皮肤的构造与功能

皮肤的构造与功能皮肤的构造与功能第1页LookatyourskinMorethanacoveringAvitalorgan,complexstructureDevelopfromthesametissuesasthebrain皮肤的构造与功能第2页SkinfactsSurfacearea:about2500cm²inanewbornbaby,18000cm²inanadult.About6-16%ofbodyweight:average3kginawoman,perhaps5kginaman.thickness:variesonsites.thinnestontheeyelidsandthickestonthepalmsandthesoles.皮肤的构造与功能第3页Threelayers:

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

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

mthickwhendry,swellto48

monfullhydration.皮肤的构造与功能第20页Functionsoftheepidermis-3HydrationcomponentsofStratumcomponent1.Keratin2.acornifiedenvelopeofcorneocytes3.LipidsLinoleicacid(diet),ceramides4.naturalmoisturisingfactors(NMF)Aminoacids(40%),pyrrolidonecarboxylicacid(12%),lacticacid(12%),urea(8%),salts(18%),unidetifiedcompounds(10%)5.desmosomes6.enzymes皮肤的构造与功能第21页Functionsofthee