellshavedeterminedthatasinglecellmaybeaslargeasatennisballorsosmallthatthousandswouldfitonthepointofaneedle.Theyolkofahen’seggisactuallyaverylargecell.Bycontrast,bacteriaeachoneofwhichisatinycell areamongthesmallestRegardlessofitsshapeorsize,everycellcontainsthe“machinery”neededtomaintainlife.Whilenormallycellsfunctionwithgreatefficiency,theyaresubjecttovariousdisordersthatresultindisease.究发现单独一个细胞可以像网球一样的大小，或小到几千个细胞才能刚好填满针头。鸡的蛋黄是一个非常大的单细胞。微小的细菌呢算是最小的细胞。不管是细胞大小或形状的不同，每个细胞都有“需要存活的机制”。对每个正常的细胞，有效力的细胞，都存在许多问题，能导致疾病。Thesizeofcellsisusuallymeasuredinmicrons.Amicronisamillionthofameter,andabout25,000micronsequaloneinch.Thesmallestbacteriaareabout0.2micronindiameter.Theaveragecellinthehumanbodyabouttenmicronsindiameterisaspeckbarelyvisiblewithouttheaidofamicroscope.微米微米等于一寸。最小的细菌的圆径是0.2微米，肉眼勉强可以看得到，不需要显微镜的帮助。Thestudyofcellsisthebranchofbiologycalledcytology.Thesciencethatdealswithcellsonthesmalleststructuralandfunctionalleveliscalledmolecularbiology.研究关于“”是生学。Allcellsconsistofprotoplasm,the“livingjelly.”Theprotoplasmofatypicalcellformsthreevitalparts thecellmembrane,thecytoplasm,andthenucleus.Themembraneenclosestheothercellstructures.Muchofthechemicalworkofthecellisdoneinthecytoplasm,whichsurroundsthenucleus.Thenucleus,enclosedbyitsownmembrane,isthecontrolcenterofthecell.(seeFigure1-1)““心。thecellsMembrane细胞膜Cellscansurviveonlyinaliquidmediumthatbringsinfoodandcarriesawaywaste.Forone-celledorganismsthisfluidisanexternalbodyofwater theocean,alake,orastream.many-celledplantsandanimals,however,themediumispartoftheorganism inplants,thesap;inanimals,theblood.来说，这就是细胞外的液体，如：大海里、河里或水流中。在对多细胞生物而言，这种媒介就是生物体的一部分，植物以汁液的形式，动物以血液的形式。Thecellmembraneissemipermeable,ordifferentiallypermeablesomesubstancescanpassthroughit,butotherscannot.Thischaracteristicenablesthecelltoadmitusefulsubstancesandtorejectharmfulsubstancesfromthesurroundingfluidaswellasto forceout,orexcretewasteproductsintothefluid.个特殊性使细胞对细胞周围只吸收了需要的物质而排除掉有害的物质，包括细胞内的废物通过液体化后排出细胞外。Thecellmembraneisanextremelythinbuttoughbandofproteinandphospholipidmolecules.Phospholipidsarechemicalssimilartostoredfat.Ontheevidenceofelectronmicrographs,biologistsbelievethatithasporesthroughwhichcertainsmallmoleculespassintact.Substancesprobablypassthroughthecellmembraneinseveralways.Smallchamberslocatedonthecellmembranecalledcaveolaegatherchemicalsignalsandchannelthemintothecells.Thecaveolaemayalsohelpdistributeproteinsthroughoutthecell.Largemoleculesenterthecellbyaprocesscalleddiffusion,inwhichtheymaybedissolvedbysubstancesinthecellmembrane.Theycanthenthroughthemembranewithoutdifficulty.Somecellstakeinlargemoleculesbymeansofpinocytosis.Inthisprocess,thecellmembraneformsapocketaroundlargemoleculesfloatingagainstit.Themolecule-and-fluid-filledpocketthenbreadsloosefromthemembranetobecomeabubblelikevacuole,andthevacuolethendriftsintothecytoplasm.Finally,thevacuolewallbreaksupandthemoleculesarereleasedintothecytoplasm.细胞膜是一种非常薄但确以很坚固的蛋白磷脂膜形成。磷脂是一种类似于储存的脂肪的蛋白物质。通过电子显微镜，生物学家相信细胞膜有孔，使较小的物质完全可以通过。物质可通过多种方式从细胞膜进入。细胞膜上的结构，称“小穴”，可接受化学信号再传到细胞内。小穴还可能参于细胞蛋白的分配。大的分子可通过“渗滤”进入细胞内，或被细胞膜内体分解，使它们更容易的进入细胞内。有些细胞可通过“胞饮”方式吞饮较大的物质。