Hair... the basics!
There are not many places on our bodies which are not covered by some kind of hair. It is obvious on our scalp, armpits, legs, pubic area, arms and eyebrows, lids, the chest and face (on men).
- The Structure
The part of the hair we can see is called the shaft. The shaft is connected to a part of the skin called the follicle. The shaft is formed from a protein called keratin and is made of dead tissue. The hair develops from a root which is at the end of the follicle in the scalp and is fed and nourished by the bloodstream. The root is about 3 - 5 mm deep in the skin on the scalp. The daily rate of growth is between ¼ - ½ mm. If the root is damaged, the hair may fall out and never regrow.
A sebaceous gland is also in the follicle. This gland secretes a greasy substance called sebum. The sebum lubricates the hair shaft and the skin around the shaft and can also give the hair a greasy look.
The follicle also contains small muscles which contract when you are nervous, cold, afraid or shocked. The hair shaft them stand on end and gather up the skin around the shaft to form goose pimples.
Hair growth is not continuous all throughout our lives. Hair goes into resting phases when not growth takes place. The hairs which are resting become clubbed in shape and lose the normal pigmentation. Only about 10% of our scalp hairs are in this resting phase at any one time. The follicles are not damaged during this time and it is totally normal for the hairs to fall out, when the hair have stopped resting they will grow again.
A substance which lines the follicles and is mixed in with the keratin is a pigment called melanin. This stains the keratin and gives the hair its colour. The colour is part of your individual genetic make-up. As we age, the melanin stops being produced and we go grey. The time which this starts happening can be affected by heredity, continuous stress and worries and emotional shock.