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The Facts about Ultra Violet Radiation |
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Understanding the Ultraviolet connection to Skin Cancer
The most dangerous parts of sunlight are the waves in the high-energy ultraviolet (UV) region.
These come in three types, ranging from low to high energy: UV-A, UV-B, and UV-C. as can be seen in the chart above.
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| UV-B causes most sunburns and, experts think, most skin cancers. Some UV-B is partly absorbed by high-altitude ozone. It is blocked by window glass, most sunglasses, and (to varying degrees) sunscreens. A few insidious rays, however, penetrate the top layer of skin and cause aging, immune-system damage and cancer. |
| UV-C are entirely absorbed by ozone molecules in the atmosphere. |
As you can see, most of the concern focuses on UV-B. These rays penetrate the epidermis (the top layer) and damage cells. If UV-B passes through a cell nucleus, it can strike DNA molecules in the chromosomes, breaking them or forming abnormal chemical bonds. In severe cases, entire chromosomes can be reshuffled. Sunlight is most damaging in childhood, when cells are dividing rapidly -- creating opportunities for persistent mutations.
Still, some of the DNA damage that occurs, the body has evolved remarkable mechanisms that constantly monitor and fix DNA, and many of the unrepaired cells commit suicide. However, if that process does not occur and the DNA becomes compromised then it is possible that mutated cells divide without normal limits and controls, quickly developing into Skin Cancer.
Sunlight's ultraviolet radiation strikes where you are most vulnerable: DNA. |
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