这个过程是通过细胞膜在大物质形成了“带”把它包围着，将它以泡状的“液泡”引入细胞质，最后包围解散，大物质成功的进入细胞内。Thecytoplasm细胞质Thecytoplasmismainlywater.Itswatercontentvariesfromaminimumofabout65percenttoamaximumofabout95percent.Thesolidsinthecytoplasmincludegranularproteins,carbohydrates,dropletsoffat,andpigments.Thecytoplasmisthusacolloidalsystem.细胞质主水”6595碳水化合物、脂肪小滴和色素。细胞质是胶体性的。Thecytoplasmmaybeeitherwateryorsyrupy,dependingontheconcentrationofsolidsdispersedinthefluid.Whenthesolidcontentdecreases,thesestructuresseemtovanish.Changesinconcentrationalsoproduceanapparentsteamingofthecytoplasmfromplacetoplacewithinthecell.Thisoccurs,forexample,whenfoodmoleculesenterthecell.细胞质可能是水性或糖浆性，根据散在细胞质内固体的浓度。当固体成分浓度增多，膜状和纤维状结果在细胞质显出。而当固体成分浓度减少时，膜状和纤维状的结构就消失。浓度的变化还可以表现细胞质内局部流动的变化。食物分子进入时可见。Mostofthecell’sconstantworkofkeepingaliveisperformedinthecytoplasm.Herefoodmoleculesarechangedintothematerialneededforenergyandmaterialsforgrowthorstiffeningofthecellmembranearemanufacturesneededbytherestoftheorganism.Forexample,plantcellscontainingchlorophyllmanufactureglucoseaplantfoodfromcarbondioxideandwater.大部分为了细胞存活的工作都在此处（细胞质）完成的。在此处，食物物质将被转物的食物，从水和二氧化碳合成。Oneofthecytoplasm’skeyenergytransactionsoccursinthesausage-shapedmitochondria.Eachmitochondrionhasaninnerandanoutermembrane.Likethecellmembrane,themembranesofthemitochondrionaresemipermeable.Foodmoleculesthatpassintothecytoplasmaretakenintothemitochondriaandoxidized,orburned,forenergy.细胞质能量转换也是半渗透性。进入线粒体的食物分子被氧化提供出能量。Theendoplasmicreticulum,anetworkofmembranoustubes,runsthroughthecytoplasm.Intheopinionofsomebiologists,thisnetworkisacontinuousstructurethatbeginsatthecellmembrane,twiststhroughthecytoplasm,andendsatthemembranesurroundingthenucleus.Locatedalongtheendoplasmicreticulumaswellaselsewhereinthecytoplasmarenumerousribosomes.Thesetinygranulesconsistinpartofribonucleicacid(RNA).Proteinsaremanufacturedattheribosomes.TheGolgicomplex,orGolgiapparatus,isamembranousstructurecomposedofstacksofthinsacs.NewlymadeproteinsmovefromtheendoplasmicreticulumtotheGolgicomplex,wheretheyarestoredforlatersecretion.胞浆网，在细胞质中成的蛋白从胞浆网移动到高尔基体储存，为了后来分泌所用。Vacuolesdriftthroughthecytoplasmandusuallycarryfoodmoleculesinsolution.Lysosomesarestructuressomewhatsimilarinappearancetovacuolesbutdenser.Theyappeartohaveadigestivefunction.Eachlysosomeisfilledwithdigestiveenzymesandencasedinamembrane.Lysosomesarebelievedtobreakdownfoodsubstancesbroughtintothecellbypinocytosis.IthasbeensuggestedthattheGolgicomplexplaysapartintheformationoflysosomes.在细胞质内游动的液泡一般是带着食物分子的溶液。溶酶体是一种有点像液泡胞饮方式的大物质。也认为高尔基体对溶酶体的形成有关系。TheNucleus细胞核Nearthecenterofthecellisaroundishoroval-shapednucleus.Thenucleuscontrolsthegrowthanddivisionofthecell.Italsocontainsthestructuresthattransmithereditarytraits.细胞Enclosedbyatwo-layeredmembrane,thenucleuscontainsaliquidcallednucleoplasmaswellasstrandsofdeoxyribonucleicacid(DNA)coveredwithacoatingofprotein.AstrandofDNAconsistsofalongseriesofgenes,whicharetheunitsofheredityofplantsandanimals.Genesdeterminethecharacteristicsofacell.TheydothisbyregulatingtheproductionofRNA,whichinturncontrolsthemanufactureofspecificproteins.为“核质（浆）”的液体和脱氧核糖核酸的蛋白层。