Hair is, to a great extent, protein. It grows about one centimeter per month which, compared to other tissues of the body, is very fast. However, it is slow if you are waiting for your hair to regrow. Scalp hair has a life of about four years and grows within indentations in the skin known as hair follicles. There are about 120,000 follicles on the scalp.
The ‘production center’ for the hair is the hair bulb were cells are constantly dividing and, here, pushing the cells above in an upward direction. Thus, the hair grows.
Below the hair bulb is the papilla which serves as the communication link between the hair and the rest of the body. The body’s blood supply circulates through the papilla and provides the nourishment necessary to keep the hair growing.
Blood is the means by which so many things are transported through the body - foods, waste products, drugs, poisons, and hormones, to name a few. Because the blood transports these things to and from the hair papilla, the hair itself is influenced by all these factors. Indeed, the hair is so sensitive - due to its high rate of growth - that hair loss may be the first sign that something internal is wrong with you.
A hair, then, can provide clues for the diagnosis of certain internal bodily problems. The manner in which hair is lost can also give important clues as to the cause of the loss:
- From all over the scalp or from specific areas?
- From one spot or many?
- With or without sharply defined margins?
- With or without the hair follicles being destroyed?
- Quickly or slowly?