Why Do We Have Hair?
Hats off to hair (pun intended), which keeps you warm and protects your skin.
But what’s the science behind hair? What parts does it have? How does it grow? What is its favorite color?
Hair has two sections. The shy little follicle hides under the skin, while the brash, gaudy shaft struts its stuff on top. The follicle is a burrow for the living part of your hair: the bulb. The cells of the bulb are regular speed demons, reproducing faster than any other cells in your body. It takes only 23 to 72 hours for them to divide. That’s why you can get your hair cut, and four weeks later your bangs are already in your eyes. Blood vessels at the bottom of follicles nourish the bulbs.
You know how you brush your hair to make it shiny? (No? Well, some people do; you’ve seen them.) The shaft of your hair, which is composed of the protein keratin, is actually dead. Dead, dead, dead. Doornail dead. Deader than a zombie. You’re brushing dead cells. What are you thinking?
A shaft has three layers, but only the innermost two layers contain the pigment melanin that gives hair its lovely color. What do you call that on your head? Golden walnut? Buttered toast? Glazed strawberry? Oh. Brown.
You start out with about 5 million hairs on your body, and at least 100,000 of these make up your head of hair. (Oh, careful, you just pulled one out…99,999 left.) Scalp hair grows, on average, 6 inches per year. Hair grows in phases, and the hair on your head has a much longer growing season than, say, the hair on your arms, eyelashes, or eyebrows. Lucky for that…who’d want to braid their eyelashes? Hair growth varies so much from person to person. Some people never seem to be able to grow their hair very long. That’s because their active growing phase is short. Rapunzel, on the other hand, has MAD growing phases. You go, girl!
If you love hair, here’s a blast from the past:http://www.youtube.com/watch?v=BFy-yzj02FE