醫(yī)學(xué)專業(yè)英語(yǔ)翻譯及答案

PAGEPAGE34Inthispassageyouwilllearn:

Chapter1Passage1HumanBodyClassificationoforgansystems2.Structureandfunctionofeachorgansystem3.AssociatedmedicaltermsTounderstandthehumanbodyitisnecessarytounderstandhowitspartsareputtogetherandhowtheyfunction.Thestudyofthebody'sstructureiscalledanatomy;thestudyofthebody'sfunctionisknownasphysiology.Otherstudiesofhumanbodyincludebiology,cytology,embryology,histology,endocrinology,hematology,immunology,psychologyetc.了解人體各部分的組成及其功能，對(duì)于認(rèn)識(shí)人體是必需的。研究人體結(jié)構(gòu)的科學(xué)叫解剖學(xué)；研究人體功能的科學(xué)叫生理學(xué)。其他研究人體的科學(xué)包括生物學(xué)、細(xì)胞學(xué)、胚胎學(xué)、組織學(xué)、內(nèi)分泌學(xué)、血液學(xué)、遺傳學(xué)、免疫學(xué)、心理學(xué)等等。Anatomistsfinditusefultodividethehumanbodyintotensystems,thatis,theskeletalsystem,themuscularsystem,thecirculatorysystem,therespiratorysystem,thedigestivesystem,theurinarysystem,theendocrinesystem,thenervoussystem,thereproductivesystemandtheskin.Theprincipalpartsofeachofthesesystemsaredescribedinthisarticle.解剖學(xué)家發(fā)現(xiàn)把整個(gè)人體分成骨骼、肌肉、循環(huán)、呼吸、消化、泌尿、內(nèi)分泌、神經(jīng)、生殖系統(tǒng)以及感覺(jué)器官的做法是很有幫助的。本文描繪并闡述了各系統(tǒng)的主要部分。Theskeletalsystemismadeofbones,jointsbetweenbones,andcartilage.Itsfunctionistoprovidesupportandprotectionforthesofttissuesandtheorgansofthebodyandtoprovidepointsofattachmentforthemusclesthatmovethebody.Thereare206bonesinthehumanskeleton.Theyhavevariousshapes-long,short,cube-shaped,flat,andirregular.Manyofthelongboneshaveaninteriorspacethatisfilledwithbonemarrow,wherebloodcellsaremade.骨骼系統(tǒng)由骨、關(guān)節(jié)以及軟骨組成。它對(duì)軟組織及人體器官起到支持和保護(hù)作用，并206根骨頭。骨形態(tài)不一，有長(zhǎng)的、短、立方的、扁Ajointiswherebonesarejoinedtogether.Theconnectioncanbesoclosethatnomovementispossible,asisthecaseintheskull.Otherkindsofjointspermit movement:eitherbackandforthinoneplane-aswiththehingejointoftheelbow-ormovementaroundasingleaxis-aswiththepivotjointthatpermitstheheadtorotate.Awiderangeofmovementispossiblewhentheball-shapedendofonebonefitsintoasocketattheendofanotherbone,astheydointheshoulderandhipjoints.關(guān)節(jié)把骨與骨連接起來(lái)。顱骨不能運(yùn)動(dòng)，是由于骨與骨之間的連接太緊密。但其它的關(guān)節(jié)可允許活動(dòng)，如一個(gè)平面上的前后屈伸運(yùn)動(dòng)，如肘關(guān)節(jié)；或是繞軸心旋轉(zhuǎn)運(yùn)動(dòng)，如樞軸點(diǎn)允許頭部轉(zhuǎn)動(dòng)。如果一根骨的球形末端插入另一根骨的臼槽里，大輻度的運(yùn)動(dòng)（如肩關(guān)節(jié)、髖關(guān)節(jié)）即成為可能。Cartilageisamoreflexiblematerialthanbone.Itservesasaprotective,cushioninglayerwherebonescometogether.Italsoconnectstheribstothebreastboneandprovidesastructuralbaseforthenoseandtheexternalear.Aninfant'sskeletonismadeofcartilagethatisgraduallyreplacedbyboneastheinfantgrowsintoanadult.軟骨是一種比一般骨更具韌性的物質(zhì)。它是骨連結(jié)的保護(hù)、緩沖層。它把肋骨與胸骨連結(jié)起來(lái)，也是鼻腔與內(nèi)耳的結(jié)構(gòu)基礎(chǔ)。一個(gè)嬰兒的骨骼就是由軟骨組成，然后不斷生長(zhǎng)、骨化，使嬰兒長(zhǎng)大成人。Themuscularsystemallowsthebodytomove,anditscontractionsproduceheat,helpsmaintainaconstantbodytemperature.Striatedmusclescanbeconsciouslycontrolled.Theendsofthesemusclesareattachedtodifferentbonesbyconnectivetissuebandssothatwhenthemusclecontracts,onebonemovesinrelationtotheother.Thismakesitpossibletomovethewholebody,aswhenwalking,ortomovejustonepartofthebody,aswhenbendingafinger.Contractionsoftheheartandsmoothmusclesarenotunderconsciouscontrol.Smoothmusclesarefoundinthewallsoforganssuchasthestomachandtheintestinesandservetomovethecontentsoftheseorgansthroughthebody.肌肉系統(tǒng)使軀體運(yùn)動(dòng)，肌肉收縮產(chǎn)生的熱有助于維持一個(gè)恒定的體溫。人體能夠有意識(shí)地控制條紋肌。結(jié)締組織使肌肉末端附著于不同的骨面上，所以當(dāng)肌肉收縮時(shí)，兩骨彼此靠近而產(chǎn)生運(yùn)動(dòng)。