Izinguquko zeselula ezibangelwa ukuvezwa kwe-UV ngokweqile
Ukukhanya kwelanga kunomthelela ojulile esikhumbeni esingabangela ukuguga ngaphambi kwesikhathi, umdlavuza wesikhumba, kanye nezinye izimo ezihlobene nezikhumba. Ukuboniswa kwama-ultraviolet (UV) ukukhanya kwama-akhawunti angu-90 amaphesenti azo zonke izimpawu zokulimala kesikhumba.
Amaqiniso Nge-UV Radiation
Ilanga liphuma emisebeni ye-UV esiyihlukanisa ibe yizigaba ngokusekelwe ku-longue of their relative (njengoba kulinganiswa yinanometer, noma nm):
- UV radiation (100 kuya ku-290 nm)
- Imibala ye-UVB (290 kuya ku-320 nm)
- Imisebe ye-UV (320 kuya ku-400 nm)
Imisebe ye-UVC inomkhawulo omfushane kakhulu futhi isondelene ngokuphelele ne-ozone ungqimba. Njengoba kunjalo, akuthinti ngempela isikhumba. Kodwa-ke, imisebe ye-UVC ingatholakala emithonjeni enjalo yokufakelwa njengezibani ze-mercury arc nezibani ze-germicidal.
Imisebe ye-UVB ithinta uhlaka olungaphandle lwesikhumba (i-epidermis) futhi iyimbangela enkulu yokushisa kwelanga. Kunamandla kakhulu phakathi kwamahora ka-10 ekuseni no-2 ntambama lapho ilanga likhanya kakhulu. Kubuye kube nzima nakakhulu ezinyangeni zasehlobo, kubalwa ngamaphesenti angama-70 omuntu ngamunye we-UVB. Ngenxa yokuthi i-UVB ayifinyeleleki, i-UVB ayitholi kalula ngilazi.
Imisebe ye-UVA, ngokuphambene, yayicatshangwa ukuthi inomphumela omncane esikhumbeni kuphela. Ucwaningo luye lwabonisa ukuthi u-UVA uyinhloko enkulu ekulimazeni kesikhumba. I-UVA ifinyelela ekujuleni kakhudlwana esikhunjeni ngokuqina okungagculiseki kakhulu nge-UVB.
Futhi, ngokungafani ne-UVB, u-UVA akahlungi ngilazi.
Imiphumela emibi ye-UVA ne-UVB
Zombili imisebe ye-UVA ne-UVB ingabangela ukulimala okuhlobene nezikhumba eziningi, kuhlanganise imibimbi, ukuphazamiseka okuhlobene nokuguga , umdlavuza wesikhumba kanye nokuzivikela okuthelelekile ekutheleleni. Nakuba singayiqondi ngokugcwele izindlela zalezi zinguquko, abanye bakholelwa ukuthi ukuwa kwe-collagen nokubunjwa kwama-radicals mahhala kungaphazamisa i-DNA ukulungiswa ezingeni lemangqamuzana.
Imisebe ye-UV iyaziwa ukwandisa inani le-moles ezingxenyeni ezivuliwe zelanga zomzimba. Ukwehliswa kwelanga ngokweqile kungaholela ekuthuthukiseni izilonda eziphambili ezibizwa nge-actinic keratoses. I-actinic keratoses ibhekwa njengesiqhwaga ngoba eyodwa ku-100 izokhula ibe yi- squamous cell carcinoma . Ama-actinic keratoses "ama-bumps" ngokuvamile alula ukuzizwa kunokuba abone futhi azovame ukuvela ebusweni, ezindlebeni nasemuva kwezandla.
Ukuvezwa kwe-UV kungabangela futhi ama- seborrheic keratoses , avela njengezilonda ezinjenge-wart "ezinamathele" esikhumbeni. Ngokungafani ne-actinic keratoses, i-seborrheic keratoses ayifuni umdlavuza.
I-Collagen Breakdown and Free Radicals
Imisebe ye-UV ingabangela i-collagen ukuba iphule ngokwezinga eliphakeme kunokuguga okuvamile . Lokhu kwenza lokhu ngokufaka ungqimba ophakathi wesikhumba (i-dermis), okubangela ukufakwa okungavamile kwe-elastin. Lapho lezi zinhlobo ze-elastin zibuthelwa, ama-enzyme akhiqizwa okuyinto engaqedi ukuphula i-collagen futhi idale okuthiwa "izibazi ze-solar." Ukuvezwa okuqhubekayo kuvinjelwa kuphela inqubo, okuholela ekuqhumeni okuqhubekayo nokugubha.
Umshini we-UV ungomunye wabadali abakhulu bama- radicals mahhala . Ama-radicals amahhala yi-molecule e-oxygen engazinzile ene-electron eyodwa kuphela esikhundleni se-two.
