The total number of hair follicles for an adult person is
estimated at 5 million with 1 million on the head of which 100,000
alone cover the scalp. The only external regions of skin without
hair follicles are the palms of the hands and soles of the feet. At
the base of the follicle is a small structure that is called the
papilla. This is the actual cell-producing structure where the hair
strand is constructed. The papila is shaped like a cone, protruding
into the bulb of the growing hair. Also attached to the follicle is
a tiny bundle of muscle fiber called the arector that is
responsible for causing the follicle and hair to be come more
perpendicular to the surface of the skin, and causing the follicle
to protrude slightly above the surrounding skin. This process
results in goose bumps.
The structure of hair follicles is basically the same, though for
example the shape may differ a little for differnt kinds of hair,
for example the follicles of the pubic hair are more flat then the
follicles of the hair on the head.
Specialised hair such as eyebrows and eyelashes protect the eyes by
channelling or sweeping away fluids, dust and debris. Nasal hair
plays an important role in trapping air borne foreign particles
before reaching the lungs. Pubic and armit hair serve to trap the
pheromones produced under the armits and in genital area, this is
for the purpose of attracting the other gender.
