Pourquoi existe t-il plusieurs couleurs de peau ?

Il y a 30.000 ans, la Terre a connu plusieurs importantes périodes glaciaires. Nos ancêtres ont alors parcouru les 5 continents en recherche de nourriture. Durant leur quête, ils se sont habitués aux nouveaux climats et ont progressivement changé, physiquement ainsi que leur couleur de peau. C’est dû à la présence plus ou moins importante de petits grains colorés dans la couche de l´épiderme (couche supérieure de la peau), qui explique l´extraordinaire diversité de couleur appropriée par la peau.

Ces grains correspondent à des pigments de mélanine, qui sont fabriqués en permanence. Plus y a de présence de ces pigments dans la peau, plus la peau apparaît foncée. Selon les différents couleurs de peau, les grains de mélanine sont disposés de manières différentes : pour les peaux claires, ils forment des petits paquets isolés et pour les peaux foncées, ils sont dispersés dans toutes les cellules de l’épiderme. Les pigments de mélanine sont contrôlés par les gènes hérités de nos parents, par des cellules de l’épiderme : les mélanocytes

La mélanine colore la peau mais protège aussi du soleil. Elle absorbe une partie des rayons ultraviolets, qui sont responsables de nos coups de soleil. La mélanine est un filtre naturel, qui est plus ou moins actif selon l’ensoleillement. Dans les parties du globe où les rayons du soleil sont les plus forts, une peau foncée protège mieux qu’une peau claire : notre corps s’est donc adapté à son environnement au fil des temps.

ngaje Barcelona, rasage, bio, cosmetique, après rasage, crème de jour

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