1. Approximately 50,000 cells in your body will die and be replaced with new cells during the time it takes you to read this sentence. We make a new skeleton every three months and a new layer of skin every month.
2. There's something unique about all of us, and it's not just your fingerprint. Every human has a unique tongue print, too.
3. Every square inch of your skin contains 20 feet of blood vessels, 4 yards of nerve fibers, 1,300 nerve cells, 100 sweat glands, and 3 million cells.
4. In one hour, your heart produces enough energy to raise a ton of steel 3 feet off the ground.
5. You use an average of 43 muscles in your face when you frown. It only takes 17 muscles to smile.
6. Red blood cells are frequent fliers. After being created inside the bones, the cells make approximately 250,000 round trips -- at 60,000 miles each trip-- through the body before returning to the bone marrow to die 120 days later.
7. The adult human body comprises 206 bones, and more than half are accounted for in the hands and feet.
8. The heart will beat an average of 3 billion times during an average person's lifetime.
9. The aorta is the large artery that runs down the center of your body. It's almost the diameter of a garden hose. By contrast, capillaries, the body's smallest blood vessels, are so small that it takes 10 of them side by side to equal the thickness of one strand of human hair.
10. The average person will lose 100 strands of hair per day and over 10 billion skin flakes. Get out the vacuum!
11. The human eye can distinguish up to a million different colors and take in more information than the largest telescope known to man.
12. When we touch something, the signal travels through the nerves to our brain at a speed of 124 mph.
13. The skin is the body's largest organ, but it's also a pretty big medicine cabinet. The skin secretes antibacterial substances and serves as the first layer of defense for invading microorganisms. Most bacteria that land on the skin die quickly.
14. An adult stomach can hold up to 1.5 liters of material, but this doesn't mean you have to test that limit at every meal.
15. Fingernails and hair are made out of the same substance -- keratin.
16. During the first month of life, an infant is learning so many new things that the number of connections, called synapses, between brain cells increases from 50 trillion to 1 quadrillion. By comparison, if the rest of the infant's body responded with equally rapid growth, she'd weigh 170 pounds by the time she was a month old.
17. If the shoe fits...well, just make sure it does. The big toe is one of the most important structural parts of the body. That one appendage is responsible for helping us maintain our balance and propel us forward when walking .
18. The human liver is responsible for more than 500 distinct processes in the body. It is so important that if a person has two-thirds of their liver removed as a result of trauma or surgery, it will grow back to its original size in as little as four weeks.
19. Beards are the fastest growing hairs on the human body. If the average man never trimmed his beard, it would grow to nearly 30 feet long in his lifetime.
20. The average person takes 23,000 breaths a day. Make this one count.