Long Haired Girl

Description
Construction of the root and strand
Hair is composed mainly of the protein keratin. Keratin assembles into rope-like intermediate filaments. The structure of these filaments provides strength to the hair shaft.
Hair growth begins inside the skin in a hair follicle. The only "living" portion of the hair is found in the follicle. The hair that is visible is the hair shaft, which exhibits no biochemical activity and is considered "dead". The base of the root is called the bulb, which contains the cells that produce the hair shaft. Other structures of the hair follicle include the oil producing sebaceous gland which lubricates the hair and the erector pili muscles, which are responsible for causing hairs to stand-up. In humans, with little body hair, the effect results in goose bumps.