這也就使整個(gè)人體可以運(yùn)動(dòng)起來(lái)，器官壁內(nèi)層的平滑肌，如胃腸壁的平滑肌把胃腸中的物質(zhì)運(yùn)送到全身。Thecirculatorysystem.Allpartsofthebodymusthavenourishmentandoxygeninordertofunctionandgrow,andtheirwasteproductsmustberemovedbeforetheyaccumulateandpoisonthebody.Thecirculatorysystemdistributesneededmaterialsandremovesunneededones.Itismadeupoftheheart,bloodvessels,andblood,whichtogethermakeupthecardiovascularsystem.Thebloodisalsopartofthebody'sdefensesystem. Ithasantibodiesandwhitebloodcellsthatprotectthebodyagainstforeigninvaders.和氧氣來(lái)使之發(fā)揮功能和生長(zhǎng)，也需要在這些器官所產(chǎn)生的廢物積聚而危害生命之前將其排除。循環(huán)系統(tǒng)運(yùn)送有用物質(zhì)，排泄廢物。心血管系統(tǒng)是循環(huán)系統(tǒng)的組成之一；心血管系統(tǒng)包括心臟、血管及血液。血液也是機(jī)體防御系統(tǒng)的一個(gè)部分，血液中有抗體及白細(xì)胞來(lái)防止機(jī)體受到外來(lái)的侵襲。Theheartisamusclethatisdividedintotwonearlyidenticalhalves:onehalfreceivesbloodfromthelungsandsendsittotherestofthebody,theotherhalfsendsbloodthathastraveledthroughthebodybacktothelungs.Whentheheartmusclecontracts,thebloodisforcedoutintoarteriesandenterssmallcapillaries.Bloodreturnstotheheartthroughveins. 心臟是一塊被分送血液返回心臟。Alsofunctioningincirculationisthelymphaticsystem.Someofthefluidthatsurroundscellsdoesnotreenterthebloodvesselsdirectly.Thisfluid,calledlymph,returnstotheheartbywayofanothersystemofchannelsthelymphvessels.Lymphnodesalongthesevesselsfilterthefluidbeforeitreenterstheblood.Thespleenisalargelymphaticorganthatfilterstheblood.——結(jié)將淋巴液過(guò)濾，過(guò)濾后再回流人血液。脾是一個(gè)過(guò)濾血液的大淋巴器官。Therespiratorysystemtakesinoxygenfrom theairandexpelscarbondioxideandwatervapor.Airentersthenoseandmouthandtravelsthroughthelarynx,andtrachea.Thetracheadividestoentereachofthetwolungsandthendividesmorethan20timestoformaverylargenumberofsmallairspaces.Oxygenfromtheairentersthebloodthroughcapillariesinthewallsoftheseairspaces,andthebloodreleasecarbondioxideintotheairspacestobeexhaled. 系統(tǒng)從空氣中攝取氧氣，并將二氧化碳、水蒸氣排出體外?？諝饨?jīng)鼻腔、口腔人喉管、氣20小的肺泡。從空氣攝取的氧氣流經(jīng)這些肺泡壁內(nèi)的毛細(xì)血管流入血液，血液再經(jīng)肺泡把釋放出的二氧化碳排出體外。Thedigestivesystemconsistsofatubeextendingfromthemouthtotheanus.Init,foodandfluidsaretakenin,movedthroughthebody,andbrokendownintosmallmoleculesthatareabsorbedintothecirculatorysystem.Thisbreakdown,knownasdigestion,isbothamechanicalandachemicalprocess.個(gè)機(jī)械過(guò)程，也是一個(gè)化學(xué)過(guò)程。Foodentersthroughthemouth,wherechewingandsalivastarttobreakitupandmakeiteasiertoswallow.Next,thefoodtravelsdownthroughtheesophagustothestomach.Contractionsofthestomach'smuscularwallcontinuetobreakdownthefoodmechanically,andchemicaldigestioncontinueswhenacidandenzymesaresecretedintothestomachcavity.食物壁的收縮繼續(xù)機(jī)械化地分解食物，而當(dāng)酸和酶分泌入胃腔時(shí)，化學(xué)性消化開(kāi)始。Theliquifiedfoodgraduallypassesintothesmallintestine.Inthefirstpartofthesmallintestine,calledtheduodenum,enzymesfromthepancreasareadded.Theseenzymescompletethechemicalbreakdownofthefood.Thedigestionoffatisaidedbybile,whichismadeintheliverandstoredinthegallbladder.Thesmallintestineofanadultisabout21feet(6.4meters)long.Mostofitslengthisdevotedtoabsorbingthenutrientsreleasedduringthesedigestiveactivities.液體化食物逐漸進(jìn)入小腸。小腸的起始部分叫十二指腸，胰腺分泌的酶輔助食物消化。這些酶完成食物的化學(xué)分解。肝臟分泌的膽汁貯存在膽囊內(nèi)21英尺（6.4米）長(zhǎng)。小腸的大部分腸段用來(lái)吸收消化過(guò)程中釋放的營(yíng)養(yǎng)物質(zhì)。Theliquidremainderofthefoodentersthelargeintestine,orcolon,whichisabout12feet(3.7meters)long.Itismorethantwiceaswideasthesmallintestine.Inthelargeintestinemostofthefluidisabsorbed,andtherelativelydryresiduesareexpelled.液狀的剩余食物進(jìn)入大腸，12英尺（3.7米）吸收，相對(duì)干化的殘余物被排出體外。