医学英语 皮肤系统Skin#

TheskinandSkinRegenerativeMedicine再生医学LujunYangBurnsandPlasticsuregeryCenterforTranslationalmedicine2ndHospitalofShantouUniversityKayiName?Agingskinskin

thelargestorganinthebodyprotectsenseregulatetemperatureProductionofVitaminDClininiansDermatology-----dermatologistPlasticandestheticsurgery------plasticsurgeonKeratinocytefibroblastOBJECTIVEMaster

skinstructureandfunction

epidermis-----keratinization角化作用:proliferation增殖/differentiation分化AcquaitanceAnomalies异常现象

ofskin----commonskindiseases

AdvanceSkinregenerativemedicine皮肤再生医学INTRODUCTIONepidermisdermishypodermisDermis真皮Papillarylayer乳头层+Reticularlayer网状层第二节真皮epidermishypodermisdermisskindermis真皮papillarylayer乳头层reticularlayer网织层appendages附属器hair毛sebaceousgland皮脂腺sweatgland汗腺THESTRUCTUREOFSKINepidermis表皮stratumcorneum角质层stratumlucidum(透明层)stratumgranulosum颗粒层stratumspinosum棘层stratumbasale基底层nail指(趾)甲EPIDERMIS主要细胞组成keratinocyte(角质形成细胞

)non-keratinocyte(非角质形成细胞)differentiationstratumcorneum角质层

stratumgranulosum颗粒层stratumlucidum(透明层)

stratificationstratumbasale基底层stratumspinosum棘层（一）EpidermalstratificationanddifferentiationPSORIASIS银屑病redandwhitehuesofscalypatchesappearingonthetopfirstlayeroftheepidermis(skin).Langerhanscell(郞格汉斯细胞)Langerhanscellsaredendriticcells(antigen-presentingimmunecells)oftheskinandmucosa,andcontainlargegranulescalledBirbeckgranules.Theyarepresentinalllayersoftheepidermis,butaremostprominentinthestratumspinosum.Inskin

infections,thelocalLangerhanscellstakeupandprocessmicrobial

antigenstobecomefullyfunctionalantigen-presentingcells.Langerhanscellsderivefromthecellulardifferentiationofmonocyteswiththemarker"Gr-1"(alsoknownas"Ly-6G/Ly-6C").Thisdifferentiationrequiresstimulationbycolonystimulatingfactor(CSF)-1.6Theyaresimilarinmorphologyandfunctiontomacrophages.Albinoslackanenzymecalledtyrosinase络氨酸酶.Tyrosinaseisrequiredformelanocytestoproducemelaninfromtheaminoacid

tyrosine

melanocyte(黑素细胞)Melanocytesaremelanin-producingcellslocatedinthebottomlayer(thestratumbasale)oftheskin‘sepidermis,themiddlelayeroftheeye(theuvea),theinnerear,meninges,Melaninisapigment色素

thatisresponsibleprimarilyforthecolorofskin.Nodifferenceinmelanocytenumberbetweenspecies.Thedistributionandtyrosinaseactivity!VitiligoMelanoma(黑色素瘤):4%ofalldiagnosedskincancers,melanomabeginsinthemelanocytes,cellswithintheepidermisthatgiveskinitscolor.Melanomahasbeencoined“themostlethalformofskincancer”becauseitcanrapidlyspreadtothelymphsystemandinternalorgans.Withearlydetectionandpropertreatment,thecurerateformelanomaisabout95%.Onceitsspreads,theprognosisispoor.Melanomamostoftendevelopsinapre-existingmoleorlookslikeanewmole,whichiswhyitisimportantforpeopletoknowwhattheirmoleslooklikeandbeabletodetectchangestoexistingmolesandspotnewmoles.

