1. The largest cell in the human body is the female egg cell; the smallest is the male sperm cell.
2. The brain is much more active at night than during the day.
3. During your lifetime, a person produces enough saliva to fill two large Olympic swimming pools.
4. Your nose can remember 50,000 different smells.
5. A woman's heart beats faster than a man's.
6. Your eyes remain the same size from birth to death, but your nose and ears never stop growing.
7. Every single day, there are 120 million instances of sexual intercourse on Earth.
8. The brain itself cannot feel pain.
9. The largest internal organ is the small intestine.
10. A sneeze typically exceeds 160 km/h, and nerve impulses to and from the brain travel at approximately 270 km/h.
11. It takes 17 muscles to smile, 43 to frown, and 3 muscles to hit someone.
12. Relative to its size, the tongue is the strongest muscle in the body.
13. One can literally die of a “broken heart”;
this is called “ broken heart syndrome ”.
14. The hyoid bone is the only bone in the human body that is not connected to another bone.
15. The skin on the fingers does not wrinkle in water because it absorbs the water or because the water washes away the skin's natural oils, but because of an evolutionary behavior, as the brain tries to improve grip strength underwater.