The human body is a fabulously efficient machine with a carefully balanced, perfectly designed chemistry. The sheer scale and intricate design of the ‘machine’ is awe inspiring. Things are going on within our bodies at a terrific speed and on a huge scale, yet we are mostly unaware of it.
If you take the height of a child on his or her second birthday, and double it, you will get a good estimate of the final adult height. A boy, aged two is around 49.5% of his adult height and a girl at the same age is 52.8% of her adult height.
The human brain is about 3% of the total body weight of the average human being but it uses 20% of all the oxygen we breathe in, 20 per cent of the calories in the food consumed and 15% of the body’s blood supply. It is power hungry and very heavy on resources.
An adult human has 650 different muscles, 100 joints, 100,000 kilometers of blood vessels and 13,000 million nerve cells. There are 206 bones with most of them in the hands and feet. At birth a baby has 300 bones but 94 of these fuse together during the early years.
The heart beats over 2000 million times during an average human life span and pumps more than 500 million liters of blood. Even during sleep the small, fist sized heart continues to pump at a rate of approximately 340 liters per hour. Just imagine filling an average car’s fuel tank every seven minutes and that is what the human heart is capable of. The muscle power is huge.
The acids which digest food in the stomach are strong enough to dissolve zinc. The cells in the stomach are replaced at the rate of 500,000 per minute and a brand new lining is formed every three days, so the acid doesn’t get the chance to dissolve the lining.
A human kidney has a million individual filters and a pair of kidneys can filter 1.3 liters of blood every minute. The waste that is removed is expelled as urine at about 1.4 liters per day.
The body’s complete blood supply runs through the lungs every minute. The red corpuscles in the blood are made in the bone marrow at the huge rate of 1.2 million corpuscles per second. Each one of these lives for about four months and in a human life time, the bone marrow manufactures around half a ton of red corpuscles.
The largest organ is the skin and in an adult male it covers around 1.9 square meters. (1.6 square meters in a woman.) It constantly flakes away and is completely replaced once every fifty days. On average approximately 18 kilograms of skin is shed in a life time.
What an amazing machine!
Bibliography
