The only time most of us think about our blood is when we cut ourselves and start bleeding. But blood is a remarkable substance that we truly could not live without. Consider some of these facts about blood we take for granted.

1. Nearly 1.5 million barrels of blood will be pumped by your heart during your lifetime, enough to fill 200 train tank cars.
2. One pint of donated blood can save up to three lives.
3. Someone in the U.S. needs blood every two seconds.
4. There are 100,000 miles of blood vessels in an adult human body.
5. A red blood cell can make a complete circuit of your body in 30 seconds.
6. Our bodies contain about 0.2 milligrams of gold, most of it in our blood.
7. Eight percent of your body weight is your blood.
8. There are 150 billion red blood cells in one ounce of blood and 2.4 trillion of these cells in one pint of blood.
9. The human body manufactures 17 million red blood cells per second. If stressed, the body can produce up to seven times that amount, or 119 million red blood cells per second.
10. All blood isn’t red. Crabs have blue blood. Earthworms and leeches have green blood. Many invertebrates like starfish have clear or yellowish blood.

Source: FactSlides.com