How many kilometres of veins, arteries and capillaries does a human have?

Explanation

A human has around 1.8 m² skin, around 600 muscles and 206 bones, more than 100 joints, 90,000 km veins, arteries and capillaries as well as 13 billion nerve cells. Every minute 4-6 litres of blood are pumped through the heart. A human has some 25 billion red, round blood cells, each with a diameter of 0.007 mm. The total surface amounts to 1,300 m². A brain weighs an average of 1,350. Although the human brain is large, it is not the biggest amongst animals. Both elephants and whales have significantly larger brains.