|
|
 Hair is composed of a hardened protein called keratin. There are three layers to hair:
Cuticle — external layer of hair formed from hardened cells. It is scaly in nature and gives hair texture.
Cortex — Under the scalp and related to hair volume. The cells of the cortex contain keratin and melanin (pigment).
Medulla — Innermost center of hair, which is about 10% of volume, except in thin hair when the medulla may be absent.
Root — the living part of the hair anchored in the scalp. At the end of the root is the bulb, a thicker whitish structure.
Papilla — 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.
Everyone has approximately 100,000 hairs, and hair cycles every 2 to 6 years (average is 3 years) and is genetically programmed. |
|
