Description - Hair
⦁Hair is a protein filament that grows from follicles found in the dermis, or skin.
⦁Hair is focused on hair growth, hair types and hair care, but hair is also an important biomaterial primarily composed of protein, notably keratin.
⦁Each strand of hair is made up of the medulla, cortex, and cuticle.
⦁The shape of the follicle determines the shape of the cortex, and the shape of the fiber is related to how straight or curly the hair is. People with straight hair have round hair fibers. Oval and other shaped fibers are generally more wavy or curly.
⦁Hair growth begins inside the hair follicle. The only "living" portion of the hair is found in the follicle.
⦁The root is lodged in a follicular involution of the epidermis called the hair follicle.
⦁The base of a hair's root (the "bulb") contains the cells that produce the hair shaft.
⦁All natural hair colors are the result of two types of hair pigments. Both of these pigments are melanin types, produced inside the hair follicle and packed into granules found in the fibers. Eumelanin is the dominant pigment in brown hair and black hair, while pheomelanin is dominant in red hair. Blond hair is the result of having little pigmentation in the hair strand. Gray hair occurs when melanin production decreases or stops, while poliosis is hair (and often the skin to which the hair is attached), typically in spots, that never possessed melanin at all in the first place, or ceased for natural genetic reasons, generally, in the first years of life.
⦁Hair grows everywhere on the external body except for mucus membranes and glabrous skin, such as that found on the palms of the hands, soles of the feet, and lips.