The Integumentary System医疗专题知识

Chapter5

TheIntegumentarySystemSkinanditsaccessorystructuresstructurefunctiongrowthandrepair1第1页GeneralAnatomyAlargeorgancomposedofall4tissuetypes22squarefeet1-2mmthickWeight10lbs.2第2页Overview3MajorlayersofskinEpidermisisepithelialtissueonlyDermisislayerofconnectivetissue,nerve&muscleHypodermis(subcutaneous)islayerofadipose&areolartissues3第3页OverviewofEpidermisStratifiedsquamousepitheliumContainsnobloodvessels4typesofcells5distinctstrata(layers)ofcells4第4页CelltypesoftheEpidermisKeratinocytes--90%producekeratinMelanocytes-----8%producesmelaninpigmentmelanintransferredtoothercellswithlongcellprocessesLangerhancellsfrombonemarrowprovideimmunityMerkelcellsindeepestlayerformtouchreceptorwithsensoryneuron5第5页Layers(Strata)oftheEpidermisStratumcorneumStratumlucidumStratumgranulosumStratumspinosumStratumbasale6第6页StratumBasaleDeepestsinglelayerofcellsCombinationofmerkelcells,melanocytes,keratinocytes&stemcellsthatdividerepeatedlyCellsattachedtoeachother&tobasementmembranebydesmosomes&hemidesmosomes7第7页StratumSpinosum8to10celllayersheldtogetherbydesmosomesDuringslidepreparation,cellsshrinkandlookspinyMelanintakeninbyphagocytosisfromnearbymelanocytes8第8页StratumGranulosum3-5layersofflatdyingcellsShownucleardegenerationContaindark-stainingkeratohyalingranulesContainlamellargranulesthatreleaselipidthatrepelswater9第9页StratumLucidum

Seeninthickskinonpalms&solesoffeetThreetofivelayersofclear,flat,deadcellsContainsprecursorofkeratin10第10页StratumCorneum25to30layersofflatdeadcellsfilledwithkeratinandsurroundedbylipidsContinuouslyshedBarriertolight,heat,water,chemicals&bacteriaFrictionstimulatescallusformation11第11页Keratinization&EpidermalGrowthStemcellsdividetoproducekeratinocytesAskeratinocytesarepusheduptowardsthesurface,theyfillwithkeratin4weekjourneyunlessouterlayersremovedinabrasionHormoneEGF(epidermalgrowthfactor)canspeedupprocessPsoriasis=chronicskindisordercellsshedin7to10daysasflakysilveryscalesabnormalkeratinproduced12第12页SkinGraftsNewskincannotregenerateifstratumbasaleanditsstemcellsaredestroyedSkingraftiscoveringofwoundwithpieceofhealthyskinautograftfromselfisograftfromtwinautologousskintransplantationofpatientsskingrowninculture13第13页DermisConnectivetissuelayercomposedofcollagen&elasticfibers,fibroblasts,macrophages&fatcellsContainshairfollicles,glands,nerves&bloodvesselsMajorregionsofdermispapillaryregionreticularregion14第14页PapillaryRegionTop20%ofdermisComposedoflooseCT&elasticfibersFingerlikeprojectionscalleddermalpapillaeFunctionsanchorsepidermistodermiscontainscapillariesthatfeedepidermiscontainsMeissner’scorpuscles(touch)&freenerveendings(painandtemperature)15第15页

