专业英语 Unit 16教案学习资料

PAGE6PAGE6UnitSixteenPATHOLOGICPROCESSESINVOLVINGTHEORALMUCOSATheoralmucousmembranereactstovariousformsofinjuriousstimulianddevelopslesionsifthestimuliornoxiousinfluencesaresufficienttoproducedisease.Lesionsoccurringontheoralmucosamaybeofseveraldistinctclinicalforms,andasimilartypeofgrosslesionmaybeproducedbyalargevarietyofentirelydifferentagents.Theappearanceofthegrosslesionisusuallyinsufficientforadequatediagnosis.Distributionofthelesions,clinicalhistory,andpasthistorymayhavesomediagnosticvalue,butmicroscopicexaminationisoftennecessaryforexactdiagnosis.Themicroscopicfeaturesofalesionmaybenonspecific,anddiagnosiscanbemadeonlybypainstakingcorrelationofgrossappearance,clinicalhistory,andmicroscopicfindings.Ingeneral,thediagnosisoforallesionsdependsuponanevaluationofbothclinicalandmicroscopicfeatures.GROSSORCLINICALLESIONSEssentially,alldiseasesoftheoralmucosaaremanifestedclinicallybytheappearanceofgrosslyvisibleormacroscopiclesions.Theselesionscompriseasurprisinglysmallnumberofbasictypesorforms:macule,papule,plaque,vesicle,bulla,pustule,ulcer,erosion,nodule,tumor,atrophicarea.Macule.Amaculeisacircumscribed,non-raisedareaofalteredcolorationvaryinginsizefromapinheadtoseveralcentimetersindiameter.Maculesareusuallydeeperincolorthanthesurroundingnormalmucosaandmaybered,red-brown,orbrown-black.Amaculareruptionorrashmayrepresentpunctatehemorrhagesorpetechiaeasseeninscurvyorthrombocytopenicpurpura,melanindepositionasinAddison'sdisease,orsmallvascularmalformationsasinhereditarytelangiectasia.Maculesmayvaryinshapefromcirculartoovoidtosomewhatlinear.Papule.Apapuleisasmall,circumscribed,solid,elevatedareavaryinginsizefromapinheadto5mm.Thebaseisroundorovoid,andthesurfaceconfigurationmaybepointed,rounded,orflattened.Apapulareruptionontheoralmucosausuallyconsistsoflargenumbersofindividualpinbeadlesionsarrangedinvaryingpatterns.Thecolorofpapulesonoralmucousmembraneisusuallygray-white,andthegrosslesioncomposedofnumbersofpapulesmaybewhite.Lichenplanus,aninflammatorydermatosis,appearsasatypicalpapulareruptionoftheoralmucosa,withpapulesarrangedinlacelike,plaquelike,orevenannularpatterns.Plaque.Aplaqueisasmallorlarge,raised,firm:clearlydemarcatedareaofgrayorwhitecoloration.Thesurfacetexturemayberelativelysmoothorroughandpebbled.Cracksorfissuresmaydividethelesion.Leukoplakia,carcinoma,anddiscoidlupuserythematosusmayappearasplaques.Multiple,closelyplacedpapulesmayresembleaplaquesuperficially,butcarefulexaminationwithamagnifyingglasswillrevealthepunctatelesions,suchaslichenplanus,ratherthanthecontinuousplaquelesion.Vesicle.Avesicleisasmall(2to5mm),circumscribed,elevatedlesioncomposedofathinsurfacecoveringoverlyingandcontaininganaccumulationoffluid.Avesiculareruptionmayconsistofasinglelesionormultiplelesionsindifferentstagesofformationandhealing.Thecoveringorvesicularmembranemaybethinanddelicateorthick,dependinguponwhetherthevesicleissubepithelialorintraepithelial.Thelattertypehasathincoveringsinceonlypartoftheepitheliumformsthevesicularmembrane.Thefluidmaybeclearorslightlyred,dependingupontheseverityoftheinflammatoryreactionatthebaseofthevesicle.Asthevesicularmembraneruptures,anulcerforms.Vesicalareruptionsmaybeseeninsuchdiverseconditionsasviralinfections,drugreactions,burns,andvesiculardermatoses.Bulla.Abullaisalarge,vesicular-typelesionranginginsizefrom5mmtoseveralcentimeters.Theoutercoveringofthebullaorblebmaybethinorrelativelythick,dependinguponthesubepithelialorintraepithelialcharacterofthelesion.Thecoveringmembraneofthebullamaybetenseorlax,dependingupontheamountoffluid.Abullouslesionmaydevelopdirectlyormayformfromtheunionofseveralvesicleseruptingclosetogether.Bullaearecharacteristicallyseeninsuchdiseasesaspemphigusandpemphigoid.Bullaemayalsoappearinsuchcharacteristicallyvesiculareruptionsaserythemamultiformeandherpeticstomatitis.Duringeruptionsusuallyinvolvebothvesiclesandbullae.Pustule.Apustuleisavesiculartypeoflesioncontainingpurulentmaterialinsteadofclearfluid.Pustulesonoralmucosaareunusualbut.appearinsuchconditionsaspyostomatitis.Ulcer.Anulcerisadefectorbreakincontinuityoftheepithelialcomponentofpunched-outareaexists.Theflooroftheulceriscomposedofconnectivetissueandfibrinwithpolymorphonuclearleukocyteinfiltration.Thelossofepitheliumresultsinanacuteinflammatorylesion.Anulcermaybesmall(2mm)orquitelarge(severalcentimeters).Theedgesofanulcermayberaggedorsharp,maybeundermined,asintuberculosis,orraisedandindurated,asinmalignanttumors.Usually,ulcersareround,butelongatedulceratedareasmayoccur,particularlyasaresponsetomechanicalorchemicaltrauma.Theflooroftheulcermayappearyellowandpurulent,reddened,orgray-white.Ulcersmayresultfromtheruptureofvesiclesorbullae.Varyingamountsoferythemamayappearattheperipheryoftheulcer.Ulcerstendtobepainful.Erosion:Anerosionisashallowdefectinmucosarepresentinglossofepitheliumdowntobutnotincludingthestratumgerminativum.Erosionsofthemucosaareusuallyproducedbymechanicaltrauma;theymayhavealinearoutlinewithindistinctmargins.Theyappearredbecause,withthelossofamajorportionofepithelium,thevascularityoftheunderlyingconnectivetissuebecomesmorevisible.Erosionsmaybepainful.Nodule.Anoduleisasolidelevatedlesionofthemucosa,varyinginsizefrom5mmto2cm.Anoduleisformedbyamassofconnectivetissueforcingtheoverlyingepitheliumoutwardtoproduceasurfacelesion.Fibromaandnevusaretypicalexamplesofnodules.Tumor.Atumorisasolidgrowthofvaryingsizethatarisesfrommucosaandprojectsoutward.Theselesionsincludetrueneoplasmswithspecifichistopathologicfeaturesandtumorlikelesionssuchasgranulomapyogenicumandangiogranuloma.Truetumorsmaybebenignormalignant.Grossfeaturesareentirelyinsufficientforthedifferentiationofbenignandmalignantlesions,andabiopsyspecimenforhistologicstudyismandatory.Certainclinicalfeaturesmaybehelpful,benigntumorstendtohaveamoreregularsurfaceandarerelativelymovableuponpalpation;malignanttumorstendtobefixedtoadjacenttissueandoftenhaveirregularandulceratedsurfaces.However,clinicalcriteriaaretotallyinadequatefordiagnosisoftumorlikelesions.Atrophy.Areasofatrophymayappearreddenedbecausetheepitheliumisthinandtheconnectivetissuevascularityisclearlymanifested.Theareamaybeslightlydepressed.Specialepithelialstructuresmaybereplacedbyathinepithelium.Forexample,atrophyoflingualpapillaeresultsinasmooth,redtonguesurface.OtherLesions.Certaingrosslesionsthatoccuronskinarenotcharacteristicallyseenonoralmucosa.Amongthesearescars,crusts(driedexudateoverlyinganulceratedarea),fissures(cracksresultingfromdrying),andexcoriations(self-inflictedtraumatizedareas).DISTRIBUTIONANDDURATIONOFLESIONSInadditiontothetypeoflesionpresentinagivencase,thedistributionofthelesionmaybesignificantandmayaidinestablishingatentativediagnosis.Forexample,aneruptionofvesiclesintheposteriorareaofthemouthandoropharynxmightsuggestherpangina,whereasinvolvementoftheanteriorareaofthemouthandgingivamightsuggestherpeticstomatitis.Severevesicularandbullouslesionsonthelabialmucosamightindicateerythemamultiforme.Thedurationoflesionsmayalsobesuggestiveofcertainconditions.Ahistoryofarecurrentpatternmaybevaluableindetectingaproblemsuchasaphthousstomatitis.HIBTOPATHOLOGYOFMUCOSALLESIONSThemicroscopicpictureofmucousmembranediseaseisrarelydiagnosticinitself,butitmaypresentcertainfeaturessuggestiveoforconsistentwithknowndiseasepatterns.Thevarietyofpossiblealterationsaffectingepitheliumandconnectivetissueislimited.Allchangesfromnormalmustberecordedineachcase,andtheassembledfactsmaypointtoaspecificdiagnosis.Incertainlesionssuchasmalignanttumors,adefinitivediagnosiscanbeestablishedbymicroscopicstudy.Histopathologicfeaturescommonlyseeninmucousmembranediseasesarediscussedhereinrelationtoepitheliumandconnectivetissue.EpithelialAlterationsHyperkeratosis.Thisconditionischaracterizedbyawideningorthickeningofthestratumcorneum.Clinically,hyperkeratosisresultsinawhitelesion.Theopacityandwhitenessofthelesionarerelatedtotheamountofkeratinization.Paraketatosis.Inparakeratosis,thestratumcorneumdemonstratespersistenceofnucleiandvaryingdegreesofthickeningthatmayequalthatofhyperkeratosis.Thisreactionmayrepresentanabnormallyrapidkeratinizationprocess.Clinically,itusuallyresultsinawhitelesion.Acanthosis.Inthiscondition,thestratumspinosumbecomeswider.Acanthosissignifiesepithelialhyperplasia;itmayexistwithorwithouthyperkeratosis.Spongiosis.Thistermisusedtosignifyintercellularedemaoftheepithelium,inwhichintercellularbridgesofthestratumspinosumbecomemoreprominent.HydropicDegeneration.Becauseofedemaanddegenerationofcellsofthestratumgerminativum,thenucleiarereplacedbyclearspaces.Entirecellsgraduallydegenerate,andtheepithelialconnectivetissueboundaryispoorlydefined.Acantholysis.Thislesioniscausedbyaseparationofcellsinthestratumspinosumsothatanintraepithelialsplitoccur,whichleadstotheformationofanintraepithelialvesicle.ExtensionofRetePegs.Becauseofelongation,theretepegsextendintounderlyingconnectivetissue.PseudoepitheliomatousHyperplasia.Inthiscondition,theretepegsextendfardownward,usuallyaccompaniedbyacanthosis,tocreateatissuepatternsimilartocarcinoma.However,thecellsareessentiallynormalinsize,shape,andchromaticity.Dyskeratosis.Thislesionshowsanabnormalorientationordevelopmentofepithelialcells.Dyskeratosisormalignantdyskeratosissignifiesapremalignantepithelialchange