Hair is actually a filamentous type of biomaterial which commonly grows from the hair follicles located in the dermis of the skin. The entire body is covered with these follicles which produce either fine hair or thick terminal hair. Hair can only be found in mammals. Insects also have certain filamentous outgrowths but those cannot be referred to as hair in the scientific sense of the meaning. These are called trichomes and they can also be found on various different sorts of plants as well. Hair actually has two distinct structures. The hair follicle is the first structure located under the skin. The second part of the structure is the hard, filamentous shaft which actually extends above the surface of the skin. This shaft can be divided into three distinct zones. The cuticle is the first zone and it has several layers of flat cells which overlap one another very similarly to the roof shingles. The second part of the structure is the cortex which is known for containing the keratin bundles. The third part of the structure is located at the fiber’s center and is known as the medulla.