Hair is generally simple in structure but has all essential elements in social functioning. It is made up of a tight protein called keratin. A hair follicle anchors each hair into the skin.
The hair bulb forms the base of the hair follicle. In the hair bulb, living cells separate and grow to build the hair shaft. Blood vessels nourish the cells in the hair bulb and deliver hormones that modify hair growth and structure at different times of life.