皮膚的構(gòu)造與功能

皮膚的構(gòu)造與功能皮膚的構(gòu)造與功能第1頁LookatyourskinMorethanacoveringAvitalorgan,complexstructureDevelopfromthesametissuesasthebrain皮膚的構(gòu)造與功能第2頁SkinfactsSurfacearea:about2500cm2inanewbornbaby,18000cm2inanadult.About6-16%ofbodyweight:average3kginawoman,perhaps5kginaman.thickness:variesonsites.thinnestontheeyelidsandthickestonthepalmsandthesoles.皮膚的構(gòu)造與功能第3頁Threelayers:

epidermis,dermis,subcutaneousfat皮膚的構(gòu)造與功能第4頁EpidermisThickness:35-50m,only20maroundeye,thickeronthepalmandsole(mm)oxygenandnutrientsfromthedermisTranslucentBasementmembraneReteridges皮膚的構(gòu)造與功能第5頁Epidermis-2AllkeratinocytesoriginatefrombasallayerMoveupward,changeshapeandlossnucleus,produceskinprotein(keratin)andfat(sphigolipid,ceramide)Corneocytes:deadResisttoinjurykeepwater皮膚的構(gòu)造與功能第6頁Epidermis-2Desquamation(squames)Renewcycle:about30daysPsoriasis:4-7timesfasterSpeedup:sunburn,peelaging皮膚的構(gòu)造與功能第7頁Epidermis-3Amodelof“bricksandmortar”Corneocytes,desmosomes,naturalfatupto15%ofthestratumcorneumconsistsofwater.TEWL(transepidermalwaterloss)皮膚的構(gòu)造與功能第8頁Dermis3000mthick,keepresilienceandsuppleContainbloodvessels,nerves,hairrootsandsweatglandsFibroblastsmakecollagenandelastinGroundsubstance:glycoprotein(hyaluronicacid,chrondroitinsulfate),maintainwater皮膚的構(gòu)造與功能第9頁Dermis-2Collagen:75%Elasticfibers:Elastin,5%StretchmarksWoundrepairAcrosslines,deep,largeGranulationtissueHypertrophicscarKeloid

皮膚的構(gòu)造與功能第10頁SubcutaneousfatlayerAdipocytes,largervesselsandnervesDepthdiffersfromsiteandindividualCushing,conservebodyheatstorefat:women(buttocksandthighs),men(abdominalwall)cellulite皮膚的構(gòu)造與功能第11頁SebaceousglandsPartofhairfolliclesineverypartexceptpalmandsoleSebum:pH=4.2-5.6,protectskinandlubricatehairshaftMixtureofsebumandsweat:naturaloil-in-wateremulsion,killsomefungiInfluencebymalehormonemostsensitiveatpubertyonfaceandtrunk皮膚的構(gòu)造與功能第12頁EccrineglandsEmptydirectlyontotheskinineverypartexceptlipsandglanspenisProducesweat:mixtureofwaterandsaltsRegulatethebodytemperatureRemovewaste皮膚的構(gòu)造與功能第13頁ApocrineglandsInaxillaryandgenitalarea,breastDecapitationsecretionDependentonsexhormoneGermsgrowinmoistareaproducebodyodor皮膚的構(gòu)造與功能第14頁HairsVellushairs:mostskin,attachedtotinymusclesinthedermis,“goosebumps”Terminalhairs:scalp,eyelids,eyebrows,Beard,chest,armandleg:duetomalehormoneCuticle,cortex,medulla皮膚的構(gòu)造與功能第15頁BloodvesselsSupplytheskinandappendagesRegulatebodytemperatureSympatheticnervemakeitconstriction;parasym.nerve,dilatation.皮膚的構(gòu)造與功能第16頁NervesAutonomicnerves:vessels,sweatglands,smoothmusclesSensorynervesSubepidermalplexusMerckelplexus皮膚的構(gòu)造與功能第17頁Functionsoftheepidermisprotectingthebodyfromtheenvironment,particularlythesunpreventingexcessivewaterlossfromthebodyprotectingthebodyfrominfection.皮膚的構(gòu)造與功能第18頁Functionsoftheepidermis-1ultravioletradiationcreatefreeradicalsprotectingthenucleiofthecellsintheepidermisandthecollagenofthedermisPartisreflectedbythestratumcorneumattheskinsurfacepartisabsorbedbythemelaninintheepidermalcellssomeisscatteredwithintheskin皮膚的構(gòu)造與功能第19頁Functionsoftheepidermis-2Water:70-75%oftheweightofthebasallayer,butonly10-15%ofthestratumcorneum.Ifbelow10%,itbecomesdry,lessflexibleandpronetodamage,breakdownandinfection.Theepidermisasawholeisabout35

mthickwhendry,swellto48

monfullhydration.皮膚的構(gòu)造與功能第20頁Functionsoftheepidermis-3HydrationcomponentsofStratumcomponent1.Keratin2.acornifiedenvelopeofcorneocytes3.LipidsLinoleicacid(diet),ceramides4.naturalmoisturisingfactors(NMF)Aminoacids(40%),pyrrolidonecarboxylicacid(12%),lacticacid(12%),urea(8%),salts(18%),unidetifiedcompounds(10%)5.desmosomes6.enzymes皮膚的構(gòu)造與功能第21頁Functionsofthee