Iintsholongwane zeeNguqulelo ezibangelwa ukuboniswa kwe-UV excessively
Ukukhanya kwelanga kunempembelelo enkulu kwesikhumba esinokubangela ukuguga kwangaphambili, umdlavuza wesikhumba kunye neminye imiba ehlobene nekhumba. Ukuboniswa kwi-akhawunti ye-ultraviolet (UV) ukukhanya malunga neepesenti ezingama-90 yazo zonke iimpawu zengozi yesikhumba.
Amaqiniso Ngomlilo we-UV
Ilanga liphuma emisebeni ye-UV esiwahlula kwiindidi ngokusekelwe kwisilinganiselo sobude bayo (njengoko kulinganiswa ngunometer, okanye nm):
- UV radiation (100 ukuya ku-290 nm)
- UVB emisebeni (290 ukuya kuma-320 nm)
- I-radiation UVA (320 ukuya ku-400 nm)
I-UVC imisebe inomlinganiselo omfutshane kakhulu kwaye iphantse igxininiswe ngumgca we-ozone. Ngaloo ndlela, ayichaphazeli nangoko ulusu. Nangona kunjalo, umbane we-UVC unokufumaneka kwizinto ezinjalo ezifana nezibane ze-mercury kunye nezibane ze-germicidal.
Ukukhanya kwe-UVB kuphazamisa umgca wecala (i-epidermis) kwaye iyona nto ibangela ukushona kwelanga. Kunzima kakhulu phakathi kweeyure ezili-10 ukuya kweye-2 ntambama xa ilanga likhanya kakhulu. Kwakhona kunzima kakhulu kwiinyanga zasehlotyeni, kubalwa malunga neepesenti ezingama-70 zomntu onobungozi be-UVB ngonyaka. Ngenxa yobungakanani be-UVB, i-UVB ayifaki ukungena kwiglasi lula.
I-radiation ye-UVA, ngokuphambene nayo, bekuye kwacingelwa ukuba ibe nefuthe elincinci kwesikhumba. Izifundo ziye zabonisa ukuba i-UVA iyinxalenye ebalulekileyo yomonakalo wesikhumba. I-UVA igxininisa ngakumbi kwesikhumba kunye nobukhulu obungagculiseki kakhulu kwi-UVB.
Kwaye, ngokungafani ne-UVB, i-UVA ayikhethiweyo ngeglasi.
Imiphumo emibi ye-UVA ne-UVB
Zombini i-UVA kunye ne-UVB imisebe ingabangela i-plethora yezinto ezinxulumene nesikhumba, ezibandakanya imibimbi, izifo ezinxulumene nokuguga , umdlavuza wesikhumba, kunye nokukhuselwa komzimba kwisifo. Ngelixa singaziqondi ngokupheleleyo iinkqubo zolu tshintsho, abanye bakholelwa ukuba ukuchithwa kwe-collagen kunye nokubunjwa kwama-radicals amahhala kunokuphazamisa ukulungiswa kwe-DNA kwiqondo le-molecular.
Izaziso ze-UV ziyaziwa ukwenzela ukwandisa inani le-moles kwiindawo ezikhanyisiweyo zelanga. Ukugqithisa kwelanga ngokugqithiseleyo kunokukhokelela ekuphuhliseni izilonda ezihamba phambili ezibizwa ngokuthi i-actinic keratoses. I-actinic keratoses ithathwa njengento eqhelekileyo kuba enye kwi-100 iya kukhula ibe yi- squamous cell carcinoma . I-Actinic keratoses "i-bumps" ihlala ilula ukuziva kunokuba ibonwe kwaye iza kubonakala ngobuso, iindlebe kunye nesemva kwezandla.
Ukuvezwa kwe-UV kungabangela i- seborrheic keratoses , ebonakala ngathi izilonda ezinjenge-wart "zinamathele" kwesikhumba. Ngokungafani ne-actinic keratoses, i-seborrheic keratoses ayinomdlavuza.
I-Collagen Breakdown and Free Radicals
Imisebe ye-UV ingabangela ukuba i-collagen iqhekeke kwizinga eliphezulu ngaphezu kokuguga okuqhelekileyo . Yenza oku ngokungena kwinqanaba eliphakathi kwesikhumba (i-dermis), kubangele i-buildup engavamile ye-elastin. Xa ezi i-elastins ziqokelela, i-enzyme iveliswa ngokungahambi ngokugqithiseleyo i-collagen kwaye idale oko kuthiwa "izikhenkce zelanga." Ukuvezwa okuqhubekayo kukhawuleza kuphela kwenkqubo, okukhokelela ekuqhubaneni ukugubha kunye nokugubha.
Umbane we-UV ungomnye wabadali abakhulu be- radicals yamahhala . Ii-radicals zamahhala zi-molecule zomoya ezingazinzileyo ezine-electron enye kuneendawo ezimbini.
