We tend to think that we know our own bodies perfectly. We know how they work and what kinds of changes and processes are occurring in them every second of the day. But in fact, the human body is one seriously complex and mysterious mechanism that sometimes confuses even the most qualified specialists — doctors and scientists.

1. The cornea is the only part of the body with no blood supply – it gets its oxygen directly from the air.

2. The human body contains enough fat to make seven bars of soap.

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3. Embryos develop fingerprints three months after conception.

4. Between birth and death, the human body goes from having 300 bones, to just 206.

5. Hearts can beat outside of their bodies.

6. When you blush, the inside of your stomach does too.

7. Humans have a “diving reflex” that shuts down bodily functions when submerged in water to prevent drowning.

8. There are certain kinds of tumors that can grow their own teeth and hair – they’re called teratomas.

9. Humans are bioluminescent, the light just isn’t perceptible to the human eye.

10. Astronauts can grow up to two inches taller in space.

11. Your brain can survive for five to 10 minutes without oxygen.

12. In cases of extreme starvation, the brain will begin to eat itself.

13. When listening to music, your heartbeat will sync with the rhythm.

14. The small intestine is roughly 23 feet long.

15. One quarter of your bones are in your feet.

16. Every organ you have two of, you only need one of to survive.

17. There are more than 100,000 miles of blood vessels in your body.

18. You are taller in the morning than you are at night.

19. You can’t breathe and swallow at the same time.

20. Your left kidney is higher up than your right kidney.

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