TheHair

SebaceousGlands

皮脂腺SweatGlands

TheNails

TheAccessaryStructuresoftheSkinAcnevulgaris寻常痤疮普通粉刺

(orcysticacne)isacommondisease,characterizedbyareasofskinwithscaly鳞状的

redskin,blackheads黑头粉刺

andwhiteheads,pinheads针头,pimples丘疹,nodules小瘤

andpossiblyscarring结疤.Acneaffectsmostlyskinwiththedenset密集

populationofsebaceousfollicles皮脂腺;theseareasincludetheface,theupperpartofthechest,andtheback.Severeacneisinflammatory炎症性的,butacnecanalsomanifest显现

innoninflammatoryforms.2Thelesions损伤

arecausedbychangesinpilosebaceous毛囊皮脂腺

units,skinstructuresconsistingofahairfollicleanditsassociatedsebaceousgland,changesthatrequireandrogen雄性激素

stimulation.Acneoccursmostcommonlyduringadolescence,andoftencontinuesintoadulthood.Inadolescence,acneisusuallycausedbyanincreaseintestosterone睾丸素,whichpeopleofbothgenders性别

accrueduringpuberty青春期.AlopeciaTotalis(全頭脱毛症）Alopeciameanslossofhairfromtheheadorbody.baldness,Hemidesmosomes(HD)areverysmallstud-orrivet-likestructuresontheinnerbasalsurfaceofkeratinocytesintheepidermisofskin.Theyaresimilarinformtodesmosomeswhenvisualizedbyelectronmicroscopy.Whiledesmosomeslinktwocellstogether,hemidesmosomesattachonecelltotheextracellularmatrix.Desmosomes细胞桥粒

aremolecularcomplexesofcelladhesion黏着蛋白

proteinsandlinkingproteinsthatattachthecellsurfaceadhesionproteinstointracellularkeratin

角蛋白cytoskeletal细胞支架细胞

filaments细丝.Thecelladhesionproteinsofthedesmosome,desmoglein桥粒芯蛋白

anddesmocollin桥粒胶蛋白,aremembersofthecadherin钙粘蛋白

familyofcelladhesionmolecules.Theyaretransmembraneproteinsthatbridgethespacebetweenadjacentepithelialcellsbywayofhomophilicbindingoftheirextracellulardomainstootherdesmosomalcadherinsontheadjacentcell.Bothhavefiveextracellulardomains,andhavecalcium-bindingmotifs.Age-associatedskinchangesincludethinning,skinlaxity松弛,fragility脆弱,andwrinkles皱纹.Sun-exposedareasdemonstrateadditionalagingchanges,includingdyspigmentation,prematurewrinkling,telangiectasia,andactinicelastosis.UVA400–315nmUVB315–280nmThesun

emitsultravioletradiationintheUVA,UVB,andUVCbands.TheEarth'sozonelayer

blocks97–99%ofthisUVradiationfrompenetratingthroughtheatmosphere.OftheultravioletradiationthatreachestheEarth'ssurface,98.7%isUVAPhotoaging光老化UVandmolecularandgeneticchangesUVBrayisconsideredasaprimarymutagenthatcanonlypenetratethroughtheepidermaloroutermostlayeroftheskin,resultinginDNAmutations.Theepidermallayerdoesnotcontainanybloodvesselsornerveendingsbutmelanocytesandbasalcellsareembeddedinthislayer.UponexposuretoUVBrays,melanocyteswillproducemelanin,apigmentthatgivestheskinitscolortone.However,UVBwillcausetheformationoffrecklesanddarkspots,bothofwhicharesymptomsofphotoaging.WithconstantexposuretoUVBrays,signsofphotoagingmightappearandprecancerouslesionsorskincancermaydevelop.UVAraysareabletopenetratedeeperintotheskinascomparedtoUVBrays.Hence,inadditiontotheepidermallayer,thedermallayerwillalsobedamaged.Thedermisisthesecondmajorlayeroftheskinanditcomprisescollagen,elastin,andextrafibrillarmatrixwhichprovidesstructuralsupporttotheskin.However,withconstantUVAexposure,thesizeofthedermislayerwillbereduced,therebycausingtheepidermistostartdroopingoffthebody.Duetothepresenceofbloodvesselsinthedermis,UVArayscouldleadtodilatedorbrokenbloodvesselsmostcommonlyvisibleonthenoseandcheeks.Photoaging:telangiectasia,pigmentationLaserandPhotonskintreatmentSunscreenSPF:ratiooftheminimalerythemadose(MED)ofsunscreen-protectedskinovertheMEDofunprotectedskin.CurrentlyavailableproductsofferexcellentprotectionfromUVBa