Page 115 - The Cell in 40 Topics

itric oxide (NO) is a colorless, but toxic gas obtained by the
oxidization of nitrogen—a molecule formed by the combi-
nation of one nitrogen and one oxygen atom. Despite its
toxicity, this molecule has an attribute of the greatest importance for
human life. Over the last 20 years, intense research has revealed that this
molecule undertakes a fundamental task in communication among cells.
Results of this scientific endeavor have shown that nitric oxide is a hor-
mone produced naturally in the human body, as yet another chemical mes-
senger that plays a strategic role in the regulation of functions in the
nervous, circulatory, immune, respiratory and reproductive systems.
One location where NO undertakes a most important duty is in the
veins. The internal diameter of the veins is not fixed, but expands and con-
tracts according to our activities, thus playing an important role in regulat-
ing our blood pressure. Thanks to this immaculate system, the body’s
needs are met, even while vary according to the surrounding environment.
When you play sports, your blood vessels expand to supply the increasing
demand for blood flow; and following injury they contract, reducing possi-
ble blood loss—all as a result of the ideal system in question.

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