11,000 liters of air per day pass through our lungs. At the same time, our heart contracts and pumps around 100,000 times a day, moving 12,000 liters of blood through 1,600 km of veins. If the body is healthy, we hardly notice these operations. It certainly helps that we spend about 24 years of our lives sleeping ...
Our body in figures- if we start at the top: on our heads we can find up to 150,000 hairs, each of which grows about 0.3 millimeters a day. These hairs can be up to seven years old. If we never cut them, they would be almost 10 meters long after an average of 80 years. Incidentally, our nails would have grown to about 28 meters by then. Eww!
Under the hair on our heads, in our walnut-shaped brains, there are 100 billion nerve cells that are responsible for, among other things, the 10,000 different smells and tastes we experience. Concerning tastes, there are five tastes we can perceive: sweet, sour, salty, umami and bitter tastes. From a broader perspective, if we were to line up all the cells in the body, this would result in a chain that would reach around the equator about 50 times (100 trillion cells).
Enveloping the whole body is the greatest of all the organs: the skin, which weighs up to 10 pounds, covers 2 square meters and is renewed from the surface up every 120 days. Holding everything together are 212 bones, the smallest of which is the 3mm long stirrups, (the third bone in the middle ear), the largest of which is the hip bone and the longest of which is found in the thigh. There are also 656 muscles, 400 tendons, and countless amounts of cartilage.The largest muscle in our bodies is our gluteus maximus, ie the behind.
To ensure that all of these things continue working, we ingest some 30,000 kilograms of food over a lifetime, an achievement for which we would need approximately 3.5 years, if we wanted to eat it all at once. The 71,000 liters of liquid we drink over our lives comes to about 300 bathtubs full of water. This water helps power the 50 million steps we take in our lifetimes, steps which cover almost 100,000 kilometers - as far as two and a half times around the globe! On the same globe there are currently just under 7.3 billion people. By the year 2050, there are predicted to be 9.6 billion - we'll just have to see!
Taking in this lovely view, we have two eyes weighing 7.5 grams and containing 132 million photoreceptor cells. These cells can process approximately 35,000 images per hour. Interestingly, the proportion of blue-eyed people, currently around ten percent of the world's population, will decline by the year 2050. Incidentally, the population demographics will also change dramatically in the year 2050 - out of every 100 terrestrials, only ten will be Europeans, 34 will be Africans and 74 will be Asians, increasing the chances of the world's population having brown eyes.