The Somatic Mutation Theory of Aging is one of several well developed theories that attempt to explain why human bodies age. Logically, it does not make sense that the same body that produces billions of cells from the age of 0 to about 27 suddenly begins to loose the ability to produce new cells that are as vital and strong as they have always been. The mechanism of reproduction does not change. The general cellular structure does not change. For the most part, the vast majority of your cells continue to do this quite well for another 20 or 30 years. But, everyone eventually knows that the aging process catches up with them.
The Somatic Mutation Theory of Aging tries to explain why healthy cells suddenly begin to produce unhealthy cells.
The simple idea behind a complex theory is that with the tens of thousands of genes that are reproduced every time a cell in your body divides to make a new cell, an occasional error happens. Most of these incorrectly copied genes never create any problems. However, without being repaired, later copies make the problem worse. Eventually, the line of cells coming from the errant copy no longer quite function like the original cell. This process happens over and over and over during a span of several decades until enough poorly functioning cells are present to cause changes in the tissue that they comprise. The outcome is called aging.
When a new cell is different from the parent cell, it is called a mutation.
With comic books and movies like the X-Men, people tend to view a mutation as a new and superior life form. However, almost all mutations change the cell or organism downward rather than upward. This means that in nearly every case, when a cell mutates, the copy is not as good as the original. Once the step downward occurs, it is all but impossible to reverse. People try to do this artificially with vitamins, skin creams, and plastic surgery. All of these techniques only mask the marching of aging.
Somatic Mutation occurs when any cell that does not produce a sperm or an egg divides.
This could be a skin cell, liver cell, stomach cell, or almost any other cell in your body. Because people tend to live longer today than they have lived historically, more of the aging process becomes visible. Wrinkles and lines are indicators that lower quality skin cells are being produced in higher quantities. Because the skin is exposed to more destructive environmental factors than the internal organs, it shows the effects of the somatic mutation sooner.
If a person lives long enough, all bodily organs and tissues begin to display the aging caused by somatic mutation.
As people live beyond 90 and 100 years, more of them die from multiple organ failure due to aging. The lungs, heart, liver, kidneys, muscles, and every other organ suffers from the effects of long term somatic mutation. Just as the skin sags and wrinkles, the other organs have their way of showing the loss of function from aging. Kidneys either quit working altogether or they dump more than necessary of the bodies nutrients into the urine. Lungs loose their elasticity and fill with fluid. The heart becomes weaker and cannot maintain adequate blood pressure to keep other organs functioning correctly. The list goes on.
Weakness in one area can accelerate the somatic mutation process in other organs.
Weak lungs put pressure on the heart. This causes an aging heart to attempt to build itself bigger and stronger and in so doing, it produces more mutated cells. The same scenario can play out throughout the body until the mutations become some prevalent that survival is impossible.
Reference:
http://longevity.about.com/od/longevity101/a/why_we_age.htm
