Mtundu wa khungu anthu zikudalira chiyani? melanin pigment

Anthu ndi osiyanasiyana: wakuda, woyera, zofiirira ngakhalenso kuchoka kuwala kwa mdima. Khungu zimasiyanasiyana Africa ku Africa. Kumene zosiyanasiyana izi? N'chiyani chimachititsa a mtundu wa khungu la munthu? melanin ndi chiyani? Dziwani izi.

Melanin. Ndi chiyani icho?

Ngati ife kulankhula mu zamankhwala zimene melanin - ndi pigment amene apanga ku maselo a khungu otchedwa melanocytes. Ine ndikudabwa chomwe iye ali pano mu chochuluka nyama, kuphatikizapo anthu. Iwo amapereka khungu pigment melanin zosiyanasiyana mithunzi. Iwo apanga m'njira kuwiri, mtundu umene siyana kuchokera zachikasu woderapo ndi wakuda. Eumelanin - mawonekedwe melanin amapereka khungu mtundu bulauni. Mawonekedwe yachiwiri melanin - pheomelanin, amene ali pabuka-bulauni. Chifukwa pheomelanin anthu ndi madontho madontho kapena lamoto tsitsi lofiira.

Lero, chibadwa za amadziwa pafupifupi aliyense. Aliyense wa ife tinatengera kwa makolo ake akonzedwa DNA, kuphatikizapo amene ali ndi udindo mtundu wa khungu anthu. Majini yogwira maselo, ndi mdima mtundu wa khungu. Si kale kotheka kusunga nkhani wapadera mu banja limodzi, amene anabereka mapasa ndi mitundu yosiyanasiyana khungu. Koma kufooketsedwa ndi zinthu zina kuwonjezera kutengera za kumtundu kuti yopanga melanin.

Mmene melanin mu umunthu

Munthu aliyense pa dziko lino lapansi ali pafupifupi manambala wofanana melanocytes. Zimenezi zikutsimikizira kuti anthu onse padziko lapansili, kaya ndi woyera-khungu amuna kapena akazi wakuda ndi khungu chomwecho. Anthu amafunsa funso mu kaphatikizidwe melanin munthu chamoyo ndi zina kunja. Mothandizidwa cheza ultraviolet wa khungu anthu ayamba kutulutsa melanin kwambiri. Zimenezi zimathandiza kuteteza DNA kuwonongeka pakhungu la munthu.

Kufikira tsopano, mnjira sichinayambe ankafufuza mapeto, koma khungu lathu si kuonongeka chifukwa anachita zoteteza wa chamoyo. Ndipo anthu okhala pafupi ndi equator, kumene dzuŵa atenthe mopanda chifundo, khungu anakhala khalidwe mdima mtundu.

kulephera Program

Koma mwatsoka, mu malamulo, pali kuchotserapo. Today ife tingathe kuona matenda osowa - alubino. Iwo amakhala ndi kupanda melanin ku maselo a khungu. Zimenezi anati nyama ndiponso anthu. Tinasangalala kuonera nyama moyera-Mwachitsanzo, mukhoza kuona mkango woyera , kapena zazikulu woyera pikoko, koma ngati izo zimachitika kwa munthu, ndi chinthu chomvetsa chisoni. Munthu sangakhoze kukhala nthawi yaitali padzuwa, khungu lake yoyaka yomweyo. thupi amadwala kukhudzana kwambiri.

Pali munthu kulephera zambiri Mpambo chibadwa chifukwa cha imfa kupita patsogolo melanocytes - adzithandize. Pankhaniyi, khungu amakhala Umboni Wopereŵera. Kaya munthu khungu kapena chinayambira ku matenda nthawi zina limakhala loyera kwathunthu. Chifukwa, ndi khungu lakuda munthu ku chikhalidwe akhoza kukhala woyera. Mwatsoka, glitches majini ndi wosachiritsika lero.

