General Hair info

Our bodies are completely covered by hair except for the lips, palms of the hand and soles of the feet. Different sights have different densities of hair. Each hair is made up of a structure of dead cells filled with protein called Keratin hair develop in a tiny tube called a follicle which is situated below the surface of the skin. All follicles we have are present at birth and generally amount to about 5 million. Of this 100,000 - 200,200 are located on the head Our hair grows about 15cm per year.One hair takes approx. 3 years from the time it starts to grow to the time it drops out. We lose approximately 100 hairs daily when brushing,washing our hair etc. There are two types of hair - Vellus hair which is fine and downy which is found on the body. Terminal hair which is longer and darker and found on the scalp, eyebrows,pubic area, etc. the function of the hair is to act as  an ante nnae for touch sensors located in the base of each hair. Scalp hair cushions blows to the head [ really???],protects us from sunburn. Nose hair filters out particles of grit and dust,eyelashes prevent foreign bodies getting into our eyes and eyebrows act as sweat bands. Jenny - taken from news letter of Trich support group - Edenhope.Victoria.Australia

Some more info on hair (by Mike Grant)

<< But it's probably too much of a coincidence that all my gray patches are
where I tend to pull the most! Has anyone got a (scientific) explanation for
this?>

Pulling damages the pigment sac in the follicle. The results sometimes occur
after a traumatic injury to the head. Like with the hair producing part of
follicle, there is recovery up to a point when the follicle has been damage
enough over a sufficiently long period of time it can no longer recover.

The follicle is like a tube of toothpaste that squeezes out new hair. When
the follicle ceases to continously produce hair renewing the attachment
between the hair and the living hair producing tissue around it, the bond
quickly deteriorates and the hair falls out. So when the growth of hair
stops, say by a chemotherapy agent, severe malnutrition, or the hair has
naturally reach the end of its life cycle, the hair is soon shed.

Contrary to the popular notion and appearances, a persons hair does not cease
to grow once it reaches a certain length. The follicle has no way of knowing
if the hair attached to it is a millimeter long or a meter long. The maximum
length a hair can attain, if uncut, it call the terminal length and is a
product of the span of the hair's grow cycle and the rate at which the hair
grows during it's growth phase. Hair on different parts of the body have
different growth rates and lifespans to yield different terminal lengths. For
example, as a man, the hair on my legs seems not to grow, that is, it's always
about an inch or less without ever being cut. However, any woman who shaves
her legs can attest to the fact that leg hair grows quick rapidly. What
happens is leg hair, like other body hair, has a short life cycle and sheds
before it can attain any significant length. What accummulates in my shower
drain attests to the rate the length at which I shed my body hair.

Scalp hair also has a terminal length that varies with the individual. Men's
hair has a shorter terminal length than women as rule. Some women can grow
their hair down to the floor while the length of other women's hair may not
exceed more than a dozen inches or less even if uncut.

Probably more than you wanted to know about hair growth.

Mike Grant