Physiology
Blood Vessels Circle The Earth
Laid end to end, an adult's blood vessels would stretch around 100,000 km, more than twice around the Earth.
More in Physiology
Babies Have More Bones
Babies are born with around 300 bones; many fuse as they grow, leaving adults with 206.
Your Eyes Can See Millions Of Colours
The human eye can tell apart around a million colours using just three kinds of cone cells.
100,000 Beats A Day
Your heart beats about 100,000 times a day, pumping roughly 7,500 litres of blood around your body.
The Liver Grows Back
The liver can regrow to full size even after much of it is removed, the only organ able to regenerate like that.
A Tennis Court In Your Chest
Spread flat, the tiny air sacs in your lungs would cover roughly half a tennis court.
Over 600 Muscles
The human body has more than 600 muscles, and even a simple smile uses around a dozen of them.