ImpiloImithi

Umbala kwesikhumba womuntu kuncike kulokho? sombala i-melanin

Abantu abafani: abamnyama, abamhlophe, ensundu ngisho kusukela ukukhanya ebumnyameni. Ibala kuhluka izwekazi beya zwekazi. Uvela lokhu kuhlukahluka ngokunikeza? Yini enquma umbala kwesikhumba yomuntu? Kuyini i-melanin? Asivume.

Melanin. Kuyini lokhu?

Uma sikhuluma kukhulunywa ngezokwelapha lokho melanin - lo mbala ukuthi kuhlelwe kunamaqoqo amangqamuzana esikhumba okuthiwa melanocytes. Kazi yena ekhona omningi walo izilwane, kuhlanganise nabantu. Inikeza isikhumba sombala i-melanin ezihlukahlukene shades. It is kuhlelwe amafomu amabili ezinkulu, umbala okuyinto ziyahlukahluka kusuka ophuzi kuya konsundu kanye nabantu abamnyama. Eumelanin - ifomu melanin unikeza isikhumba umbala onsundu. Eyesibili ifomu melanin - pheomelanin, okuyinto iba nsundu ngokubomvu. Ngenxa abantu pheomelanin babe freckles noma amalangabi ngezinwele ezibomvu.

Namuhla, zofuzo mayelana uyazi cishe wonke umuntu. Ngamunye wethu uye ngofuzo kubazali bakhe iqoqo-chromosomes, kuhlanganise nalabo obhekene umbala kwesikhumba womuntu. Amangqamuzana bakhuthele kumaseli, lo mnyama umbala kwesikhumba. Akunjalo kudala kwakunokwenzeka bagcine icala eyingqayizivele omndeni owodwa, okuyinto wabeletha amawele ngemibala isikhumba ezahlukene. Kodwa bathonywe izinto zangaphandle ngaphezu yofuzo ekukhiqizeni i-melanin.

Umthelela melanin the human

Wonke umuntu kule planethi has cishe inani elifanayo labesilisa melanocytes. Leli qiniso kufakazela ukuthi bonke abantu emhlabeni, kungakhathaliseki ukuthi abelungu elinsundu noma abesifazane abamnyama isikhumba efanayo. Umbuzo in the zamagama zisifake melanin ngabanye kanye ezinye izici zangaphandle. Ngaphansi kwethonya emisebeni ultraviolet zesikhumba komuntu kuthoma ukukhiqiza melanin ngaphezulu. Lokhu kusiza ekunqandeni ukulimala kwe-DNA esikhumbeni indoda.

Kuze kube manje, le nqubo engakaze uphenyo kuze kube sekupheleni, kodwa isikhumba sethu alilinyaziwe ngenxa yokusabela okuvikela umzimba. Futhi abantu abahlala eduze nenkabazwe, lapho imisebe yelanga ukonakalisa kabuhlungu, isikhumba baba umbala walo isici amnyama.

Ukwehluleka Uhlelo

Kodwa ngeshwa, e imithetho, kunokuningi okungakhulunywanga ngakho. Namuhla singaba ukubona isifo ezingavamile - albino. It libhekene ukuntuleka kwe-melanin e kwamangqamuzana esikhumba. Le nqubo ibizwa ebonwe kokubili ezilwaneni. Sajabulela ubukele izilwane ezimhlophe, isibonelo, ungabona ingonyama omhlophe , noma omangalisayo peacock ezimhlophe, kodwa uma kwenzeka umuntu, ngempela yinto embi kakhulu. Umuntu akakwazi ukuba isikhathi eside elangeni, isikhumba sakhe burns kweso. Umzimba uhlushwa ukuchayeka ezinzima.

Kukhona eyodwa ukwehluleka ngaphezulu isimiso sezakhi zofuzo okubangelwa ukulahlekelwa okuqhubekayo melanocytes - Une-vitiligo. Kulokhu, isikhumba kuba zinamabala. Noma yini umuntu lesikhumba noma elanqoba lesi sifo ngezinye izikhathi kuba mhlophe ngokuphelele. Ngenxa yalokho, umuntu abanebala elinsundu imvelo bangaba ngokuphelele white. Ngeshwa, glitches zofuzo azinakulungiswa namuhla.

