WHAT has nine feet of blood vessels, 600 pain sensors, 30 hairs, 13 yards of nerves, 9,000 nerve endings, 36 heat sensors and 75 pressure sensors per square inch? No, it's not the creature from outer space, but something far more mundane and closer to home. It's your hand - just one example of how little we know about our bodies and how much we take them for granted.
In fact, when you look in the mirror what you see is the most advanced form of engineering in the world. What allows you to see that image in the mirror is light bouncing on 14 million cones in your eyes and 200 million tiny rods sending electrical impulses via your optic nerve to your brain.
Every day your heart beats 100,000 times and your skin renews itself, and in the same 24 hours you give birth to 100 billion red blood cells.
As you walk across the room you exercise more than 250 muscles and when you touch something you send a message to your brain at over 200 kilometres an hour.
Your body also has an army of complicated and highly efficient infection-fighters which work constantly to destroy invading viruses and bacteria, while it has astonishing powers of regeneration following serious illness, major surgery or trauma.
You should now be convinced that your body is an amazing feat of engineering, but to stay in perfect working order it needs a bit of help.
