（瘢痕疙瘩）课件

ChaptertwoRepair SuMin 苏敏 Definition Repairistheprocessbywhichlostordestroyedcellsarereplacedbyvitalcells regeneration Section1Regeneration Definition Thesurvivinghealthycellsnearbydamageproliferateandmoveforrepair 1 Type 1 Completeregeneration Thenewtissueisthesamewiththelossinstructureandfaction Commonlyinphysiologicalregeneration Conditions theabilityofregenerationofparenchymaltissueisstrong damageareaissmallandthestromalframeworkoftheinjuredtissueispreservativewell 2 Incompleteregeneration granulationtissue stromalorfillerelements proliferatetofilldefect replacementbyscar Commonlyinpathologicalregeneration Conditions theabilityofregenerationofparenchymaltissueisweak damageareaisextensiveandthestromalframeworkoftheinjuredtissueisnotpreservativewell 2 TheregenerativecapacitytypesofcellsLabilecells normallyacontinuousprocessofactivereplacementisoccurring Thechancesofrestorationbyregenerationareexcellent Examples thecoveringepithelium thebonemarrowcellsandthelymphoidcells 2 Stablecells Althoughnormallythereplacementrequirementsareminimal theyhavenotlostthecapacitytoproliferateinresponsetostimulation Chancesofregenerationremain Examples adenocytesofparenchymalviscera includingendocrine allstromalelements 3 Permanentcells Normallyareunabletomultiplyafterthegrowthearlyinlife Examples nervecells striatedandcardiacmusclecells smoothmusclecells Butperipheralnervehasretainedthecapacityforregenerationwithdamage 3 Regenerativeprocessoftissues 1 Epithelialtissue Coveringepithelia Marginalproliferationmayresultinaperfectrestoration Glandularepithelia Althoughinmanyinstancetheadenocytesoftheorgancandivide theend resultisoftendependentuponlocalfactors inparticulartheintegrityofthebasementmembranesandreticulinscaffoldthatarenecessaryfortheregeneratingcellstobesogroupedastoreformnormalfunctionalandanatomicalglandulartissue 2 Fibroustissue Fibrocytes Primitivecells situatedaroundcapillariesandlooseconnectivetissuesFibroblastsSecretionofgroundsubstanceincludingadhesiveGlycoproteins Fibronectins SecretionofTropocollagen veryfinefibrilsdetectedbyEM condensationtoformReticulinfibres finefibrilsstainedbysilver condensationtoformCollagenfibres Bondingandweaving FibrocytesScartissue 3 Bloodvessel Capillaries regenerationbysproutform Theinitialstepintheingrowthsofcapillariesinvolvestheenzymaticdissolutionofthebasementmembraneofexistingcapillaries Thisisfollowedbyproliferationofendothelialcellsandmigrationofasolidsproutorbudofendothelialcellswhichdifferentiate undergocanalizationandbyanastomosiswiththeirneighboursformaseriesofvasculararcades Atfirstthenewlyformedvesselsshowgapsbetweentheendothelialcells apoorlyformedbasementmembrane andlongpseudopodiaoftheendothelialcellswhichreachoutintotheconnectivetissuespaces Soonfurtherdifferentiationmayoccurtoadapttoneedsoffunction Somevesselsacquireamuscularcoatandbecomearterioles whilstothersenlargetoformthin walledvenules Bigbloodvessels Endothelialcellscouldbeperfectrestorationbycompleteregeneration butcuttingsmoothmuscleareconnectedbyscar 4 Fracturedlongbone Haemorrhageandinflammation Organizationandproliferationofperiostealcells WoverboneandcartilageCalcificationofcartilageandosteoid Conversiontolamellarbone Remodelling Section2Repairbyconnectivetissue Proliferationoffibroblastsandcapillarybudsandthesubsequentlayingdownofcollagentoproduceascaristheusualconsequenceofmosttissuedamage 1 Definition Thisisyoungconnectivetissue whichisrichinyoungfibroblastsandcapillaries2 Morphology 1 grossfeature pink soft moist andgranularappearance 2 LM fibroblasts newcapillaries capillarysproutandmigratetowardthewound Thenewcapillaryendothelialcellsareswollenandcapillarytubesarenarrow Thesenewvesselshaveleakyinterendotheialjunctions Allowthepassageofproteinsandredcellsintotheextravascularspace thus newgranulationtissueisoftenedematous inflammatorycells Granulationtissue 3 Consequences Granulationtissue fibroblasts Newcapillaries Inflammatorycells collagenfibres vascularitydiminishing gradually fibrocytes Bondingandweaving disappear disappear Scartissue 4 Function 1 anti infectionandprotectingthesurfaceofwound 2 organization granulationtissuereplacenecrotictissue bloodclot andforeignbodies 3 encapsulation 4 fillingwoundorlossoftissue Section3Woundhealing 1 Definition Referstothebody sreplacementofdestroyedtissuebylivingtissue2 Stagesinhealingofwound 1 Escapeofbloodandexudates 2 Acuteinflammation 3 Contractionofthewound Thecausesofcontractionarenotknownbutpossiblemechanismsare Shrinkageofscabinsuperficialwounds Contractionpropertiesofgranulationtissueattributabletocontractionofmyofibroblastsortissuere modeling 4 Proliferationandmigrationoffibroblastsandendothelialcells 5 Progressiveincreaseinmaturecollagenfibresduringthesecondweekformingascar 6 Lossvascularityandshrinkageofthescar 3 Typeofwoundhealing 1 HealingbyfistintentionAcleanwoundwithaminimumofspacebetweenthemargins 2 HealingbysecondintentionHealingbysecondintentiondiffersfromhealingbyfirstintentionin Greatertissueloss Moreinflammatoryexudatesandnecroticmaterialtoremove Moregranulationtissuethereforeabiggerscar Theorderlyphasesofwoundhealing Woundcontractionnecessary Slowerprocess Increasedliabilitytoinfection 3 Healingunderscab Keloid 瘢痕疙瘩 4 Factorsinfluencingwoundhealing 1 Localfactorsadverselyaffectinghealing Typeofwoundingagent blunt crushing tearingetc Infection Foreignbodiesinwound Poorbloodsupply Excessivemovement Poorappositionofmargins e g largehaematomaformation Poorwoundcontractionduetotissuetethering Infiltrationbytumor Previousirradiation 2 Generalfactorsadverselyaffectinghealing Age PoornutritionDeficiencyofproteinLackofVitaminCresultsinabno