Human hair Structure and composition and Hair growth cycle and Functions of human hair
Human hair Human hair is a unique and complex fibrous structure found on most external areas of the human body, except for areas like the palms of the hands and soles of the feet. Structure and composition Hair consists of two main parts: Hair follicle: A tube-like structure within the skin, it anchors the hair and is the living part where new hair cells are produced and grow. Hair shaft: The visible, hard, filamentous part that extends above the skin surface and is considered "dead". The hair shaft is made up of three layers: Cuticle: The outermost protective layer, composed of overlapping cells that repel water. Cortex: The highly structured and organized middle layer, containing keratin bundles and melanin granules that determine hair color. Medulla: The innermost, disorganized area at the center of the fiber, which may or may not be present. Hair is primarily composed of keratin , a fibrous protein that is...