When you think of your hair, you probably think of the hair on your head. But
there's hair on almost every part of your body. (Some places that don't have
hair include the lips, the palms of the hands, and the soles of the feet.)
Some of the hair on your body is easy to see, like your eyebrows and the hair
on your head, arms, and legs. But other hair, like that on your cheek, is almost
invisible. Depending on where it is, hair has different jobs. The hair on your
head keeps your head warm and provides a little cushioning for your skull.
Eyelashes protect your eyes by decreasing the amount of
light and dust that go into them, and eyebrows protect your eyes from sweat
dripping down from your forehead.
Hair Comes From Where?
Whether hair is growing
out of your head, arm, or ankle, it all rises out of the skin in the same way.
It starts at the hair root, a place beneath the skin where cells band
together to form keratin (the protein that hair is made of). The root is inside
a follicle (say: fah-lih-kul), which is like a small tube in the
skin.
As the hair begins to grow, it pushes up from the root and out of the
follicle, through the skin where it can be seen. Tiny
blood vessels at the base of every follicle feed the hair root to keep it
growing. But once the hair is at the skin's surface, the cells within the strand
of hair aren't alive anymore. The hair you see on every part of your body
contains dead cells. That's why it doesn't cause pain when someone cuts your
hair with scissors!
Nearly every hair follicle is attached to a sebaceous (say:
sih-bay-shus) gland, which is sometimes called an oil gland. These
sebaceous glands produce oil, which makes the hair shiny and a bit waterproof.
Sometimes, like during puberty, these glands can pump out too much oil and a
person's hair may look greasy. Time for a shampoo!
Hair Today, Gone Tomorrow!
You have more than
100,000 hairs on your head, but you lose some every day. About 50 to 100 hairs
fall out each day, while you're washing your hair, brushing or combing it, or
just sitting still. But don't worry, new hairs are constantly replacing those
that have fallen out.
Each hair on your head grows for about 2 to 6 years. Then it rests for a few
months and finally falls out. It is replaced by a new hair, which begins to grow
from the same hair follicle. This cycle of hair growing, resting, falling out,
and being replaced helps to maintain just the right number of hairs on your
head.
If hair is not cut, it can grow up to 5 feet (152.4 centimeters) long!
But this takes a long time. You've probably noticed that hair on your head grows
slowly - only about 1/2 inch (12.7 millimeters) every month. At that rate, it
would take 10 years to grow your hair to 5 feet (152.4 centimeters) long!
Hair Comes in Many Colors
What kind of hair do
you have - black and curly, blond and straight, or some other combination? Hair
color comes from melanin (say: meh-luh-nun), the substance that
gives hair and skin its pigment. The lighter someone's hair, the less melanin
there is. A person with brown or black hair has much more melanin than someone
with blond or red hair. Older people lose the melanin pigment in their hair as
they age, making their hair look gray or white.
Often, a person's skin color goes with the color of his or her hair. For
example, many blondes have light skin, whereas many people with darker skin have
dark brown or black hair. And don't forget genes (genes are what you
inherit from your parents): Usually, a kid's hair color is determined by one or
both parents' hair color.
When it comes to type, your hair follicles make a difference. Some hair
follicles are structured in a way that produces curly hair, whereas others send
out straight hair. Follicles also determine if your hair will be thick and
coarse or thin and fine.
Taking Care of Hair
With hair, the main thing
is keeping it clean. Some people wash their hair every day, but others do it
just once or twice a week. It depends on your hair and what kind of things
you've been doing, like exercising or swimming.
When you wash your hair, use a gentle shampoo and warm water. Lather up using
your fingertips, rather than your fingernails. You might use a conditioner or a
shampoo containing a conditioner. This can take the tangles out or your hair and
make it look smooth. But depending on your hair, it can also make it look flat
and oily. Rinse your hair with plenty of clean water. Dry it gently with a towel
and use a wide-tooth comb to untangle it.
Be kind to your hair - wet or dry - by being gentle when you comb or brush
your hair. Don't yank on knots too hard and don't wear your ponytails and braids
too tight. This can irritate your scalp. And if you use curling irons or
blow-dryers, be careful and ask for adult help when needed. You don't want to
burn yourself.
Here's an easy way to have great-looking hair: Eat a healthy diet. It's not as
weird as it sounds. A nutritious diet helps your body from the inside out!
Updated and reviewed by: Elana Pearl Ben-Joseph,
MD
Date reviewed: August 2004
Originally reviewed by: Steven Dowshen,
MD