Keratinization of Hair

Although both the hair and the epidermis contain keratin, there are differences in their keratinization. For example, the keratin of the hair's cortex and cuticle is harder than that of the epidermis; keratinized hair cells remain tightly attached to one another, whereas those of skin are continuously sloughed; keratinization of the hair is intermittent and is restricted to the bulb, whereas that of skin is continuous and occurs over the entire surface; and keratinized cells of the epidermis are identical, whereas those in hairs differ in structure and function depending on their position in the hair.