醫(yī)學(xué)英語(yǔ)(閱讀一分冊(cè))翻譯與答案

./Chapter1Passage1HumanBodyInthispassageyouwilllearn:1.Classificationoforgansystems2.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,并牽動(dòng)骨胳肌,引起各種運(yùn)動(dòng).人體有206根骨頭.骨形態(tài)不一,有長(zhǎng)的、短、立方的、扁的及不規(guī)則的.許多長(zhǎng)骨里有一個(gè)內(nèi)層間隙,里面充填著骨髓,這即是血細(xì)胞的制造場(chǎng)所.Ajointiswherebonesarejoinedtogether.Theconnectioncanbesoclosethatnomovementispossible,asisthecaseintheskull.Otherkindsofjointspermitmovement: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,whichhelpsmaintainaconstantbodytemperature.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),如走路,運(yùn)動(dòng)軀體某個(gè)部位,如彎曲手指.心臟收縮和平滑肌收縮就不是被意識(shí)所控制的.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.循環(huán)系統(tǒng)：機(jī)體的所有部分需要營(yíng)養(yǎng)物質(zhì)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.心臟是一塊被分為幾乎對(duì)等兩半的肌肉.一半吸收來(lái)自肺部的血液,并將血液運(yùn)送到機(jī)體的其余部位,另一半使流經(jīng)全身的血液回流人肺.心臟收縮時(shí),動(dòng)脈把全身血液輸送到毛細(xì)血管.靜脈輸送血液返回心臟.Alsofunctioningincirculationisthelymphaticsystem.Someofthefluidthatsurroundscellsdoesnotreenterthebloodvesselsdirectly.Thisfluid,calledlymph,returnstotheheartbywayofanothersystemofchannels-thelymphvessels.Lymphnodesalongthesevesselsfilterthefluidbeforeitreenterstheblood.Thespleenisalargelymphaticorganthatfilterstheblood.淋巴系統(tǒng)也是循環(huán)系統(tǒng)的一個(gè)組成部分.一些細(xì)胞周圍的體液不是直接回流入血管通道,這種體液叫淋巴液,它是流經(jīng)另一個(gè)管道系統(tǒng)——淋巴管而回流人心臟.沿淋巴管的淋巴結(jié)將淋巴液過濾,過濾后再回流人血液.脾是一個(gè)過濾血液的大淋巴器官.Therespiratorysystemtakesinoxygenfromtheairandexpelscarbondioxideandwatervapor.Airentersthenoseandmouthandtravelsthroughthelarynx,andtrachea.Thetracheadividestoentereachofthetwolungsandthendividesmorethan20timestoformaverylargenumberofsmallairspaces.Oxygenfromtheairentersthebloodthroughcapillariesinthewallsoftheseairspaces,andthebloodreleasecarbondioxideintotheairspacestobeexhaled.呼吸系統(tǒng)從空氣中攝取氧氣,并將二氧化碳、水蒸氣排出體外.空氣經(jīng)鼻腔、口腔人喉管、氣管.氣管分成左右支氣管,各連結(jié)左右肺,左右支氣管再分枝20多次,在終端形成大量微小的肺泡.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.消化系統(tǒng)是一個(gè)從口腔直到肛門的管道.食物和液體在消化道里被吸收,在腸道里移動(dòng)時(shí),被分解成小分子物質(zhì)后再進(jìn)入循環(huán)系統(tǒng).這種分解,即消化,是一個(gè)機(jī)械過程,也是一個(gè)化學(xué)過程.Foodentersthroughthemouth,wherechewingandsalivastarttobreakitupandmakeiteasiertoswallow.Next,thefoodtravelsdownthroughtheesophagustothestomach.Contractionsofthestomach'smuscularwallcontinuetobreakdownthefoodmechanically,andchemicaldigestioncontinueswhenacidandenzymesaresecretedintothestomachcavity.食物進(jìn)入口腔里,咀嚼和唾液開始將食物粉碎,使之便于吞咽.接著,食物經(jīng)食管人胃.胃肌壁的收縮繼續(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),膽汁有助于脂肪消化.一個(gè)成年人的小腸有21英尺〔6.4米長(zhǎng).小腸的大部分腸段用來(lái)吸收消化過程中釋放的營(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,或結(jié)腸,它大約有12英尺〔3.7米長(zhǎng).大腸是小腸的兩倍多寬.大部分液體在大腸內(nèi)被吸收,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、鉀的正常水平.身體是通過讓’腎過濾血液來(lái)做到這一點(diǎn)的.腎是兩個(gè)有效的過濾器官,它濾出各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.從腎流出的液體,即尿,通過輸尿管人膀胱.