Izakhamuzi abanesikhumba esimhlophe planethi

Kuvele Eqinisweni ezithakazelisayo wukuthi abameleli abelungu bakha 40% wayo yonke lwesintu. Njengoba sishilo, kuyinto umbala zofuzo ukukhanya isikhumba womuntu kubangelwa umsebenzi melanin kumaseli. Uma sicabanga ukuthi sahlala abantu iplanethi yayingagwegwesi oluthile izici ebusweni nangokuzwa umbala dermis ke ngokuhamba kwesikhathi inyumbazana ngenxa iqembu zaholela ekwakhekeni of uhlanga abanesikhumba esimhlophe. Kwenqwaba balaba bantu bahlala e-Europe, Asia naseNyakatho Afrika.

Umbala kwesikhumba womuntu, njengoba sekushiwo, kubuye sincike iziphi izici zangaphandle. Ngokwesibonelo, e-Northern Europe, abantu babe dermis alula kakhulu kunomoya Asians. Imisebe yelanga mancane abakhuthele enyakatho, ngakho abantu emhlophe kulula ukuthola umzimba udinga kavithamini D. Nakuba kufanele kuphawulwe ukuthi kukhona abantu enyakatho abanale isikhumba ngokwanele amnyama. Ngokusho imibono yososayensi, futhi kuncike ukudla.

Ngokuthakazelisayo, abantu fair isikhumba melanin ezingqimbeni engenhla epidermis elikhona amakhophi olulodwa. umbala Eye kubuye sincike kulokho ungqimba iris itholakala semali melanin. Uma lokhu ungqimba wokuqala, amehlo kuyoba ansundu kakhulu, njalo uma izingqimba ezine noma ezinhlanu, ukuthi, ngokufanele, blue noma oluhlaza.

abantu abanebala elinsundu

Labantu main kokuba amnyama, abahlala eMelika Ephakathi naseNingizimu Afrika. Abantu kule ndawo zezulu angaphansi okukhulu elangeni. Kodwa ukuchayeka emisebeni ultraviolet emzimbeni womuntu kubangela i-melanin zamagama okuyinto has a function zokuzivikela. Waba yini umphumela wesibindi ukuchayeka njalo uye elangeni uphinde waba isikhumba omnyama.

Isici ehlukile ezingeni isakhi sofuzo kubantu abanesikhumba abamnyama ukuthi amaseli wabo ukukhiqiza melanin inqwaba. Ngaphandle kwalokho, njengoba abacwaningi bathola, ungqimba engenhla epidermis abantu abanjalo ihlanganisa ngokuphelele sombala isikhumba. Leli qiniso unika ibala layo kusukela brown ukuze cishe abamnyama.

Kuvele Eqinisweni ezithakazelisayo ukuthi sombala i-melanin livela abantu namanje ekuthuthukisweni sombungu. Kodwa ekuzalweni melanocytes cishe zinyamalale kusukela ingane umzimba, futhi emva kokubelethwa, bacale kutfutfukisa ngokushesha esikhumbeni. Abantu abaningi bayamangala lapho bebona ukukhanya abanebala elinsundu izingane umama. Iqiniso lokuthi izingane zizalwa ezimhlophe futhi mnyama phezu ezinyangeni ezimbalwa ezizayo.

Futhi ekugcineni,

Ngalesi sikhathi, isayensi wacasulwa Iqiniso lokuthi umuntu ibala - kuwumphumela lithathelwe iqembu elithile labantu ukuba ukushuba emisebeni yelanga endaweni yokuhlala yabo. Melanin kulokhu inikeza imisebenzi isivikelo emisebeni ultraviolet okuvela elangeni, ngokungabi bikho isikhumba sakhe esasiyoba dryahlela ngokushesha okukhulu. Ngaphezu ukuguga, it kwandisa kungenzeka umdlavuza wesikhumba oyingozi.

Kuyathakazelisa ukuthi abesifazane babe isikhumba kancane alula kakhulu kunomoya amadoda. Yingakho amantombazane black bheka licace okuningi kunentsha. Abantu ne dermis ukukhanya, lo mehluko cishe azinakwa. Ngeshwa, ezweni lanamuhla umbala ngokuvamile kudala eyeqisayo. I ukwehlukaniswa kwesintu leso ngesisekelo salokhu sivame ukuholela yobandlululo. Kodwa sonke yilunga zohlobo olufanayo futhi abantu.

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