以前,一些上了岁数的人想让白发变黑,便采取染发的办法。如今,为了追求时尚,不同年龄段的人也都加入了染发一族,放眼大街,赤橙黄绿青蓝紫,好不热闹。那么,头发是如何“变色”的呢?我们的头发从表面到内部,分别为表皮层、皮质层和髓质层。表皮层由半透明的毛鳞片覆盖,起到保护头发的作用。皮质层含硬角蛋白和黑色素。最里面为髓质层,由角化的细胞组成,内含有空气。当色素细胞停止 In the past, some aged people wanted to make their hair darker and they adopted the method of hair coloring. Today, in order to pursue fashion, people of all ages have also joined the hair family, looking into the streets, red, yellow, green and blue, very lively. So how does the hair “color ”? Our hair from the surface to the interior, respectively, the epidermis, cortex and medulla layer. The epidermis is covered with translucent cuticle to protect the hair. The cortex contains hard keratin and melanin. The innermost layer of the medulla, composed of keratinocytes, contains air. When the pigment cells stop