膀胱起貯存尿液的作用,直到尿經(jīng)膀胱另一端的管道排出.Theendocrinesystem.Thetwosystemsthatcontrolbodyactivitiesaretheendocrinesystemandthenervoussystem.Theformerexertsitscontrolbymeansofchemicalmessengerscalledhormones.Hormonesareproducedbyavarietyofendocrineglands,whichreleasethehormonesdirectlyintothebloodstream.內(nèi)分泌系統(tǒng).內(nèi)分泌和神經(jīng)是調(diào)控機(jī)體活動(dòng)的兩個(gè)系統(tǒng),前者依靠其化學(xué)信使——激素發(fā)揮作用.激素是由各種內(nèi)分泌腺體制造,并直接被釋放入血流Amajorglandisthepituitary,whichislocatedunderthebraininthemiddleofthehead.Itproducesatleasteighthormones,whichaffectgrowth,kidneyfunction,anddevelopmentofthesexorgans.Becausesomeofthepituitary'shormonesstimulateotherglandstoproducetheirownhormones,thepituitarycalledthemastergland.腦垂體是一個(gè)主要腺體,它位于頭中部腦下方.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,andtheregionsthatdirectvoluntarymuscularactivitiesofthearmsandlegs.Performedherearethehigherfunctionsofintegratingandprocessinginformation.神經(jīng)系統(tǒng)——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、聽覺、觸覺、嗅覺及味覺中心,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.腦通過神經(jīng)收集并傳送信息,許多神經(jīng)部分地分布在脊髓里.脊髓由脊柱保護(hù).在機(jī)體每一級(jí),神經(jīng)傳人、傳出脊髓,往返于臂、腿、軀體.這些神經(jīng)輸送來(lái)自各種感覺器官的信息.信息經(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.它也分泌男性激素、睪酮,以此調(diào)節(jié)胡須、陰毛、深沉嗓音極其他成年男子身體發(fā)育的特征.Thefemaleproductivesystemisresponsibleforproducingandtransportingova<thefemalesexcells>,eliminatingovafromthebodywhentheyarenotfertilizedbysperm,nourishingandprovidingaplaceforgrowthofanembryowhenanovumisfertilizedbysperm,andnourishinganewbornchild.Thefemalereproductivesystemalsoproducesthefemalesexhormones,estrogenandprogesterone,whichregulatethedevelopmentofbreastsandotherbodilycharacteristicsofthematurefemale.女性生殖系統(tǒng)產(chǎn)生、輸送卵子〔女性性細(xì)胞,將未受精的卵子排出體外,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.女性生殖系統(tǒng)也分泌女性性激素——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'stemperaturecloseto37°C,heatisconservedbyreducingbloodflowthroughtheskinorisexpendedbyincreasingbloodflowandbyevaporationofsweatfromtheskin.Hairandnailsareaccessorystructuresoftheskin.皮膚是保護(hù)肌體內(nèi)層結(jié)構(gòu)的完整層,也是機(jī)體的最大器官.皮膚防御外來(lái)侵襲,防止過多水分蒸發(fā).皮膚上的神經(jīng)提供觸覺信息.皮膚也能將體溫維持到98.6華氏度〔約37攝氏度.通過皮膚的血流量降低時(shí),熱量就被儲(chǔ)存起來(lái),通過皮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’sstateofinternalstability,termedhomeostasis.Nowlet’sbeginourdiscussionwithcells,thesmallestunitoflivingmatterthatcanexistbyitself.細(xì)胞構(gòu)成組織,組織構(gòu)成器官,器官又進(jìn)一步構(gòu)成系統(tǒng).人體的每個(gè)系統(tǒng)都有其特定功能,但是,請(qǐng)記住這里:機(jī)體是作為一個(gè)整體來(lái)發(fā)揮作用的,沒有哪個(gè)系統(tǒng)能夠獨(dú)立于其他系統(tǒng)而存在,是整體系統(tǒng)共同作用保持了機(jī)體內(nèi)部的穩(wěn)定狀態(tài),即體內(nèi)平衡.現(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)胞開始,我們能夠從最簡(jiǎn)單到最復(fù)雜的水平來(lái)研究機(jī)體.所有人體的功能都來(lái)自億萬(wàn)個(gè)特定細(xì)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,bacteriaeachoneofwhichisatinycellareamongthesmallestcells.Regardlessofitsshapeorsize,everycellcontainsthe"machinery"neededtomaintainlife.Whilenormallycellsfunctionwithgreatefficiency,theyaresubjecttovariousdisordersthatresultindisease.