,andthecellsshowsuchalterationsashyperchromatism,changesinpolarity,andincreasednuclearsizewithprominenceofthenucleoli.Mitoticfiguresmayalsobeincreased.AbenigntypeofdyskeratoticchangeorbenigndyskeratosisoccursinconditionssuchasmolluscumcontagiosumandDarier'sdisease.Generally,however,thetermdyskeratosisisusedonlyforthemalignantvariety,torepresentapremalignantlesion.Necrosis.Necrosisreferstodestructionofepitheliumandreplacementbyanamorphousmassoftissue.Necrosisisusuallyproducedbychemicalactionorbybacterialactivity,asinfusospirochetaldisease.Ulceration.Theulcerationisabreakintheepithelialcontinuityduetodestruction.ConnectiveTissueAlterationsInfammatoryInfiltration.Inchronicinflammatorylesionstheconnectivetissueisinfiltratedbylymphocytes,plasmacells,histocytes,andscatteredpolymorphonuclearleukocytes.Theinflammatoryinfiltratemaybehomogeneouslyspreadthroughouttheconnectivetissue,localizedinabroadbandclosetotheepithelium(asinlichenplanus),orperivascular(asindiscoidlupuserythematosusorsyphilis).Inacuteinflammatorylesions,theprimarycelloftheinfiltrateisthepolymorphonuclearleukocyte.Inulceratedareas,thesurfaceexudatecontainslargenumbersofleukocytes.Thepresenceofeosinophilleukocytesmaysuggestanallergicresponseoraparasiticinfestation,butthesecellsarealsocommonlyseeninhealingmacosallesions.Multinucleatedgiantcellsmaybepresentinaforeignbodyreaction,andspecifictypessuchasLanghans'cellsarehighlysuggestiveofatuberculouslesion.Hyperplasia.Hyperplasiaofconnectivetissueischaracterizedbyanincreaseddensityofcollagenfibers,asindiphenylhydantoin(Dilantin)reaction.CollagenDegeneration.Thisisanimportantconnectivetissuechange,characterizedbya"coagulation"orclumpingofcollagenbundlessothatthefibroustextureisabsent.Thisconditionisseeninradiationlesionsandlupuserythematosus.Vascularity.Thenumberofcapillariesandtheirengorgementwitherythrocytesmaybeincreased.MucousGlandAlterations.Obstructionofmucousglandsbyinflammationmayresultinacinardistentionandductaldilatation.VOCABULARYl.grossly肉眼地2.macroscopic肉眼的3.macule斑(点)4.papule丘疹5.plaque斑块，血小板6.vesicle小水疱7.bulla大疱8.pustule脓疱9.ulcer溃疡10.erosion糜烂11.nodule结节12.tumor肿瘤13.atrophic萎缩14.circumscribed环状的15.pinhead帽针头16.eruption疹17.punctatehemorrhages点状出血18.petechiae瘀斑19.thrombocytopenicpurpura血小板减少性紫斑20.melanindeposition黑色素沉着21.Addison'sdisease阿狄森病22.vascularmalformation血管畸形23.hereditorytelangiectasia遗传性毛细血管扩张症24.ovoid卵形的25.dermatosis皮肤病26.lacelike花边的27.annular环状的28.pebbled卵石的29.crack裂缝30.fissure沟纹31.leukoplakia白斑32.carcinoma癌33.discoidlupuserythematosus盘状红斑狼疮34.vesicalar疱的35.subepithelial上皮下的36.intraepithelial上皮内的37.epithelium上皮38.bleb疱，大疱39.bullous疱的40.pemphigus天疱疮41.pemphigoid类天疱疮42.erythemamultifomle多形红斑43.herpeticstomatitis疱疹性口炎44.drugeruption药疹45.purulent脓的46.pyostomatitis脓性口炎47.fbrin纤维48.polymorphonuclearleukocyte多形核白细胞49.infiltration浸润50.acuteinflammatorylesion急性炎性病损51.edge边缘52.ragged粗糙的53.tuberculosis结核54.indurated硬结的55.elongaged伸长的56.trauma创伤57.rupture裂58.stratumgerminativum生发层59.fibroma纤维瘤60.neoplasm新生物61.pyogenicum脓62.angiogranuloma血管颗粒瘤63.mandatory强迫性的64.criteria标准65.exoriat