How hair grows (From American Academy of Dermatology http://www.aad.org/)

An illustration of hair follicles on skin.

Hair grows out of little pockets in your skin, called follicles. Here's how it happens:

1. Your hair begins growing from a root in the bottom of the follicle.The root is made up of cells of protein.

2. Blood from the blood vessels in your scalp feeds the root, which creates more cells and makes the hair grow.

3. The hair gets pushed up through the skin as it grows, passing an oil gland along the way. The oil gland adds oil to the hair and keeps it shiny and soft. It can make it greasy, too. That's why you need to wash your hair.

4. The hair dies by the time it is long enough to poke out through the skin. Yes, hair is dead. That's why it doesn't hurt to get a haircut.                             


Hair on the rest of your body goes through this same process, but the whole cycle only lasts for a month or so. That's why body hair does not grow very long in length like the hair on your head does.

Info and picture source: http://www.aad.org/dermatology-a-to-z/for-kids/about-hair/how-hair-grows