Humans are hairy.
If you think that humans are pretty hairless creatures, you're wrong. All, we mean ALL, over
your body, except for your lips, palms of your hands and soles of your feet are hairs, big and
small. By the time you're an adult, you're likely to have about 5 million hairs growing out of your
skin -- about the same number as a gorilla! The only difference is that most of a gorilla's hair is
thick and long, and most of a human's is so thin and small it is extremely hard to see. You've got
to look closely!
What is hair?
Hair is made of the same stuff that's found in horse hooves, bird feathers, antlers, horns,
and your cat's or dog's claws and your fingernails! It's a body protein called keratin and it grows
out of a minuscule opening of the skin called a follicle.
Why is some hair curly, some hair straight?
It all depends on the shape of the follicle out of which the hair is growing. Straight hair
lies flat because it's round and grows out of round follicles. Curly hair bends because its
cross-section is an oval. It comes out of oval follicles.
What makes some hair dark, some light, and some entirely white?
The same chemical pigment that determines skin color -- melanin. Not having melanin in your
body gives you white hair; a little makes you strawberry blond; more makes you a red-head; even
more brown-haired; and even more, hair that looks blue-black. Pretty remarkable, huh?
What do goosebumps have to do with hair?
Everything! When you are chilled, or startled, you sometimes develop goosebumps. What are
they? Temporary bumps on your skin caused by muscles attached to hair follicles pulling those hairs
upright! Goosebumps actually serve a purpose in animals. Fluffing up fur or feathers helps trap air
and make them warmer or make them look bigger and scarier. What do goosebumps do for humans? You
tell us.
What does puberty have to do with hair?
As you approach puberty, you are likely to discover that several things about your body --
including patterns of body and facial hair -- are going to change. You'll start developing hairy
underarms, and pubic hair.... If you're a boy, you may find yourself wanting to shave the hair on
your upper lip and on your chin; if you're a girl, you may have hairy legs for the first time in
your life. Puberty makes life interesting, eh?
FACTOIDS:
- Generally about 80 hairs are likely to fall out every day.
- But don't worry. You probably have about 100,000 hair follicles on your head!
- Even where you don't see hairs on your body, you've got them -- some 5 million of them!
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