hair

Hair is a protein filament that grows from follicles found in the dermis. Hair is one of the defining characteristics of mammals. The human body, apart from areas of glabrous skin, is covered in follicles which produce thick terminal and fine vellus hair. Most common interest in hair is focused on hair growth, hair types, and hair care, but hair is also an important biomaterial primarily composed of protein, notably alpha-keratin. Attitudes towards different hair, such as hairstyles and hair removal, vary widely across different cultures and historical periods, but it is often used to indicate a person's personal beliefs or social position, such as their age, gender, or religion. The study of hair is called trichology. Terminology The English word "hair" typically refers to two distinct structures: 1) The part beneath the skin: the pilosebaceous unit consists of the hair follicle, sebaceous gland, erector pili muscle, and arrector pili muscles; plus the associated secondary structures (arrector pili muscles and apocrine sweat glands) which are not unique to the scalp. 2) The shaft: otherwise known as the cuticle or cortex (inner structure or med

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