Leslie Correa is a nationally renowned hair designer and hair chemical specialist, (Color, Perms, Relaxers) he has devoted the past 24 years perfecting his craft in the art of hair design. He has devoted his career to knowing how to refine the best qualities of your hair and bringing out its natural beauty. Based in New York and traveling to work with some of Europe's and America's highly recognized design teams, Leslie takes a realistic approach to hairstyling and has developed a personal design style allowing him to create looks that highlight a person's best features.

Trauma to Hair Follicles (Part 3)
What Actually is Hair?

Hair is the slender, threadlike outgrowth from the skin of mammals.
Insulation from cold, protection against dust and sand, and camouflage are among the functions of hair.

Each hair originates in a deep, pouch like follicle, which contains the bulb-shaped root of the hair. The papilla, a net of nerves and capillaries that supplies the hair with nutrients, extends into an indentation at the base of the root. Here, newly dividing cells force older cells upward where they die and harden into the hair shaft. The shaft has two layers: the colorless cuticle and the cortex, which contains pigment and the protein keratin. Hair is lubricated by oil from sebaceous glands in the follicle. Hair is composed of a hardened protein called keratin. There are three distinct layers to hair:

• Cuticle – The cuticle is the outermost layer of the hair shaft. Composed of hardened translucent cells of keratin proteins, the cuticle has an appearance like scales on a fish, one scale overlapping the other. The cuticle provides protection, flexibility, strength, and sheen. The cuticles are tightly wrapped around the hair, protecting it from the elements.
  
  
• Cortex – The cortex is under the cuticle and is related to hair volume. Melanocytes contained in cortex contain the melanin, or the pigment granules, which determine hair color. The cortex embodies the bulk of the interior structure of the hair and is made largely of keratin proteins. The cortex contains the polypeptide chains, which are chains of amino acids. It is in the cortex that the sulfur bonds are directly affected by ammonia, peroxide, ammonium thioglycolate and hydroxides; these are ingredients in relaxers, permanent wave lotions, bleach & color.
  
  
• Medulla – The medulla is the innermost center of hair, which is about 10% of volume, except in thin hair when the medulla may be absent.
  

• Root – The root is living part of the hair anchored in the scalp. At the end of the root is the bulb, a thicker whitish structure.
  
  
• Papilla – The empty area at the base of the bulb connecting the hair to the head. This is where the blood vessels and nerves give the hair its nourishment.

Part 4 of the series "Why Do Some of Us Lose It? "