ory, belongs to the OCC damage group. This theory holds that senescence results from the slow accumulation of deleterious age pigments. In nondividing cells, such as those of the heart, nerves, and brain, inert substances such as lipofuscin and ceroid are thought to interfere with normal cellular functioning. Eventually, this interference may result in an overall deterioration of the organism. This particular theory, however, does remain unproven. Another OCC damage theory, the "falling domino" theory, also involves the intracellular aging pigments. This hypothesis assumes though, that the accumulations are toxic. After one structure within a cell fails (or "falls"), other structures follow soon thereafter. With a decline in the cells' metabolic and biosynthetic processes, the organism's ability to resist the stress and chronic diseases of old age may be decreased.
A third OCC theory, the "thermal denaturation" theory, states that aging is caused by the slow thermal denaturation of proteins. This process eventually results in death for the involved cells. In fact, cellular loss is considered to be one of the most fundamental causes of human aging
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