脱氧核糖核酸缕是很长的基因系列所组成的，它是植物和动物的遗传信息。基因决定了细胞的特征。它是通过调节核糖核酸，使核糖核酸产出特异的蛋白。Humancells,forexample,makeonlyproteinsuniquetohumanbeingsDNAstrandsareusuallytoothinlystrungouttobeseenwithanopticalmicroscope.Becausethestrandsarereadilystainedwithdyes,theyarecalledchromatin.Whenacellbeginstodivide,however,thechromatinthickensintotheformofchromosomes.白。脱氧核糖核酸缕一般都很细小过光学显微镜能观察到。因为脱氧核糖核酸缕能够染色“染色质”。Anucleusnotundergoingdivisionhasatleastonenucleolus.ThenucleoluscontainsaconcentrationofRNA.BiologiststhinkRNAismadeinitiallyinthenucleusaccordingtoaDNA“blueprintandstoredthereuntilneededforproteinmanufacture.细胞核分化核仁不会减少，据脱氧核糖核酸的蓝图造出而藏在此处直到有蛋白合成的需要。thenucleusofanimalcellsisasphericalstructurecalledthecentrosome,fromwhichastersradiate.Thecentrosomecontainsapairofroddedstructurecalledcentrioles,whichusuallylieatrightanglestoeachother.Althoughcentriolesandcentrosomeshavenotbeenseeninplantcells,biologistsbelievethatplantcellscontainsimilarstructures.靠近动物的细胞核的圆形结构叫“中心体”，可见呈放射状散发的星体。中心体内含有一对棍状结构，称为“中心粒”，一般都形成正确固定的角度。无法在植物细胞发现中心体和中心粒，但生物学家认为植物应该有存在类似功能的其他结构。Tissues组织Cellsareorganizedintotissuesthatperformspecificfunctions.Thefourbasictissuetypesareasfollows:多细胞组成了组织，为了特异的功能。四种基本的组织：Epithelialtissuescoversandprotectsbodystructuresandlinesorgans,vessels,cavities.:覆盖及保护着身体结构和分清器官、导管和空腔。Connectivetissuessupportsandbindsbodystructures.Itcontainsfibersandothernonlivingmaterialbetweenthecells;includedarefattissues,cartilage,boneandblood.结缔组织:骨、骨头和血液。Muscletissuescontractstoproducemovement.Thethreetypesare：skeletalorvoluntarymusclethatmovestheskeleton;thecardiacmuscleoftheheart;andthesmoothmusclethatformsthewallsoftheabdominalorgans.Cardiacandsmoothmusclecanfunctionwithoutconsciouscontrolandarethusdescribedasinvoluntarymuscle.:通过收拾来产生道壁的肌肉。心机和平滑肌是非意识性，不随意性肌肉。Nervoustissue——makesupthebrain,spinalcord,andnerves.Itcoordinatesandcontrolsbodyresponsesbytransmittingelectricalimpulses.神经组织:通过动作电位来超空身体。Thesimplesttissuesaremembranes.Mucousmembranessecretethickfluidcalledmucusthatprotectsunderlyingtissues.Serousmembranessecreteathin,wateryfluid.Theylinebodycavitiesandcoverorgans.作用。粘液组织分泌出较稀的粘液，起得身体导管的分界和覆盖着各个器官。HumandiseasesInthispassageyouwilllearn:1.diseaseandpathology2.theclassificationofdiseases3.germs’invasionofthehumanbody4.thebody’sdefenseagainstinvasion5.thebody’simmunitytodiseasesThebriefsurveyofthehumanbodyinChapterOnehasgivenusaglimpseintotwodifferentstudiesthatareconsideredthefundamentalsofmedicalsciences,namelyanatomyandphysiology.However,thepictureisnotcompletewithoutconsideringpathology,thesciencethatdealswiththestructuralandfunctionalchangesproducedbythedisease.Infact,themodernapproachtothestudyofdisorderemphasizesthecloserelationshipofthepathologicalandphysiologicalaspectsandtheneedtounderstandthefundamentalsofeachintreatinganybodydiseases.理学与生理学基础的重要性。Thenwhatisadisease?Itmaybedefinedasaconditionthatimpairstheproperfunctionofthebodyorofoneofitsparts.Everylivingthing,bothplantsandanimals,cansuccumbtodisease.People,forexample,areofteninfectedbytinybacteria,butbacteria,inturn,canbeinfectedbyevenmoreminuteviruses.那么什么是疾病呢？它可能被定义为正常的功能或是部分功能遭受损害时的一种状态。每一种生物、植物和动物，都会受制于疾病。