A hair can be defined as a slender, thread-like outgrowth from a follicle in the skin. The hair are present all over the body, except for the sole, palm, lips. Hair is composed of structural protein called keratin. This is the same kind of protein that makes up the nails and the outer layer of skin.
Hair comprises of three morphological regions - the cuticle, medulla, and cortex
- An innermost layer or medulla which is only present in large thick hairs.
- The middle layer known as the cortex. The cortex provides strength, colour and texture of the hair.
- The outermost layer is known as the cuticle. The cuticle is thin and colourless. It serves as a protector of the cortex.
Structure of the hair root
Hair root lies below the skin, which is enclosed within a follicle. At the base of hair follicle is the dermal papilla. The dermal papilla is fed by the blood vessels which carries nourishment to produce new hair. The dermal papilla is very important for the growth of the hair as it contains receptors for male hormones and androgens. The presence of these receptors is responsible for the androgenetic alopecia.