Kuwala chikopa okhala dziko

Choona chidwi ndi oimira anthu woyera amapanga 40% lonse la anthu. Monga tanena kale, ndi chibadwa kuwala mtundu wa khungu la munthu chifukwa cha ntchito melanin mu maselo. Ngati timaona kuti anakakhala pa dziko anthu kutchula kuti gulu lina la mbali nkhope ndi mtundu wa dermis, ndiye pa nthawi kudzipatula gulu zinachititsa kuti pakhale wa mtundu kuwala chikopa. Zambiri za anthu awa amakhala ku Ulaya, Asia ndi Africa North.

Mtundu wa khungu anthu, monga tanenera kale, ndi amadalira zinthu zina. Mwachitsanzo, kumpoto kwa Ulaya, anthu dermis opepuka kuposa amwenye. dzuŵa ndi layamba kumpoto, kotero anthu oyera mosavuta thupi likusowa vitamini D. Ngakhale tisaiwale kuti pali anthu kumpoto amene ali khungu mokwanira mdima. Malinga ndi mfundo za asayansi, komanso zimadalira chakudya.

N'zochititsa chidwi, anthu ndi chilungamo khungu melanin mu zigawo chapamwamba cha khungu alipo m'mabaibulo umodzi. Diso mtundu ndi amadalira zimene wosanjikiza Iris wa lili wambirimbiri melanin. Ngati ndi wosanjikiza choyamba, maso adzakhala bulauni, ndipo ngati zigawo zinayi kapena zisanu, kuti moyenera, buluu kapena zobiriwira.

anthu akuda

Chiwerengero chachikulu ndi complexion mdima, akukhala ku Central ndi South Africa. Anthu m'dera lino nyengo imvera kwambiri padzuwa. Koma kukhudzana ndi cheza ultraviolet mu thupi amachititsa melanin kaphatikizidwe omwe ndi ntchito yake yoteteza. The chifukwa cha kukhudzana zonse kwa dzuwa ndipo anakhala mdima khungu.

Chinthu chapadera pa mlingo jini anthu ndi khungu lakuda maselo awo kubala melanin lalikulu zedi. Komanso ofufuza anapeza, wosanjikiza kumtunda kwa khungu anthu amenewa kwathunthu chimakwirira khungu pigment. Zimenezi amapereka khungu ake kuchokera bulauni pafupifupi wakuda.

Choona chidwi kuti melanin pigment limapezeka anthu akali chitukuko embryonic. Koma nthawi melanocytes kubadwa pafupifupi kutha kwa mwana thupi, ndipo pambuyo pa kubadwa, kuyamba kukhazikitsa kwambiri khungu. Anthu ambiri amadabwa akaona kuwala pa khungu lakuda ana amayi. chakuti ana lagolide ndi mdima pa miyezi ingapo.

Ndipo potsiriza,

Panthawi imeneyi, sayansi kuopsedwa chifukwa chakuti munthu khungu - chifukwa cha anatengera gulu lina la anthu kuti mphamvu cheza dzuwa mu malo awo okhala. Melanin Pankhaniyi amapereka ntchito chitetezo cheza ultraviolet ku dzuwa, pakalibe khungu lake kuti dryahlela mofulumira kwambiri. Komanso kukalamba, izo kumawonjezera kuthekera kwa khansa ya pakhungu.

N'zochititsa chidwi kuti akazi kwangochepetsako pang'ono mbandakucha khungu kuposa amuna. Ndicho chifukwa chomwe atsikana wakuda kuyang'ana owala kwambiri kuposa anyamata. Anthu ndi dermis kuwala, kusiyana ili pafupi negligible. Mwatsoka, masiku ano a mtundu zambiri amalenga olakwika. Kudulidwa kwa anthu pa maziko kawirikawiri zimenezi zimathandiza kuti tsankho. Koma ife tonse a mitundu imodzi ndipo anthu.