1. The stomach’s digestive acids are strong enough to dissolve zinc. Fortunately for us, the cells in the stomach lining renew so quickly that the acids don’t have time to dissolve it.
2. The lungs contain over 300,000 million capillaries (tiny blood vessels). If they were laid end to end, they would stretch 2400km (1500 miles).
3. A man’s testicles manufacture 10 million new sperm cells each day – enough that he could repopulate the entire planet in only 6 months!
4. Human bone is as strong as granite in supporting weight. A block of bone the size of a matchbox can support 9 tonnes – that is four times as much as concrete can support.
5. Each finger and toenail takes six months to grow from base to tip.
6. The largest organ in the body is the skin. In an adult man it covers about 1.9 square metres (20sq ft). The skin constantly flakes away – in a lifetime each person sheds around 18kg (40 lb) of skin.
7. When you sleep, you grow by about 8mm (0.3in). The next day you shrink back to your former height. The reason is that your cartilage discs are squeezed like sponges by the force of gravity when you stand or sit.
8. The average person in the west eats 50 tonnes of food and drinks 50,000 litres (11,000 gallons) of liquid during their life.
9. Each kidney contains 1 million individual filters. They filter an average of around 1.3 litres (2.2 pints) of blood per minute and expel up to 1.4 litres (2.5 pints) a day of urine.
10. The focusing muscles of the eyes move around 100,000 times a day. To give your leg muscles the same workout, you would need to walk 80km (50 miles) every day.
11. In 30 minutes, the average body gives off enough heat (combined) to bring a half gallon of water to boil.
12. A single human blood cell takes only 60 seconds to make a complete circuit of the body.
13. A foreskin, the size of a postage stamp, from circumcised babies take only 21 days to grow skin that can cover three basketball courts. Amazing isn’t it? Thanks to science, the laboratory-grown skin is used in treating burn patients.
14. The eyes receive approximately 90 percent of all our information, making us basically visual creatures.
15. The female ovaries contain nearly half-a-million egg cells, yet only 400 or so will ever get the opportunity to create a new life.