Theurinarysystemmaintainsnormallevelsofwaterandofcertainsmallmoleculessuchassodiumandpotassiuminthebody.Itdoesthisbypassingbloodthroughthekidneys,twoefficientfilteringorgansthatgetridofanyexcessofvariousmoleculesandconservethosemoleculesthatareinshortsupply.泌尿系統(tǒng)維持水分及體內(nèi)某些小分子物質(zhì)，如鈉、鉀的正種多余的小分子物質(zhì)，保留那些供應(yīng)不足的小分子物質(zhì)。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。它至少分泌八種激素，這些激素對(duì)人體生長(zhǎng)、肝功能及性器官發(fā)育有影響。因?yàn)槟X垂體分泌的一些激素促進(jìn)其他腺體分泌激素，所以腦垂體是主要腺體。Anothergland,thethyroid,islocatedbetweenthecollarbones.Itshormonecontrolstherateofthebody'smetabolism.Thesexorgans(ovariesendtestes)makethesexcellsandalsomakehormonesthatcontrolcertaincharacteristicsofmalesandfemales.Locatedontopofeachkidneyistheadrenalgland,whichproducescortisoneandadrenaline.Thepancreasproducesnotonlydigestiveenzymesbutalso3insulinandglucagon,whichcontrolthebody'suseofsugarandstarches.另一個(gè)腺體，甲狀腺，位于鎖骨之間。甲狀腺激素調(diào)控著機(jī)體新陳代謝的速度。性器官（卵巢、睪丸）分泌性細(xì)胞和性激素，這些激素控制著男性和女性的某些特征。每邊腎上方是腎上腺，它分泌可的松和腎上腺激素。胰腺不僅分泌消化酶，而且分泌胰島素和高血糖素，這兩種激素控制機(jī)體的糖分及淀粉的消耗。Thenervoussystem.Thebrain,thespinalcordandthenerve-alsocontrolsbodyactivities.Thelowerpartsofthebraincontrolbasicfunctionssuchasbreathingandheartrateaswellasbodytemperature,hunger,andthirst.Abovetheseregionsarethecentersforsight,sound,touch,smell,andtaste,andtheregionsthatdirectvoluntary muscularactivitiesofthearmsandlegs.Performedherearethehigherfunctionsofintegratingandprocessinginformation.腦、脊髓及神經(jīng)，也調(diào)控機(jī)體活動(dòng)。腦的偏下部位控制著諸如呼吸、心跳、體溫、饑渴的基本活動(dòng)。而腦的偏上部位則是視覺(jué)、聽(tīng)覺(jué)、觸覺(jué)、嗅覺(jué)及味覺(jué)中心，也是指揮臂、腿隨意肌肉運(yùn)動(dòng)的區(qū)域。神經(jīng)系統(tǒng)更高級(jí)的功能是整合、處理信息。Thebrainreceivesandsendsinformationbymeansofnerves,manyofwhichliepartlyinthespinalcord.Thespinalcordisprotectedbythespinalcolumn.Nervesenterandleavethespinalcordateachlevelofthebody,travelingtoandfromthearms,legs,andtrunk.Thesenervesbringinformationfromthevarioussenseorgans.Theinformationisprocessedbythebrain,andthenmessagesarecarriedbacktomusclesandglandsthroughoutthebody.腦通過(guò)神經(jīng)腦處理后輸送回全身及腺體Thereproductivesystemisconstructeddifferentlyformalesandfemales.Themalereproductivesystemisresponsibleforproducing,transportingandmaintainingviablesperm(themalesexcell).Italsoproducesthemalesexhormone,testosterone,whichregulatesthedevelopmentofabeard,pubichair,adeepvoiceandotherbodilycharacteristicsoftheadultmale.男、女性的生殖系統(tǒng)不同。男性生殖系統(tǒng)產(chǎn)生、輸送、維持能存活的精子（男性性細(xì)胞育的特征。Thefemaleproductivesystemisresponsibleforproducingandtransportingova(thefemalesexcells),eliminatingovafromthebodywhentheyarenotfertilizedbysperm,nourishingandprovidingaplaceforgrowthofanembryowhenanovumisfertilizedbysperm,andnourishinganewbornchild.Thefemalereproductivesystemalsoproducesthefemalesexhormones,estrogenandprogesterone,whichregulatethedevelopmentofbreastsandotherbodilycharacteristicsofthematurefemale.（女性性細(xì)胞而當(dāng)精、卵結(jié)合時(shí)，女性生殖系統(tǒng)培養(yǎng)、提供胚胎生長(zhǎng)場(chǎng)所，并孕育新生兒。女性生殖系——雌激素和孕酮，以此調(diào)節(jié)乳房及其他成熟女性身體發(fā)育的特征。Theskinisacompletelayerthatprotectstheinnerstructuresofthebody,anditisthelargestofthebody'sorgans.Itkeepsoutforeignsubstancesandpreventsexcessivewaterevaporation.Thenervesintheskinprovidetactileinformation.Theskinalsohelpskeepthebody'stemperaturecloseto37C,heatisconservedbyreducingbloodflowthroughtheskinorisexpendedbyincreasingbloodflowandbyevaporationofsweatfromtheskin.Hairandnailsareaccessorystructuresoftheskin.皮膚防御外來(lái)侵襲，防止過(guò)多水分蒸發(fā)。皮膚上的神經(jīng)提供觸覺(jué)信息。皮膚也能將體溫維98.6華氏度（37攝氏度膚的血流增加及汗液蒸發(fā)時(shí)，熱量就散發(fā)。