Aging & Altered Cellular and Tissue Biology
- It is difficult to determine the physiologic (normal) from the pathologic changes of aging.
- Humans have an inherent maximal life span (80 to 100 years) that is dictated by currently unknown intrinsic mechanisms.
- Although the maximal life span has not changed significantly over time, the average life span, or life expectancy, has increased. Life expectancy for men is about 75 years, and for women it is 80 years.
- The physiologic mechanisms of aging apparently are associated with (a) cellular changes produced by genetic and environmental-lifestyle factors, (b) changes in cellular regulatory or control mechanisms, and (c) degenerative extracellular and vascular alterations.
- Frailty is imprecisely defined as a wasting syndrome of aging leaving a person vulnerable to falls, functional decline, disease, and death.