ReticularRegionDenseirregularconnectivetissueContainsinterlacingcollagenandelasticfibersPackedwithoilglands,sweatglandducts,fat&hairfolliclesProvidesstrength,extensibility&elasticitytoskinstretchmarksaredermaltearsfromextremestretchingEpidermalridgesforminfetusasepidermisconformstodermalpapillaefingerprintsareleftbysweatglandsopenonridgesincreasegripofhand16第16页SkinColorPigments(1)Melaninproducedinepidermisbymelanocytessamenumberofmelanocytesineveryone,butdifferingamountsofpigmentproducedresultsvaryfromyellowtotantoblackcolormelanocytesconverttyrosinetomelaninUVinsunlightincreasesmelaninproductionClinicalobservationsfrecklesorliverspots=melanocytesinapatchalbinism=inheritedlackoftyrosinase;nopigmentvitiligo=autoimmunelossofmelanocytesinareasoftheskinproduceswhitepatches17第17页SkinColorPigments(2)Caroteneindermisyellow-orangepigment(precursorofvitaminA)foundinstratumcorneum&dermisHemoglobinred,oxygen-carryingpigmentinbloodcellsifotherpigmentsarenotpresent,epidermisistranslucentsopinknesswillbeevident18第18页AccessoryStructuresofSkin

EpidermalderivativesCellssinkinwardduringdevelopmenttoform:hairoilglandssweatglandsnails19第19页

StructureofHairShaft--visiblemedulla,cortex&cuticleRoot--belowthesurfaceFolliclesurroundsroot20第20页HairRelatedStructuresArrectorpilismoothmuscleindermiscontractswithcoldorfear.formsgoosebumpsashairispulledverticallyHairrootplexusdetecthairmovement21第21页HairColorResultofmelaninproducedinmelanocytesinhairbulbDarkhaircontainstruemelaninBlondandredhaircontainmelaninwithironandsulfuraddedGrayinghairisresultofdeclineinmelaninproductionWhitehairhasairbubblesinthemedullaryshaft22第22页Functionsof

HairPreventsheatlossDecreasessunburnEyelasheshelpprotecteyesTouchreceptors(hairrootplexus)senseslighttouch23第23页GlandsoftheSkinSpecializedexocrineglandsfoundindermisSebaceous(oil)glandsSudiferous(sweat)glandsCeruminous(wax)glandsMammary(milk)glands24第24页Sebaceous(oil)glandsSecretoryportioninthedermisMostopenontohairshaftsSebumcombinationofcholesterol,proteins,fats&saltskeepshairandskinfromsoft&pliableinhibitsgrowthofbacteria&fungi(ringworm)Acnebacterialinflammationofglandssecretionsstimulatedbyhormonesatpuberty25第25页

Sudoriferous(sweat)glandsEccrine(sweat)glandsmostareasofskinsecretoryportionindermiswithducttosurfaceregulatebodytemperaturewithperspirationApocrine(sweat)glandsarmpitandpubicregionsecretoryportionindermiswithductthatopensontohairfolliclesecretionsmoreviscousfunctionafterpuberty,“coldsweat”26第26页

CeruminousglandsModifiedsweatglandsproducewaxysecretioninearcanalCerumincontainssecretionsofoilandwaxglandsHelpsformbarrierforentranceofforeignbodiesImpactedcerumenmayreducehearing27第27页StructureofNailsTightlypackedkeratinizedcellsNailbodyvisibleportionpinkduetounderlyingcapillariesfreeedgeappearswhiteNailrootburiedunderskinlayerslunulaiswhiteduetothickenedstratumbasaleEponychium(cuticle)stratumcorneumlayer28第28页NailGrowthNailmatrixbelownailrootproducesgrowthCellstransformedintotightlypackedkeratinizedcells1mmperweek29第29页TypesofSkinThinskincoversmostofbodythinepidermis(.1to.15mm.)thatlacksstratumlucidumlacksepidermalridges,hasfewersweatglandsandsensoryreceptorsThickskinonlyonpalmsandsolesthickepidermis(.6to4.5mm.)withdistinctstratumlucidum&thickstratumcorneumlackshairfolliclesandsebaceousglands30第30页GeneralFunctionsoftheSkinRegulationofbodytemperatureProtectionasphysicalbarrierSensoryreceptorsExcretionandabsorptionSynthesisofvitamin31第31页SkinCancer1millioncasesdiagnosedperyear3commonformsofskincan