頭發(fā)及指甲是皮膚的附屬結(jié)構(gòu)。CellsandTissues細(xì)胞與組織Inthispassage,youwilllearn:1.Humanbodysystemsasawhole2.Vitalpartsofacell3.FourkindsoftissuesCellsareorganizedintotissues,andtissuesarearrangedintoorgans,whichinturnaregroupedintosystems.Eachbodysystemservesitsspecificfunctions.Bearinmindhoweverthatthebodyfunctionsasawholenosystemisindependentoftheothers.Theyworktogethertomaintainthebody’sstateofinternalstabilityhomeostasis.Nowlet’sbeginourdiscussionwithcells,thesmallestunitoflivingmatterthatcanexistbyitself.細(xì)胞構(gòu)成組織，組織構(gòu)成器機(jī)體是作用保持了機(jī)體內(nèi)部的穩(wěn)定狀態(tài)，即體內(nèi)平衡?，F(xiàn)在，我們先討論細(xì)胞─能獨(dú)立存在活性物質(zhì)的最小單位。Thebodycanbestudiedfromitssimplesttoitsmostcomplexlevel,beginningwiththecell.Allbodyfunctionsresultfromtheactivitiesofbillionsofthespecializedcells.Someplantsandanimalsconsistofonlyasinglecell.Othersarecomposedofmanybillionsofcells. 從細(xì)胞開(kāi)胞活動(dòng)，有的動(dòng)植物僅由一個(gè)細(xì)胞構(gòu)成，其他生物則由億萬(wàn)個(gè)細(xì)胞構(gòu)成。Cellsexistinavarietyofshapesandsizes.Theymay,forexample,becube-shapedorflat.Scientistswhostudycellshavedeterminedthatasinglecellmaybeaslargeasatennisballorsosmallthatthousandswouldfitonthepointofaneedle.Theyolkofahen’seggisactuallyaverylargecell.Bycontrast,bacteriaeachoneofwhichisatinycell areamongthesmallestRegardlessofitsshapeorsize,everycellcontainsthe“machinery”neededtomaintainlife.Whilenormallycellsfunctionwithgreatefficiency,theyaresubjecttovariousdisordersthatresultindisease.究發(fā)現(xiàn)單獨(dú)一個(gè)細(xì)胞可以像網(wǎng)球一樣的大小，或小到幾千個(gè)細(xì)胞才能剛好填滿針頭。雞的蛋黃是一個(gè)非常大的單細(xì)胞。微小的細(xì)菌呢算是最小的細(xì)胞。不管是細(xì)胞大小或形狀的不同，每個(gè)細(xì)胞都有“需要存活的機(jī)制”。對(duì)每個(gè)正常的細(xì)胞，有效力的細(xì)胞，都存在許多問(wèn)題，能導(dǎo)致疾病。Thesizeofcellsisusuallymeasuredinmicrons.Amicronisamillionthofameter,andabout25,000micronsequaloneinch.Thesmallestbacteriaareabout0.2micronindiameter.Theaveragecellinthehumanbodyabouttenmicronsindiameterisaspeckbarelyvisiblewithouttheaidofamicroscope.微米微米等于一寸。最小的細(xì)菌的圓徑是0.2微米，肉眼勉強(qiáng)可以看得到，不需要顯微鏡的幫助。Thestudyofcellsisthebranchofbiologycalledcytology.Thesciencethatdealswithcellsonthesmalleststructuralandfunctionalleveliscalledmolecularbiology.研究關(guān)于“”是生學(xué)。Allcellsconsistofprotoplasm,the“l(fā)ivingjelly.”Theprotoplasmofatypicalcellformsthreevitalparts thecellmembrane,thecytoplasm,andthenucleus.Themembraneenclosestheothercellstructures.Muchofthechemicalworkofthecellisdoneinthecytoplasm,whichsurroundsthenucleus.Thenucleus,enclosedbyitsownmembrane,isthecontrolcenterofthecell.(seeFigure1-1)““心。thecellsMembrane細(xì)胞膜Cellscansurviveonlyinaliquidmediumthatbringsinfoodandcarriesawaywaste.Forone-celledorganismsthisfluidisanexternalbodyofwater theocean,alake,orastream.many-celledplantsandanimals,however,themediumispartoftheorganism inplants,thesap;inanimals,theblood.來(lái)說(shuō)，這就是細(xì)胞外的液體，如：大海里、河里或水流中。在對(duì)多細(xì)胞生物而言，這種媒介就是生物體的一部分，植物以汁液的形式，動(dòng)物以血液的形式。Thecellmembraneissemipermeable,ordifferentiallypermeablesomesubstancescanpassthroughit,butotherscannot.Thischaracteristicenablesthecelltoadmitusefulsubstancesandtorejectharmfulsubstancesfromthesurroundingfluidaswellasto forceout,orexcretewasteproductsintothefluid.個(gè)特殊性使細(xì)胞對(duì)細(xì)胞周圍只吸收了需要的物質(zhì)而排除掉有害的物質(zhì)，包括細(xì)胞內(nèi)的廢物通過(guò)液體化后排出細(xì)胞外。