例如，人Hundredsofdifferentdiseasesexist.Eachhasitsownparticularsetofsymptomsandsigns,cluesthatenableaphysiciantodiagnosetheproblem.Asymptomissomethingapatientcandetect,suchasfever,bleeding,orpain.Asignissomethingadoctorcandetect,suchasaswollenbloodvesseloranenlargedinternalbodyorgan.许多种疾病存在于世。每一种都有其特定的症状、征兆和线索，医生能以此诊断疾病之所在。症状是病人自己就能觉察到的，比如，高烧、流血，或是疼痛。而征兆则是医生能够观察到的，比如，血管扩张或是体内器官肿大。Diseasescanbeclassifieddifferently.Forinstance,anepidemicdiseaseisonethatstrikesmanypersonsinacommunity.Whenitstrikesthesameregionyearafteryearitisanendemicdisease.Anacutediseasehasaquickonsetandrunsashortcourse.Anacuteheartattack,forexample,oftenhitswithoutwarningandcanbequicklyfatal.Achronicdiseasehasaslowonsetandrunsasometimesyears-longcourse.Thegradualonsetandlongcourseofrheumaticfevermakesitachronicailment.Betweentheacuteandchronic,anothertypeiscalledsubacute.疾病可以划分为不同的种类，例如，流行病是一种在某一社区内侵袭许多人的疾病。当它年复一年地袭击同一社区，就成了一种地方病。急性病发作快，但病程短，举个例子来说，急性心脏病发作常常没有前兆，而且会很快致命。慢性病发作则慢，但病程有时会长达几年之久。风湿热正是由于发病慢、病程长而成为一种慢性失调病（慢性病性之间的另一种类型，就被称为亚急性。Diseasescanalsobeclassifiedbytheircausativeagents.Forinstance,aninfectious,orcommunicable,diseaseistheonethatcanbepassedbetweenpersonssuchasbymeansofairbornedropletsfromacoughorsneeze.Tinyorganismssuchasbacteriaandfungicanproduceinfectiousdiseases.Socanviruses.Socantinyworms.Whateverthecausativeagentmightbe,itsurvivesinthepersonitinfectsandispassedontoanother.Sometimes,adisease-producingorganismgetsintoapersonwhoshowsnosymptomsofthedisease.Theasymptomaticcarriercanthenpassthediseaseontosomeoneelsewithoutevenknowinghehasit. 也不知情的情况下就把疾病传染给了他人。Noninfectiousdiseasesarecausedbymalfunctionsofthebody.Theseincludeorganortissuedegeneration,erraticcellgrowth,andfaultybloodformationandflow.Alsoincludedaredisturbancesofthestomachandintestine,theendocrinesystem,andtheurinaryandreproductivesystems.Somediseasescanbecausedbydietdeficiencies,lapsesinthebody'sdefensesystem,orapoorlyoperatingnervoussystem.非传染性疾病是由身体功能失调引起的组织退化、异常细胞生成，以及异常的血液生成和血液循环。当然其中也包括胃、肠、内分泌系统和泌尿生殖系统的紊乱。一些疾病也可能是由饮食不足、身体抵抗力下降、或是神经系统工作不造成的。Disabilityandillnessescanalsobeprovokedbypsychologicalandsocialfactors.Theseailmentsincludedrugaddiction,obesity,malnutrition,andpollution-causedhealthproblems.心造成的健康问题。Furthermore,athousandormoreinheritablebirthdefectsresultfromalternationsingenepatterns.Sincetinygenesareresponsibleforproducingthemanychemicalsneededbythebody,missingorimproperlyoperatinggenescanseriouslyimpairhealth.Geneticdisordersthataffectbodychemistryarecalledinbornerrorsofmetabolism.Someformsofmentalretardationarehereditary.而且，有上千种乃至为数更多的遗传性出生缺陷是由于基因变化而造成的。由育迟缓就是因遗传而造成的。HowGermsInvadetheBody病菌是怎样侵袭身体Humansliveinaworldwheremanyotherlivingthingscompeteforfoodandplacestobreed.Thepathogenicorganisms,orpathogens,oftenbroadlycalledgerms,thatcausemanydiseasesareabletoinvadethehumanbodyanduseitscellsandfluidsfortheirownneeds.Ordinarily,thebody'sdefensesystemcanwardofftheseinvaders.御系统能够阻止这些入侵者。Pathogenicorganismscanenterthebodyinvariousways.Somesuchasthesethatcausethecommoncold,pneumonia,andtuberculosisarebreathedin.Otherssuchasthosethatcausevenerealdiseasesenterthroughsexualcontactofhumanbodies.Stillotherssuchasthosethatcausehepatitis,colitis,cholera,andtyphoidfever-getinthebodythroughcontaminatedfood,waterorutensils.