I- epidermis ingxenyeni engaphandle kwesikhumba futhi yenziwe ngezigaba ezinhlanu. I-stratum corneum yiyona engaphandle kwalezo zigaba ezinhlanu futhi ngokuyinhloko iyasebenza njengesithiyo.
Ngaphambi kwawo-1970, i-stratum corneum yayicatshangelwa ukuthi iyisimbiso sezinto eziphilayo, njengeplastiki encane evikela isikhumba esisebenzayo, esicansi. Emashumini ambalwa ambalwa adlule, ososayensi bathole ukuthi umsebenzi we-biological and chemical of stratum corneum empeleni unzima kakhulu futhi unzima.
Ukuqonda isakhiwo kanye nokusebenza kwe-stratum corneum kubalulekile ngoba kuyisihluthulelo sokuba nomzimba onempilo futhi okhangayo. Le mifanekiso izokuthatha ngokusebenzisa izingxenye ezibalulekile ze-stratum corneum.
I-Corneocyte
I-stratum corneum inesakhiwo sakhiwo, "izitini" kulo mfanekiso kukhona amaprotheni ezinkimbinkimbi okuthiwa i-corneocytes (bheka umfanekiso). I-corneocyte yenziwe ngezintambo ezincane ze-keratin ku-matrix ehleliwe. I-keratin ingabamba amanzi amaningi phakathi kwezingubo / izintambo. I-stratum corneum iqukethe izingxenye ezingaba ngu-12 kuya kwezingu-16 ze-corneocytes, futhi i-corneocyte ngayinye ine-thickness ye-micrometer eyi-1, kuye ngokuthi izici ezilandelayo: yobudala, indawo ye-anatomical, nokuvezwa kweminye imisebe ye-UV .
Ama-Lamellar Bodies
Imizimba yama-lamellar yakhiwa kuma-keratinocytes we- stratum spinosum ne-stratum granulosum. Lapho i-keratinocyte ikhula e-stratum corneum, ama-enzyme adiliza imvilophu yangaphandle yamagumbi amhlophe, ekhulula izinhlobo ze-lipids ezibizwa ngokuthi amahhala ama-acids nama-ceramide.
I-Lipids ye-Intercellular
Ama-acids amafutha amahhala nama-ceramide akhululwa emzimbeni we-lamellar afakwe ndawonye ku-stratum corneum ukuze enze uhlaka oluqhubekayo lwe-lipids. Ngenxa yokuthi kunezinhlobo ezimbili ze-lipids, lo ungqimba ubizwa ngokuthi i-lamellar lipid bilayer. I-lipid bilayer idlala indima ebalulekile ekugcineni izinto ezivimbela isikhumba futhi iyafana "nesitshalo" esifanekisweni sezitini nezomdaka.
Invilophu ekhonjiwe
I-corneocyte ngayinye ikhiqizwe igobolondo leprotheyini elibizwa ngokuthi i-envelope yeselula. Imvilophu yeselula yakhiwe ngokuyinhloko ngamaprotheni amabili, i-loricrin ne-involucrin. Lawa maprotheni aqukethe izixhumanisi eziningi phakathi komunye nomunye, okwenza imvilophu yeseli ibe isakhiwo esingenasisindo se-corneocyte. Lezi zinhlobo ezimbili ze-envelope ze-cell zichazwa ngokuthi "ziqinile" futhi "zibuthakathaka," ngokususelwa ekusebenzisaneni kwe-lamellar lipid bilayer nevulophu yeselula.
Imvelo ye-Envelope Lipids
Ifakwe emvilophini yesisindo ungqimba lwe-ceramide lipids eliphikisa amanzi. Ngenxa yokuthi i-lamellar lipid bilayer iphinde iphethe amanzi, ama-molecule ayenziwa phakathi kwe-envelope lipids kanye ne-lipid bilayer. Lokhu kusiza ukugcina ibhalansi yamanzi ku-stratum corneum ngokubamba ama-molecule wamanzi, esikhundleni sokubavumela ukuba bangene emigqeni engezansi ye-epidermis.
I-Corneodesmosomes
I "rivets" ebambe i-corneocytes ndawonye yizinhlaka ezikhethekile zeprotheni ezibizwa nge-corneodesmosomes. Lezi zakhiwo nazo ziyingxenye "yodaka" ekufanekiseni "ngesitini nenyama". I-Corneodesmosomes yizakhiwo ezinkulu okumelwe zihlaziywe isikhumba ukuba zichithe inqubo ebizwa ngokuthi i-desquamation.
I-Factor Moisturizing Factor (i-NMF)
Isisindo somswakama wemvelo (i-NMF) iqoqo lamakhemikhali ahlanganiswe ngamanzi atholakala kuphela kwi-stratum corneum. Lezi zinhlanganisela zihlanganisa cishe amaphesenti angu-20 kuya ku-30 wesisindo esomile se-corneocyte. Izingxenye ze-NMF zithatha amanzi emkhathini bese zihlangana ngokuqukethwe kwawo kwamanzi, okuvumela izingxenye zangaphandle ze-stratum corneum ukuba zihlale zixhumane naphezu kokuvezwa kwezakhi. Ngenxa yokuthi izingxenye ze-NMF zingencibilika kwamanzi, zivele zivele kalula kumaseli axhumana nomanzi-yingakho ukuxhumana ngokuphindaphindiwe ngamanzi empeleni kwenza isikhumba siphume. Uhlaka lwe-lipid oluzungeze i-corneocyte lusiza uphawu lwe-corneocyte ukuvimbela ukulahlekelwa kwe-NMF.
Inqubo yokuqothula
Inqubo yokuqhathaniswa noma ukukhishwa kwe-stratum corneum empeleni iyinkimbinkimbi kakhulu futhi izingxenye zalolu hlelo ziqondwa ngokugcwele. Kuyaziwa ukuthi ama-enzyme amaningana adiliza ama-corneodesmosomes ngendlela ethile, kodwa isimo sangempela salezi zinkimbinkimbi noma ukuthi zenziwa kanjani ukuze kuqalwe inqubo yokukhipha imfuyo engaziwa. Amanzi kanye ne- pH badlale indima ebalulekile emsebenzini walezi zinyimba.
> Imithombo:
> van Smeden J, Hoppel L, van der Heijden R, Hankemeier T, Vreeken RJ, Bouwstra JA. Ukuhlaziywa kwe-LC / MS kwe-stratum corneum lipids: ukuprofetha kwe-ceramide nokutholakala. I-Lip Lip Res . 2011 Jun; 52 (6): 1211-1221.
> Walters RM, Mao G, Gunn ET, Hornby S. Ukuhlanzwa kwemvelo okuhlonipha ubuqotho besikhumba. I-Dermatol Res Pract . 2012; 2012: 495917.
> Johnson, AW. (2015). I-cosmeceuticals: Umsebenzi kanye ne-Skin Barrier. Izinqubo ze-Cosmetic Dermatology - Cosmeceuticals . Ed. U-Zoe Diana Draelos. Elsevier, 11-17.
> Verdier-Sévrain S, i-Bonté F. I-hydration ye-Skin: ukubuyekezwa kwindlela zayo zamangqamuzana. J Cosmet Dermatol. 2007 Jun; 6 (2): 75-82.