細(xì)胞有很多種形狀和大小.列如：有可能是立方形或扁形的.科學(xué)家的研究發(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,都存在許多問題,能導(dǎo)致疾病.Thesizeofcellsisusuallymeasuredinmicrons.Amicronisamillionthofameter,andabout25,000micronsequaloneinch.Thesmallestbacteriaareabout0.2micronindiameter.Theaveragecellinthehumanbodyabouttenmicronsindiameterisaspeckbarelyvisiblewithouttheaidofamicroscope.細(xì)胞的大小是以"微米"為長(zhǎng)度單位.微米是一米的一百萬(wàn)分之一,25000微米等于一寸.最小的細(xì)菌的圓徑是0.2微米.人體正常細(xì)胞的評(píng)價(jià)圓徑約十微米,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"細(xì)胞"是生物學(xué)的分支,成為細(xì)胞生物學(xué).在最微小水平針對(duì)細(xì)胞的結(jié)構(gòu)及功能的研究成為分子生物學(xué).Allcellsconsistofprotoplasm,the"livingjelly."Theprotoplasmofatypicalcellformsthreevitalpartsthecellmembrane,thecytoplasm,andthenucleus.Themembraneenclosestheothercellstructures.Muchofthechemicalworkofthecellisdoneinthecytoplasm,whichsurroundsthenucleus.Thenucleus,enclosedbyitsownmembrane,isthecontrolcenterofthecell.<seeFigure1-1>所有細(xì)胞都是以"原生質(zhì)",又稱"生命膠質(zhì)"所形成的.典型細(xì)胞的原生質(zhì)形成了三個(gè)重要部分,細(xì)胞膜、細(xì)胞質(zhì)和細(xì)胞核.細(xì)胞膜圈住了細(xì)胞的其他結(jié)構(gòu).大部分的化學(xué)反應(yīng)都在細(xì)胞核周圍,細(xì)胞質(zhì)完成的.被自己的膜包圍的細(xì)胞核是細(xì)胞的控制中心.thecellsMembrane細(xì)胞膜Cellscansurviveonlyinaliquidmediumthatbringsinfoodandcarriesawaywaste.Forone-celledorganismsthisfluidisanexternalbodyofwatertheocean,alake,orastream.Formany-celledplantsandanimals,however,themediumispartoftheorganisminplants,thesap;inanimals,theblood.細(xì)胞只能存活在能供養(yǎng)分又能排除廢物的液體媒介中.對(duì)單細(xì)胞生物來(lái)說,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.Thischaracteristicenablesthecelltoadmitusefulsubstancesandtorejectharmfulsubstancesfromthesurroundingfluidaswellastoforceout,orexcretewasteproductsintothefluid.細(xì)胞膜是半滲透性或區(qū)別性的滲透膜,即某些物質(zhì)能滲透.這個(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.物質(zhì)可通過多種方式從細(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"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"胞飲"方式吞飲較大的物質(zhì).這個(gè)過程是通過細(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)主要成分是"水".水分含量有百分之65到最高,百分之95.細(xì)胞質(zhì)內(nèi)的固體包括蛋白顆粒、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.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)化成提供細(xì)胞能量的材料和提供細(xì)胞生長(zhǎng)的材料,或細(xì)胞膜的增強(qiáng)劑所生產(chǎn).多細(xì)胞植物的細(xì)胞質(zhì)還是生產(chǎn)了對(duì)其他生物提供食物的物質(zhì).列如：植物葉綠素所產(chǎn)生的葡萄糖,植物的食物,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)換的要點(diǎn)發(fā)生在錐狀形的線粒體.每個(gè)線粒體都有內(nèi)膜和外膜.像細(xì)胞膜一樣,線粒體的膜也是半滲透性.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)中由膜所形成管狀的網(wǎng).有些生物學(xué)家認(rèn)為這是一種連續(xù)性結(jié)構(gòu),始點(diǎn)為細(xì)胞膜,在細(xì)胞膜內(nèi)扭絞,終點(diǎn)為細(xì)胞核的膜.分布于胞漿網(wǎng)包括細(xì)胞質(zhì)中某處的是核糖體.這些小顆粒是核糖核酸所形成的.蛋白質(zhì)是在核糖體合成的.高爾基體是膜狀囊包堆成層形成的.新合成的蛋白從胞漿網(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)像液泡的結(jié)構(gòu),但較稠.