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Body Chemistry

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For a proper understanding of how all body functions, including sexual function, can be modified by pharmaceutical (which is: chemical) methods, it is necessary to have an idea on how the human body is organized on the chemical level. This article reviews the basics of the chemical organization of the human body. To read it (from the beginning), no prior knowledge of chemistry, biology, or human anatomy and physiology) is needed.

While 92 chemical elements occur naturally on earth (and while another 20 have been created in laboratories), the human body is built of only 26 elements. Of these, only 4 elements (oxygen, hydrogen, carbon, nitrogen) constitute 96 % of human body mass. Another 8 (calcium, phosphorus, potassium, sulfur, sodium, chlorine, magnesium, and iron) account for another 3.8 %. The remaining 0.2 % is used by 14 trace elements. Oxygen alone is 65 % of body mass; carbon is 18.5 %, hydrogen 9.5 %, nitrogen 3.2 %.

An element is a substance that consists of just one kind of atoms. The smallest atom is the hydrogen atom, with a diameter of just 10-10 m. Chemistry as a science organizes chemical elements in the periodic table. If read from left to right, line after line, the elements are arranged in accordance to a sequence of atomic numbers, from 1 (hydrogen) to 112 (which is still unnamed). The atomic number corresponds to number of protons in the nucleus of the atom of a specific element. Another number that is assigned is the mass number, which corresponds to the number of protons plus the number of neutron. Atoms with the same atomic number, but a different mass number, are isotopes.

Atomic mass is measured in daltons. 1 dalton = 1 atomic mass unit (amu). 1 proton = 1.007 daltons. 1 electron = 0.0005 daltons. The mass of an electron is about 2000 times smaller than that of a proton or neutron. A typical periodic table lists the atomic mass of each element as the average of the prevalence of naturally occurring isotopes. For example, the atomic mass of chlorine is 35.45 daltons.

Free radicals are atoms or groups of atoms with unpaired electrons in its outermost shell. Exposure to sunlight or UV or x-ray radiation generates free radicals. A common free radical is the superoxide free radical, O2- (a oxygen molecule,O2, that has picked up one additional electron). Free radicals are highly damaging to tissue, as they are very reactive and therefore can destroy cells. Antioxidants that can counteract this are: selenium, beta-carotine, vitamin C and vitamin E. That the chemical element selenium, for example, works as an antioxidant doesn't mean that one would have to buy selenium supplements. The best natural souce of selenium are paranuts.

Diseases caused by free radicals include cancer, atherosclerosis, Alzheimer's, emphysema, diabetes mellitus, cataracts, macular degeneration, rheumatoid arthritis, and aging-related deterioration.

Chemical bonds

There are three classes of chemical bonds: ionic, covalent, hydrogen bonds.

Ionic compounds usually exist as solids (crystals). When an ionic compound is dissolved as positive and negative ions, it forms an electrolyte.

In polar covalent bonds, the shared electrons are more strongly attracted by one of the elements in the covalent bond. Oxygen and hydrogen form water molecules, which are highly polar.

Hydrogen bonds are only 5 % as strong as typical covalent bonds.