Ngenxa yokuthi ama-electrons atholakala ngezibili, i-molecule kufanele ihlasele i-electron yayo engekho eminye imamolekhamwana, okwenza ukwenziwa kwamakhansela kungalimaza amaseli ezingxenyeni zamangqamuzana. Ama-radicals wamahhala akhuliseli kuphela inani le-enzyme ephula i-collagen, angashintsha izinto eziphathekayo zofuzo ngendlela engabangela umdlavuza.
Imiphumela Yomzimba We-Immune
Umzimba unesimiso sokuvikela omzimba sokuzivikela okuhloswe ukuhlasela izifo kanye nokukhula okungavamile kwamaseli, kuhlanganise nomdlavuza. Lokhu kuvikelwa komzimba kuhlanganisa amangqamuzana egazi amhlophe abizwa ngokuthi i-T lymphocytes namaseli esikhumba abizwa ngamaseli e-Langerhans . Lapho isikhumba sibhekene nelanga eliningi, kukhishwa amakhemikhali athile acindezela lezi zinqamuzana ngokucindezela, okwehlisa impendulo yomzimba wonke.
Lena akuyona yodwa indlela lapho ukuvezwa ngokweqile kunganciphisa umkhuhlane womuntu. Into yokugcina yokuzivikela komzimba into okuthiwa i-apoptosis, inqubo "yokuzibulala" isisindo sokubulala amangqamuzana abonakalisiwe abangeke abe nomdlavuza. (Lesi esinye sezizathu zokuthi kungani uhlaziya emva kokushisa kwelanga.) Nakuba inqubo ingacaciswanga ngokugcwele, ukuvezwa kwe-UV ngokweqile kubonakala kuvimbela i-apoptosis, okuvumela amangqamuzana angenakuqhathaniswa ithuba lokuba yingozi.
Izinguquko Zesikhumba Ezibangelwa Ilanga
Ukuvezwa kwe-UV kubangelwa ukuqina nokwehlisa isikhumba esibizwa ngokuthi i-solar elastosis, okuholela ekugqibeni okunamandla nokudilika okuphuzi. Kungabangela nokuthi izindonga zemithambo yegazi zibe mncane, okuholela ekusikhenizeni okulula nokuyi-spider veining (telangiectasias) ebusweni.
Izinguquko ezivame kakhulu zokushisa kwelanga ezishintsha kakhulu ziyi-freckles (i-lentigo yelanga). I-freckle ibangelwa lapho amangqamuzana ekhanda lokukhiqiza i-pigment ( melanocytes ) ewonakele, okuholela ekwandiseni isici. Izimpande ezinkulu, eziyaziwa ngokuthi izindawo zama-age , zivame ukuvela emaceleni ezandla, esifubeni, emahlombe, ezandleni nasezindaweni ezingenhla. Ngenkathi amabala omdala avame ukubonakala kubantu asebekhulile, ahlobene nobudala njengoba igama labo libonisa kodwa umphumela wokulimala kwelanga.
Ukuvezwa kwe-UV kungabangela nokubonakala kwamabala amhlophe emilenzeni, izandla, kanye nezingalo njengoba ama-melanocytes ahlaselwa phansi ngokushiswa kwemisebe yelanga.
I-Cancer ne-Melanoma
Ikhono elangeni lokubangela umdlavuza liyaziwa kahle. Izinhlobo ezintathu ezinkulu zomdlavuza wesikhumba ziyi- melanoma , i- basal cell carcinoma , ne-squamous cell carcinoma.
I-Melanoma iyona ebulala kakhulu kunazo zonke njengoba isakazeka (metastasizes) kalula kakhulu kunabanye. I-basal cell carcinoma iyona evame kakhulu futhi ijwayele ukusakaza endaweni yangakini kunokuba isetshenziswe. I-squamous cell carcinoma yiyona eyesibili evamile futhi iyaziwa ukuthi i-metastasize, nakuba ingajwayelekile njenge-melanoma.
Kukholelwa ukuthi inani lokushisa kwelanga umuntu athola ngaphambi kokuba aneminyaka engama-20 yiyona nto ebangela ingozi ye-melanoma. Ngokuphambene nalokho, ingozi ye-basal cell carcinoma noma i-squamous cell carcinoma ihlobene kokubili uhlobo lomzimba lomuntu kanye nenani lokuchayeka kwempilo emisebeni ye-UV.
> Imithombo
- > Ratushny, V .; I-Gober, M .; Hick, R .; et al. "Kusuka ku-keratinocyte kuya emdlalweni: i-pathogenesis ne-modeling ye-squamous cell carcinoma." I-Journal of Investigation Clinic. Ngo-February 1, 2012; 122 (2): 464-472.
- > Narendhirakannan, R. noHannah, A. "Ukucindezeleka Oxidative kanye neKhansela Yesikhumba: Sibutsetelo." Ind J Clin Biochem. Ephreli 2013; 28 (2): 110-115.