New elements in modern biological theories of aging

Abstract

Generally and simply speaking, when human individuals think of how their bodies are aging, probably the most visible changes come first to their minds. One can notice more grey hair or the skin does not seem as smooth as it used to be. These are just external signs of a series of processes going on within our cells and bodily systems that together constitute normal aging. Aging (also called senescence) is an age-dependent decline in physiological function, demographically manifesting as decreased survival and fecundity with increasing age. Aging is also commonly defined as the accumulation of diverse deleterious changes occurring in cells and tissues with advancing age that are responsible for the increased risk of disease and death. The principal theories of aging are all specific of a distinct cause of aging, giving useful and deep insights for the understanding of age-related physiological changes.