Thecellmembraneisanextremelythinbuttoughbandofproteinandphospholipidmolecules.Phospholipidsarechemicalssimilartostoredfat.Ontheevidenceofelectronmicrographs,biologistsbelievethatithasporesthroughwhichcertainsmallmoleculespassintact.Substancesprobablypassthroughthecellmembraneinseveralways.Smallchamberslocatedonthecellmembranecalledcaveolaegatherchemicalsignalsandchannelthemintothecells.Thecaveolaemayalsohelpdistributeproteinsthroughoutthecell.Largemoleculesenterthecellbyaprocesscalleddiffusion,inwhichtheymaybedissolvedbysubstancesinthecellmembrane.Theycanthenthroughthemembranewithoutdifficulty.Somecellstakeinlargemoleculesbymeansofpinocytosis.Inthisprocess,thecellmembraneformsapocketaroundlargemoleculesfloatingagainstit.Themolecule-and-fluid-filledpocketthenbreadsloosefromthemembranetobecomeabubblelikevacuole,andthevacuolethendriftsintothecytoplasm.Finally,thevacuolewallbreaksupandthemoleculesarereleasedintothecytoplasm.細(xì)胞膜是一種非常薄但確以很堅(jiān)固的蛋白磷脂膜形成。磷脂是一種類似于儲(chǔ)存的脂肪的蛋白物質(zhì)。通過(guò)電子顯微鏡，生物學(xué)家相信細(xì)胞膜有孔，使較小的物質(zhì)完全可以通過(guò)。物質(zhì)可通過(guò)多種方式從細(xì)胞膜進(jìn)入。細(xì)胞膜上的結(jié)構(gòu)，稱“小穴”，可接受化學(xué)信號(hào)再傳到細(xì)胞內(nèi)。小穴還可能參于細(xì)胞蛋白的分配。大的分子可通過(guò)“滲濾”進(jìn)入細(xì)胞內(nèi)，或被細(xì)胞膜內(nèi)體分解，使它們更容易的進(jìn)入細(xì)胞內(nèi)。有些細(xì)胞可通過(guò)“胞飲”方式吞飲較大的物質(zhì)。這個(gè)過(guò)程是通過(guò)細(xì)胞膜在大物質(zhì)形成了“帶”把它包圍著，將它以泡狀的“液泡”引入細(xì)胞質(zhì)，最后包圍解散，大物質(zhì)成功的進(jìn)入細(xì)胞內(nèi)。Thecytoplasm細(xì)胞質(zhì)Thecytoplasmismainlywater.Itswatercontentvariesfromaminimumofabout65percenttoamaximumofabout95percent.Thesolidsinthecytoplasmincludegranularproteins,carbohydrates,dropletsoffat,andpigments.Thecytoplasmisthusacolloidalsystem.細(xì)胞質(zhì)主水”6595碳水化合物、脂肪小滴和色素。細(xì)胞質(zhì)是膠體性的。Thecytoplasmmaybeeitherwateryorsyrupy,dependingontheconcentrationofsolidsdispersedinthefluid.Whenthesolidcontentdecreases,thesestructuresseemtovanish.Changesinconcentrationalsoproduceanapparentsteamingofthecytoplasmfromplacetoplacewithinthecell.Thisoccurs,forexample,whenfoodmoleculesenterthecell.細(xì)胞質(zhì)可能是水性或糖漿性，根據(jù)散在細(xì)胞質(zhì)內(nèi)固體的濃度。當(dāng)固體成分濃度增多，膜狀和纖維狀結(jié)果在細(xì)胞質(zhì)顯出。而當(dāng)固體成分濃度減少時(shí)，膜狀和纖維狀的結(jié)構(gòu)就消失。濃度的變化還可以表現(xiàn)細(xì)胞質(zhì)內(nèi)局部流動(dòng)的變化。食物分子進(jìn)入時(shí)可見(jiàn)。Mostofthecell’sconstantworkofkeepingaliveisperformedinthecytoplasm.Herefoodmoleculesarechangedintothematerialneededforenergyandmaterialsforgrowthorstiffeningofthecellmembranearemanufacturesneededbytherestoftheorganism.Forexample,plantcellscontainingchlorophyllmanufactureglucoseaplantfoodfromcarbondioxideandwater.大部分為了細(xì)胞存活的工作都在此處（細(xì)胞質(zhì)）完成的。在此處，食物物質(zhì)將被轉(zhuǎn)物的食物，從水和二氧化碳合成。Oneofthecytoplasm’skeyenergytransactionsoccursinthesausage-shapedmitochondria.Eachmitochondrionhasaninnerandanoutermembrane.Likethecellmembrane,themembranesofthemitochondrionaresemipermeable.Foodmoleculesthatpassintothecytoplasmaretakenintothemitochondriaandoxidized,orburned,forenergy.細(xì)胞質(zhì)能量轉(zhuǎn)換也是半滲透性。進(jìn)入線粒體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.胞漿網(wǎng)，在細(xì)胞質(zhì)中成的蛋白從胞漿網(wǎng)移動(dòng)到高爾基體儲(chǔ)存，為了后來(lái)分泌所用。Vacuolesdriftthroughthecytoplasmandusuallycarryfoodmoleculesinsolution.Lysosomesarestructuressomewhatsimilarinappearancetovacuolesbutdenser.Theyappeartohaveadigestivefunction.Eachlysosomeisfilledwithdigestiveenzymesandencasedinamembrane.Lysosomesarebelievedtobreakdownfoodsubstancesbroughtintothecellbypinocytosis.IthasbeensuggestedthattheGolgicomplexplaysapartintheformationoflysosomes.在細(xì)胞質(zhì)內(nèi)游動(dòng)的液泡一般是帶著食物分子的溶液。溶酶體是一種有點(diǎn)像液泡胞飲方式的大物質(zhì)。也認(rèn)為高爾基體對(duì)溶酶體的形成有關(guān)系。TheNucleus細(xì)胞核Nearthecenterofthecellisaroundishoroval-shapednucleus.Thenucleuscontrolsthegrowthanddivisionofthecell.Italsocontainsthestructuresthattransmithereditarytraits.