Saturday, 9 May 2015

Human Body


From: Syed Haq

Almost 99% of the mass of the human body is made up of six elements: oxygen, carbon, hydrogen, nitrogen, calcium, and phosphorus. Only about 0.85% is composed of another five elements: potassium, sulfur, sodium, chlorine, and magnesium. All are necessary to life. The remaining elements are trace elements, of which more than a dozen are thought to be necessary for life, or play a role in good health (e.g., fluorine, which hardens dental enamel but seems to have no other function. An easy way to remember the six most essential elements in living organisms is CHONPC (carbon, hydrogen, oxygen, nitrogen, phosphorus, and calcium). A human cell has a huge number of atoms Human cells are of different sizes and are growing and dividing all the time. According to an estimate made by engineers at Washington University, there are around 10 to power 14 atoms in a typical human cell. Another way of looking at it is that this is 100,000,000,000,000 or 100 trillion atoms. Interestingly, the number of cells in the human body is estimated to be about the same as the number of atoms in a human cell.

Most of the elements needed for life are relatively common in the Earth's crust. There are exceptions: cobalt for instance makes up only about 25 parts per million of the Earth's crust but is essential for human life. Conversely most of the common elements are necessary for life. An exception is aluminum, which is the third most common element in the Earth's crust (after oxygen and silicon), but seems to serve no function in living cells. Rather, it is harmful in large amounts.Transferrins can bind aluminum.

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