进入体内的，比如那些引起肝炎、霍乱和伤寒热的病原体。Insectscanspreaddiseasebyactingasvectors,orcarriers.Fliescancarrygermsfromhumanwasteorothertaintedmaterialstofoodandbeverages.Germsmayalsoenterthebodythroughthebiteofamosquito,louse,orotherinsectvector.蚊子、虱子或其它媒介动物的叮咬，病菌也可能进入体内。HowtheBodyFightsDisease身体是怎样抵抗疾病的Asafirstlineofdefense,ahealthybodyhasanumberofphysicalbarriersagainstinfection.Theskinandmucousmembranescoveringthebodyorliningitsopeningsofferconsiderableresistancetoinvasionbybacteriaandotherinfectiousorganisms. Ifthesephysicalbarriersareinjuredorburned,infectionresistancedrops.Inminorcases,onlyboilsorpimplesmaydevelop.Inmajorcases,however,largeareasofthebodymightbecomeinfected.健康的身体有许多屏障来抵御感染的发生。覆盖在体表或者器官开口处的皮肤和粘膜能在很大程度上抵抗细菌或其它感染体的入侵。如果这些屏障遭到了损坏或烧伤，身体对感染的抵抗力就会下降。在一些病情较轻的病例中，疥子和小脓胞可能会发生。在病情较重的病例中，身体的大面积区域则可能会被感染。Breathingpassagesareespeciallyvulnerabletoinfection.Fortunately,theyarelinedwithmucus-secretingcellsthattraptinyorganismsanddustparticles.Also,minutehairscalledcilialinethebreathingpassages,wavelikeafieldofwheat,andgentlysweepmatteroutoftherespiratorytract.Inaddition,foreignmatterinthebreathingpassagescanoftenbeejectedbynoseblowing,coughing,sneezing,andthroatclearing.Unfortunately,repeatedinfection,smokingandothercausescandamagetherespiratorypassagewaysandmakethemmoresusceptibletoinfection.抽烟或其它别的原因会损坏呼吸道，并且使它们容易受到感染。Manypotentialinvaderscannotstandbodytemperature(98.6°For37°C).Eventhosethatthriveatthattemperaturemaybedestroyedwhenthebodyassumeshigher,fevertemperatures.98.637烧温度，甚至一些在先前温度下能蓬勃繁殖的病菌也可能会因此而遭到毁灭。Waxintheouterearcanalsandtearsfromeyeductscanslowthegrowthofsomebacteria.Andstomachacidcandestroycertainswallowedgerms.缓一些细菌的生长速度，而胃酸也能毁掉某种吞食进去的病菌。Thebody'ssecondlineofdefenseisinthebloodandlymph.Certainwhitebloodcellsflocktoinfectedareasandtrytolocalizetheinfectionbyformingpus-filledabscesses.Unlesstheabscessbreaksandallowsthepustodrain,theinfectionislikelytospread.Whenthishappens,theinfectionisfirstblockedbylocallymphglands.Forexample,aninfectioninthehandtravelsupthearm,producingredstreaksandswollen,tenderlymphglandsinthearmpit.Unlesstheinfectionisbroughtundercontrol,itwillresultinbloodpoisoning. 痛。如果不及时控制住感染的上传，将会导致血液中毒。Phagocytesarelocatedatvarioussitestominimizeinfection.Onetypeinthespleenandliverkeepsthebloodclean.Othersinsuchhigh-riskareasasthewallsofthebronchiandtheintestinesremovecertainbacteriaandshatteredcells.得感染的机会变小。位于肝脾内的一类能使身体的血液保持干净。其它的位于像支气管壁和肠壁这样高危险区的类型能清除某类细茵和已解体的细胞。HowWeBecomeImmunetoDisease我们是怎样变得对疾病有免疫力的Thebodyhasaspecialwayofhandlinginfection.Ithasasystemthatfendsoffthefirsttracesofaninfectioussubstanceandthen,througha"memory,"givesthebodyalong-lastingimmunityagainstfutureattacksbythesamekindofinvader.统，能够一开始就阻止感染性物质的侵袭，然后通过“记忆”，它能给身体—个长期的免疫力来抵抗将来由同种入侵者引起的侵袭。Manysubstancescouldharmthebodyiftheyeverenteredit.Thesesubstances,orantigens,rangefrombacteriaandpollentoatransplantedorgan(viewedbythebodyasaninvader).Tofightthemthebodymakesspecialchemicalsknownas体视