細(xì)胞Enclosedbyatwo-layeredmembrane,thenucleuscontainsaliquidcallednucleoplasmaswellasstrandsofdeoxyribonucleicacid(DNA)coveredwithacoatingofprotein.AstrandofDNAconsistsofalongseriesofgenes,whicharetheunitsofheredityofplantsandanimals.Genesdeterminethecharacteristicsofacell.TheydothisbyregulatingtheproductionofRNA,whichinturncontrolsthemanufactureofspecificproteins.為“核質(zhì)（漿）”的液體和脫氧核糖核酸的蛋白層。脫氧核糖核酸縷是很長(zhǎng)的基因系列所組成的，它是植物和動(dòng)物的遺傳信息。基因決定了細(xì)胞的特征。它是通過(guò)調(diào)節(jié)核糖核酸，使核糖核酸產(chǎn)出特異的蛋白。Humancells,forexample,makeonlyproteinsuniquetohumanbeingsDNAstrandsareusuallytoothinlystrungouttobeseenwithanopticalmicroscope.Becausethestrandsarereadilystainedwithdyes,theyarecalledchromatin.Whenacellbeginstodivide,however,thechromatinthickensintotheformofchromosomes.白。脫氧核糖核酸縷一般都很細(xì)小過(guò)光學(xué)顯微鏡能觀察到。因?yàn)槊撗鹾颂呛怂峥|能夠染色“染色質(zhì)”。Anucleusnotundergoingdivisionhasatleastonenucleolus.ThenucleoluscontainsaconcentrationofRNA.BiologiststhinkRNAismadeinitiallyinthenucleusaccordingtoaDNA“blueprintandstoredthereuntilneededforproteinmanufacture.細(xì)胞核分化核仁不會(huì)減少，據(jù)脫氧核糖核酸的藍(lán)圖造出而藏在此處直到有蛋白合成的需要。thenucleusofanimalcellsisasphericalstructurecalledthecentrosome,fromwhichastersradiate.Thecentrosomecontainsapairofroddedstructurecalledcentrioles,whichusuallylieatrightanglestoeachother.Althoughcentriolesandcentrosomeshavenotbeenseeninplantcells,biologistsbelievethatplantcellscontainsimilarstructures.靠近動(dòng)物的細(xì)胞核的圓形結(jié)構(gòu)叫“中心體”，可見(jiàn)呈放射狀散發(fā)的星體。中心體內(nèi)含有一對(duì)棍狀結(jié)構(gòu)，稱為“中心?！保话愣夹纬烧_固定的角度。無(wú)法在植物細(xì)胞發(fā)現(xiàn)中心體和中心粒，但生物學(xué)家認(rèn)為植物應(yīng)該有存在類似功能的其他結(jié)構(gòu)。Tissues組織Cellsareorganizedintotissuesthatperformspecificfunctions.Thefourbasictissuetypesareasfollows:多細(xì)胞組成了組織，為了特異的功能。四種基本的組織：Epithelialtissuescoversandprotectsbodystructuresandlinesorgans,vessels,cavities.:覆蓋及保護(hù)著身體結(jié)構(gòu)和分清器官、導(dǎo)管和空腔。Connectivetissuessupportsandbindsbodystructures.Itcontainsfibersandothernonlivingmaterialbetweenthecells;includedarefattissues,cartilage,boneandblood.結(jié)締組織:骨、骨頭和血液。Muscletissuescontractstoproducemovement.Thethreetypesare：skeletalorvoluntarymusclethatmovestheskeleton;thecardiacmuscleoftheheart;andthesmoothmusclethatformsthewallsoftheabdominalorgans.Cardiacandsmoothmusclecanfunctionwithoutconsciouscontrolandarethusdescribedasinvoluntarymuscle.:通過(guò)收拾來(lái)產(chǎn)生道壁的肌肉。心機(jī)和平滑肌是非意識(shí)性，不隨意性肌肉。Nervoustissue——makesupthebrain,spinalcord,andnerves.Itcoordinatesandcontrolsbodyresponsesbytransmittingelectricalimpulses.神經(jīng)組織:通過(guò)動(dòng)作電位來(lái)超空身體。Thesimplesttissuesaremembranes.Mucousmembranessecretethickfluidcalledmucusthatprotectsunderlyingtissues.Serousmembranessecreteathin,wateryfluid.Theylinebodycavitiesandcoverorgans.作用。粘液組織分泌出較稀的粘液，起得身體導(dǎo)管的分界和覆蓋著各個(gè)器官。HumandiseasesInthispassageyouwilllearn:1.diseaseandpathology2.theclassificationofdiseases3.germs’invasionofthehumanbody4.thebody’sdefenseagainstinvasion5.thebody’simmunitytodiseasesThebriefsurveyofthehumanbodyinChapterOnehasgivenusaglimpseintotwodifferentstudiesthatareconsideredthefundamentalsofmedicalsciences,namelyanatomyandphysiology.However,thepictureisnotcompletewithoutconsideringpathology,thesciencethatdealswiththestructuralandfunctionalchangesproducedbythedisease.Infact,themodernapproachtothestudyofdisorderemphasizesthecloserelationshipofthepathologicalandphysiologicalaspectsandtheneedtounderstandthefundamentalsofeachintreatinganybodydiseases.