Ngenxa yokuba i-electron ifunyanwa ngamabini, i-molecule kufuneka ikhethe i-elektron ilahlekile yayo kwezinye iimolekyuli, kubangela ukuba i-chain reaction ingalimaza iiseli kwinqanaba le-molecular. Ama-radicals amahhala ayenzanga nje ukwandisa inani leenzyme ezidibanisa i-collagen, zinokuguqula izinto zezofuzo zeseli ngendlela engakhokelela kumhlaza.
Iimpawu zenkqubo yoMzimba
Umzimba unamasosha omzimba okhuselayo okubhekiselele ekuhlaseleni izifo kunye nokukhula okungavumelekanga kweseli, kuquka nomhlaza. Lokhu kukhuselo lwe-immune kubandakanya amaseli egazi abamhlophe abizwa ngokuba yi-T lymphocytes kunye neeseli zesikhumba ezibizwa ngokuba yiLangerhans cell . Xa isikhumba sichazwe kwi-sun excessively, iikhemikhali ezithile zikhutshwe zikhusele ngokuthe ngcembe ezi seteli, zonakalise ukuphendula kwamagciwane onke.
Le yindlela engekho yodwa apho ukuvezwa ngokugqithiseleyo kunokunciphisa umkhuhlane womntu. Umgca wokugqibela womzimba wokuzivikela ngomzimba into ebizwa ngokuba yi-apoptosis, inkqubo yokuzibulala "iseli" ekubhekiselele ekubulaleni iiseli ezinobungozi ziba nzima ukuba zibe ngumhlaza. (Esi sizathu sezizathu zokubangela ukutshatyalaliswa kwelanga.) Nangona le nkqubo ingacaciswanga ngokucacileyo, ukubonakaliswa kwe-UV ngokugqithiseleyo kubonakala kukuthintela i-apoptosis, ukuvumela iiseli ezinqabileyo ukuba nethuba.
Utshintsho lwesikhumba olwenziwa nguLanga
Ukuvezwa kwe-UV kubangele ukungqinanga kunye nokunqunyulwa kwesikhumba ebizwa ngokuthi i-solar elastosis, okubangelwa ukuguqulwa kwamaqabunga kunye ne-yellow discoloration. Inokubangela ukuba iindonga zemithambo yegazi zibe zincinci, ezikhokelela ekumanyeni okulula kunye nesiginci (i-telangiectasias) ebusweni.
Kukho utshintsho olunezona zinto eziqhelekileyo zokutshintshwa kwelanga zingu-freckles (i-lentigo yelanga). I-freckle ibangelwa xa iiseli ze-pigment-productive cell (i- melanocytes ) zonakaliswe, ezikhokelela ekukhuliseni isiphako. Amaninzi amakhulu, awaziwayo njengamabala obudala , ngokubonakalayo avela kwiminyango yezandla, isifuba, amahlombe, iingalo, nangaphezulu. Nangona iindawo zobuntwaba zihlala zibonwa kubantu abadala, abanxulumene nobudala njengoko igama labo libonisa kodwa ngenxa yokulimala kwelanga.
Ukuvezwa kwe-UV kungakhokelela ekubonakala kwimibala emhlophe kwimilenze, izandla, kunye neengalo njengoko i-melanocytes ichithwa ngokukhawuleza yimisebe yelanga.
I-Cancer neLelanoma
Ukukwazi kwelanga ukudala umdlavuza uyaziwa. Ezi zintathu zinkulu zomhlaza wesikhumba ziyi- melanoma , i- basal cell carcinoma , kunye ne-squamous cell carcinoma.
I-Melanoma yiyona nto ibhubha kakhulu kwezi zintathu njengoko zisasazekayo (i-metastasizes) ngokulula ngaphezu kwabanye. I-Basal cell carcinoma yinto eqhelekileyo kwaye iyanceda ukusasaza endaweni endaweni yokuhlaziya. I-squamous cell carcinoma yinto yesibini eqhelekileyo kwaye iyaziwa ngokuba yinto yokuxubusha, nangona ingaqhelekanga njenge-melanoma.
Kukholelwa ukuba isixa sokukhanya kwelanga umntu athola ngaphambi kokuba aneminyaka engama-20 yinto yokubeka ingozi kwi-melanoma. Ngokwahlukileyo, umngcipheko we-basal cell carcinoma okanye i-squamous cell carcinoma inxulumene nobomi besikhumba somntu kunye nomyinge wokuphila kwimibala ye-UV.
> Imithombo
- > Ratushny, V .; I-Gober, M .; Hick, R .; okqhubekayo. "Kusuka kwikeratinocyte ukuya kumhlaza: i-pathogenesis kunye nomzekelo we-squamous cell carcinoma." Umbhalo woPhando lweZliniki. NgoFebruwari 1, 2012; 122 (2): 464-472.
- > Narendhirakannan, R. noHana, A. "Ukuxinezeleka koxinzelelo kunye neCancer Cancer: Ingqwalasela." Ind J Clinic Biochem. Epreli 2013; 28 (2): 110-115.