Is your Hair Dead or Alive?
I am sure you have heard someone say that it doesn't matter what you do to your hair - it's dead anyway. But is it? No and yes. The hair that we see outside our scalp are dead as it has no blood or nerves. A healthy hair can be stretched up to 30 % of its total length and said to have high insulating powers. We change our hairstyles, hair colour, texture, style it and even pull it to an amazing degree, and yet despite all of this abuse, healthy hair can remain resilient and tough.
Hair Composition
Hair is composed of keratin, a fibrous protein, and is build from cells not unlike those of the skin. The hair shaft consists of three layers: the outer cuticle, composed of overlapping cells, like fish scales or roof shingles; the cortex, comprising the hair's main bulk and colour; and the medulla, a thin core of transparent cells and air spaces.
Learn more about Hair Structure, Hair Texture, hair Types
The nerves and the muscles give the hair its tactile properties, allowing the slightest movement to be felt. When the muscles contract, the hair stands up more and pinches the skin, causing 'goose bumps'. We inherit this characteristic from animals - the bristling quills of a porcupine and the hairs of a cat are exaggerated examples, as are the extremely sensitive whiskers of the cat family. The crinkling of sheep's wool is due to irregular contractions of the follicle muscles (called arrector pili) which change the shape of the follicle and, therefore, the characteristics of the wool produced. Again, hair is remarkable: its cell reproduction is the second most prolific of the human body, bone marrow being the first. This means that our hair is extremely sensitive to changes going on within the body, and it is often as a result of these internal problems that hair loss can occur.
|