理學(xué)與生理學(xué)基礎(chǔ)的重要性。Thenwhatisadisease?Itmaybedefinedasaconditionthatimpairstheproperfunctionofthebodyorofoneofitsparts.Everylivingthing,bothplantsandanimals,cansuccumbtodisease.People,forexample,areofteninfectedbytinybacteria,butbacteria,inturn,canbeinfectedbyevenmoreminuteviruses.那么什么是疾病呢？它可能被定義為正常的功能或是部分功能遭受損害時(shí)的一種狀態(tài)。每一種生物、植物和動(dòng)物，都會(huì)受制于疾病。例如，人Hundredsofdifferentdiseasesexist.Eachhasitsownparticularsetofsymptomsandsigns,cluesthatenableaphysiciantodiagnosetheproblem.Asymptomissomethingapatientcandetect,suchasfever,bleeding,orpain.Asignissomethingadoctorcandetect,suchasaswollenbloodvesseloranenlargedinternalbodyorgan.許多種疾病存在于世。每一種都有其特定的癥狀、征兆和線索，醫(yī)生能以此診斷疾病之所在。癥狀是病人自己就能覺(jué)察到的，比如，高燒、流血，或是疼痛。而征兆則是醫(yī)生能夠觀察到的，比如，血管擴(kuò)張或是體內(nèi)器官腫大。Diseasescanbeclassifieddifferently.Forinstance,anepidemicdiseaseisonethatstrikesmanypersonsinacommunity.Whenitstrikesthesameregionyearafteryearitisanendemicdisease.Anacutediseasehasaquickonsetandrunsashortcourse.Anacuteheartattack,forexample,oftenhitswithoutwarningandcanbequicklyfatal.Achronicdiseasehasaslowonsetandrunsasometimesyears-longcourse.Thegradualonsetandlongcourseofrheumaticfevermakesitachronicailment.Betweentheacuteandchronic,anothertypeiscalledsubacute.疾病可以劃分為不同的種類，例如，流行病是一種在某一社區(qū)內(nèi)侵襲許多人的疾病。當(dāng)它年復(fù)一年地襲擊同一社區(qū)，就成了一種地方病。急性病發(fā)作快，但病程短，舉個(gè)例子來(lái)說(shuō)，急性心臟病發(fā)作常常沒(méi)有前兆，而且會(huì)很快致命。慢性病發(fā)作則慢，但病程有時(shí)會(huì)長(zhǎng)達(dá)幾年之久。風(fēng)濕熱正是由于發(fā)病慢、病程長(zhǎng)而成為一種慢性失調(diào)病（慢性病性之間的另一種類型，就被稱為亞急性。Diseasescanalsobeclassifiedbytheircausativeagents.Forinstance,aninfectious,orcommunicable,diseaseistheonethatcanbepassedbetweenpersonssuchasbymeansofairbornedropletsfromacoughorsneeze.Tinyorganismssuchasbacteriaandfungicanproduceinfectiousdiseases.Socanviruses.Socantinyworms.Whateverthecausativeagentmightbe,itsurvivesinthepersonitinfectsandispassedontoanother.Sometimes,adisease-producingorganismgetsintoapersonwhoshowsnosymptomsofthedisease.Theasymptomaticcarriercanthenpassthediseaseontosomeoneelsewithoutevenknowinghehasit. 也不知情的情況下就把疾病傳染給了他人。Noninfectiousdiseasesarecausedbymalfunctionsofthebody.Theseincludeorganortissuedegeneration,erraticcellgrowth,andfaultybloodformationandflow.Alsoincludedaredisturbancesofthestomachandintestine,theendocrinesystem,andtheurinaryandreproductivesystems.Somediseasescanbecausedbydietdeficiencies,lapsesinthebody'sdefensesystem,orapoorlyoperatingnervoussystem.非傳染性疾病是由身體功能失調(diào)引起的組織退化、異常細(xì)胞生成，以及異常的血液生成和血液循環(huán)。當(dāng)然其中也包括胃、腸、內(nèi)分泌系統(tǒng)和泌尿生殖系統(tǒng)的紊亂。一些疾病也可能是由飲食不足、身體抵抗力下降、或是神經(jīng)系統(tǒng)工作不造成的。Disabilityandillnessescanalsobeprovokedbypsychologicalandsocialfactors.Theseailmentsincludedrugaddiction,obesity,malnutrition,andpollution-causedhealthproblems.心造成的健康問(wèn)題。Furthermore,athousandormoreinheritablebirthdefectsresultfromalternationsingenepatterns.Sincetinygenesareresponsibleforproducingthemanychemicalsneededbythebody,missingorimproperlyoperatinggenescanseriouslyimpairhealth.Geneticdisordersthataffectbodychemistryarecalledinbornerrorsofmetabolism.Someformsofmentalretardationarehereditary.而且，有上千種乃至為數(shù)更多的遺傳性出生缺陷是由于基因變化而造成的。由育遲緩就是因遺傳而造成的。HowGermsInvadetheBody病菌是怎樣侵襲身體Humansliveinaworldwheremanyotherlivingthingscompeteforfoodandplacestobreed.Thepathogenicorganisms,orpathogens,oftenbroadlycalledgerms,thatcausemanydiseasesareabletoinvadethehumanbodyanduseitscellsandfluidsfortheirownneeds.Ordinarily,thebody'sdefensesystemcanwardofftheseinvaders.御系統(tǒng)能夠阻止這些入侵者。