Читать книгу Why Are Black Women Losing Their Hair - Barry Fletcher - Страница 7

To better understand the underlying causes of damaged hair, we must familiarize ourselves with our hair's structure.

Contrary to popular belief, hair is a living organism, and like skin, teeth and nails, the hair extracts its nourishment from the blood stream. This is why diet plays such an important role in the maintenance of healthy hair. Each hair strand is made up of three principal components. The first is the cuticle or outer-most layer. It acts as a protective shield to the hair shaft and is coated with a natural lubricant called sebum, which gives hair its natural sheen. When hair appears dull and dry, this means the sebum has been stripped from the hair shaft. This is usually the result of over-processing, excessive heat or improper product usage.

The second layer of the hair strand is the cortex. The cortex determines the color, strength, elasticity and texture of the hair and accounts for 75 to 90 percent of the hair's bulk. If the cortex is damaged, the hair will appear fragile and weak and will break easily when touched. Deep conditioning and regular treatments are essential to maintaining and strengthening the cortex.

The third and final innermost layer of the hair is the medulla, also referred to as the marrow of the hair shaft. The medulla is frequently broken or entirely absent from the hair shaft. It is suspected that poor health and the use of certain drugs have a direct bearing on its absence or damaged condition. The exact function of the medulla remains a mystery. The hair does not appear to suffer from its absence.