The Malleability And Elasticit Essay, Research Paper

I. Introduction

As result of genetic differentiation, every single person in the world has distinct hair, but the main differences between hair types are in texture and thickness. These variations are caused by the genetic make up of the fibers that make up the hair and follicles that generate the fibers. Hair is made from keratin (protein) that is wound in a coil. The turns of the coil are held together in hydrogen bonds. By wetting the hair and applying heat, the bonds (shape) of the hair can be altered. But for how long can the bonds stay like that? What factors act on the hair to make it change back? Will a thicker hair follicle reshape more readily than a thin hair follicle? Does curly hair straighten easier than naturally straight hair curls? Do the hydrogen bonds stretch and how far? Does thicker hair have more elasticity than thin hair? It is expected that the hair will maintain it s changed shape until exposed to a form of water and a thinner follicle reshape easier than a thicker one, straight hairs should accept a new shape more readily than curly and a thick hair will have more elasticity than a thinner one.

The hair fiber is the core part of the hair structure. It is made in the follicle. Those cells made in the center of the hair follicle become the cortex cells. As the cells multiply, they are pushed upwards towards the skin surface. Now they begin to differentiate into different cell types. The cortex cells change from a round into a flattened appearance. They are squeezed together into layers called lamella. As the cells pass the melanocyte cells, melanin pigment is added. The cells become keratinized and harden. When they completely harden, it becomes impossible for the cells to function properly and the cells die. The keratinized cells are then pushed away from the hair follicle region as new cells come up underneath. The cortex cells are now part of the dead keratinized fiber and what is seen as a strand of hair.

There are three types of hair. Lanugo hair is solely found on a developing embryo in the fetus. Vellus hair is short, fine, unpigmented hair found mainly on the cheeks and nose. Terminal hair is hair found everywhere else on the body. The type of hair tested in the experiment was terminal hair. The specific type of terminal hair used was scalp hair. A major factor of influence on hair is race. Caucasian hair can be quite variable in its presentation. The fiber can be circular or oval in cross section and is on average thinner than Asian hair. African American hair is frequently tightly coiled, or spiral hair. The fiber is elliptical or sometimes very flat and ribbon-like. There is more rigidity to the fiber across the area of large cross section but the hair is much more pliable across the narrow section. This causes the hair to coil and curl along the along the length. These differences in fiber and hair appearance are caused deep down at the beginning, where the hair is made. Different hair fiber types are produced by different hair follicles. Large straight hair follicles with a circular cross section produce thick straight hair. Curly flat hair follicles make curly elliptical or ribbon shaped cross section hair. The shape of the hair follicle is the mold for the shape of the fiber. When the cells are added to the fiber in the follicle, they are soft and pliable. As the cells are keratinized in the follicle, they take on the shape of the follicle. Hence curly hair follicles make curly hair fibers. There are also racial differences in the chemical composition of the fiber. African American hair has lower sulfur protein compared to high sulfur protein that is observed in Asian and Caucasian individuals.