Urinary System 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. It's a body protein called keratin and it grows out of a minuscule opening of the skin called a follicle. 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. When you are chilled, or startled, you sometimes develop goosebumps. 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.