它是用來(lái)消化的.每個(gè)溶酶體的膜內(nèi)都是添裝著消化酶.我們認(rèn)為它是消化通過"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)胞的中央,圓形或橢圓形的就是細(xì)胞核.細(xì)胞核控制細(xì)胞的生長(zhǎng)和分化.也裝著遺傳信息.Enclosedbyatwo-layeredmembrane,thenucleuscontainsaliquidcallednucleoplasmaswellasstrandsofdeoxyribonucleicacid<DNA>coveredwithacoatingofprotein.AstrandofDNAconsistsofalongseriesofgenes,whicharetheunitsofheredityofplantsandanimals.Genesdeterminethecharacteristicsofacell.TheydothisbyregulatingtheproductionofRNA,whichinturncontrolsthemanufactureofspecificproteins.被兩層膜圈住著,細(xì)胞核內(nèi)含有稱為"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.列如：人的細(xì)胞,只產(chǎn)出人獨(dú)特?fù)碛械牡鞍?脫氧核糖核酸縷一般都很細(xì)小過光學(xué)顯微鏡能觀察到.因?yàn)槊撗鹾颂呛怂峥|能夠染色后部分被染,稱"染色質(zhì)".細(xì)胞分化過程中,染色體拾起變厚形成了"染色體".Anucleusnotundergoingdivisionhasatleastonenucleolus.ThenucleoluscontainsaconcentrationofRNA.BiologiststhinkRNAismadeinitiallyinthenucleusaccordingtoaDNA"blueprint"andstoredthereuntilneededforproteinmanufacture.細(xì)胞核分化核仁不會(huì)減少,最少要有一個(gè)核仁.核仁含有豐富的核糖核酸.生物學(xué)家認(rèn)為核糖核酸原本在核仁里,根據(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"中心粒",一般都形成正確固定的角度.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,andcavities.上皮組織: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:支柱和聯(lián)結(jié)著身體結(jié)構(gòu).包括細(xì)胞之間的纖維和其它無(wú)生物結(jié)構(gòu).包括脂肪組織、軟骨、骨頭和血液.Muscletissuescontractstoproducemovement.Thethreetypesare：skeletalorvoluntarymusclethatmovestheskeleton;thecardiacmuscleoftheheart;andthesmoothmusclethatformsthewallsoftheabdominalorgans.Cardiacandsmoothmusclecanfunctionwithoutconsciouscontrolandarethusdescribedasinvoluntarymuscle.肌肉組織:通過收拾來(lái)產(chǎn)生動(dòng)作.分為三種：骨骼肌,作用于一般骨骼移動(dòng).心機(jī),心臟的肌肉.平滑肌,形成胃腸道壁的肌肉.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:組成大腦、脊椎和神經(jīng).它是通過動(dòng)作電位來(lái)超空身體.Thesimplesttissuesaremembranes.Mucousmembranessecretethickfluidcalledmucusthatprotectsunderlyingtissues.Serousmembranessecreteathin,wateryfluid.Theylinebodycavitiesandcoverorgans.最簡(jiǎn)單的組織就是膜.粘液膜分泌出粘稠的膠液,起得組織保護(hù)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.第一章中,通過對(duì)人體的概論,即解剖學(xué)與生理學(xué),我們對(duì)兩種被認(rèn)為是醫(yī)學(xué)基礎(chǔ)的不同學(xué)科有了一個(gè)大致的印象.然而如果我們不考慮病理學(xué),這門涉及由疾病帶來(lái)的結(jié)構(gòu)和功能變化的學(xué)科,上述的人體概論就不是完整的.實(shí)際上,現(xiàn)代對(duì)疾病的研究方法強(qiáng)調(diào)了病理學(xué)與生理學(xué)方面的密切關(guān)系,強(qiáng)調(diào)了我們?cè)谥委熑魏稳梭w疾病方面需要了解病理學(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,人類常常被微小的細(xì)菌所感染,但是,反過來(lái)說,細(xì)菌又能夠被甚至更加微小的病毒所感染.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,急性心臟病發(fā)作常常沒有前兆,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.而介于急性與慢性之間的另一種類型,就被稱為亞急性.Diseasescanalsobeclassifiedbytheircausativeagents.Forinstance,aninfectious,orcommunicable,diseaseistheonethatcanbepassedbetweenpersonssuchasbymeansofairbornedropletsfromacoughorsneeze.Tinyorganismssuchasbacteriaandfungicanproduceinfectiousdiseases.Socanviruses.Socantinyworms.Whatev