Cosmetics, Hair, And Nails

This chapter discussed the development and types of hair and the function of nails, both of which are modified epidermal cells classified as skin appendages. Human hair structures form between 9 weeks and 4 months after conception, starting from the head and progressing down the body. Hair is categorized into terminal and vellus types, with vellus hair transitioning to terminal hair during puberty. Nails, composed of tough keratin, grow from the epidermis of the toes and fingers, providing protection, aiding in grasping fine objects, and enhancing the strength of fingers and toes.