Pathogenicorganismscanenterthebodyinvariousways.Somesuchasthesethatcausethecommoncold,pneumonia,andtuberculosisarebreathedin.Otherssuchasthosethatcausevenerealdiseasesenterthroughsexualcontactofhumanbodies.Stillotherssuchasthosethatcausehepatitis,colitis,cholera,andtyphoidfever-getinthebodythroughcontaminatedfood,waterorutensils.進(jìn)入體內(nèi)的，比如那些引起肝炎、霍亂和傷寒熱的病原體。Insectscanspreaddiseasebyactingasvectors,orcarriers.Fliescancarrygermsfromhumanwasteorothertaintedmaterialstofoodandbeverages.Germsmayalsoenterthebodythroughthebiteofamosquito,louse,orotherinsectvector.蚊子、虱子或其它媒介動(dòng)物的叮咬，病菌也可能進(jìn)入體內(nèi)。HowtheBodyFightsDisease身體是怎樣抵抗疾病的Asafirstlineofdefense,ahealthybodyhasanumberofphysicalbarriersagainstinfection.Theskinandmucousmembranescoveringthebodyorliningitsopeningsofferconsiderableresistancetoinvasionbybacteriaandotherinfectiousorganisms. Ifthesephysicalbarriersareinjuredorburned,infectionresistancedrops.Inminorcases,onlyboilsorpimplesmaydevelop.Inmajorcases,however,largeareasofthebodymightbecomeinfected.健康的身體有許多屏障來(lái)抵御感染的發(fā)生。覆蓋在體表或者器官開(kāi)口處的皮膚和粘膜能在很大程度上抵抗細(xì)菌或其它感染體的入侵。如果這些屏障遭到了損壞或燒傷，身體對(duì)感染的抵抗力就會(huì)下降。在一些病情較輕的病例中，疥子和小膿胞可能會(huì)發(fā)生。在病情較重的病例中，身體的大面積區(qū)域則可能會(huì)被感染。Breathingpassagesareespeciallyvulnerabletoinfection.Fortunately,theyarelinedwithmucus-secretingcellsthattraptinyorganismsanddustparticles.Also,minutehairscalledcilialinethebreathingpassages,wavelikeafieldofwheat,andgentlysweepmatteroutoftherespiratorytract.Inaddition,foreignmatterinthebreathingpassagescanoftenbeejectedbynoseblowing,coughing,sneezing,andthroatclearing.Unfortunately,repeatedinfection,smokingandothercausescandamagetherespiratorypassagewaysandmakethemmoresusceptibletoinfection.抽煙或其它別的原因會(huì)損壞呼吸道，并且使它們?nèi)菀资艿礁腥尽anypotentialinvaderscannotstandbodytemperature(98.6°For37°C).Eventhosethatthriveatthattemperaturemaybedestroyedwhenthebodyassumeshigher,fevertemperatures.98.637燒溫度，甚至一些在先前溫度下能蓬勃繁殖的病菌也可能會(huì)因此而遭到毀滅。Waxintheouterearcanalsandtearsfromeyeductscanslowthegrowthofsomebacteria.Andstomachacidcandestroycertainswallowedgerms.緩一些細(xì)菌的生長(zhǎng)速度，而胃酸也能毀掉某種吞食進(jìn)去的病菌。Thebody'ssecondlineofdefenseisinthebloodandlymph.Certainwhitebloodcellsflocktoinfectedareasandtrytolocalizetheinfectionbyformingpus-filledabscesses.Unlesstheabscessbreaksandallowsthepustodrain,theinfectionislikelytospread.Whenthishappens,theinfectionisfirstblockedbylocallymphglands.Forexample,aninfectioninthehandtravelsupthearm,producingredstreaksandswollen,tenderlymphglandsinthearmpit.Unlesstheinfectionisbroughtundercontrol,itwillresultinbloodpoisoning. 痛。如果不及時(shí)控制住感染的上傳，將會(huì)導(dǎo)致血液中毒。Phagocytesarelocatedatvarioussitestominimizeinfection.Onetypeinthespleenandliverkeepsthebloodclean.Othersinsuchhigh-riskareasasthewallsofthebronchiandtheintestinesremovecertainbacteriaandshatteredcells.得感染的機(jī)會(huì)變小。位于肝脾內(nèi)的一類能使身體的血液保持干凈。其它的位于像支氣管壁和腸壁這樣高危險(xiǎn)區(qū)的類型能清除某類細(xì)茵和已解體的細(xì)胞。HowWeBecomeImmunetoDisease我們是怎樣變得對(duì)疾病有免疫力的Thebodyhasaspecialwayofhandlinginfection.Ithasasystemthatfendsoffthefirsttracesofaninfectioussubstanceandthen,througha"memory,"givesthebodyalong-lastingimmunityagainstfutureattacksbythesamekindofinvader.統(tǒng)，能夠一開(kāi)始就阻止感染性物質(zhì)的侵襲，然后通過(guò)“記憶”，它能給身體—個(gè)長(zhǎng)期的免疫力來(lái)抵抗將來(lái)由同種入侵者引起的侵襲。Manysubstancescouldharmthebodyiftheyeverenteredit.Thesesubstances,orantigens,rangefrombacteriaandpollentoatransplantedorgan(viewedbythebodyasaninvader).Tofightthemthebodymakesspecialchemicalsknownas體視