A mature strand of human hair consists of which two principal parts?

A mature strand of human hair consists of the hair root and the hair shaft. The hair root is the part of the hair that is embedded in the follicle beneath the skin, while the hair shaft is the visible part of the hair that extends above the surface of the scalp. The hair shaft is composed of tightly packed keratinized cells and is responsible for the hair's overall appearance and properties, such as texture and color.

The hair root anchors the hair in place and is vital for hair growth, as it is where new hair cells are generated. This growth occurs at the hair bulb, which is found at the base of the root, but it is specifically the root and shaft that make up the two primary components of a mature strand. Understanding these parts is essential for those studying cosmetology, as it relates to hair health, growth, and various hair care practices.