Senescence

Senescence (from Latin: senescere, meaning “to grow old,” from senex) or biological aging is the endogenous and hereditary process of accumulative changes to molecular and cellular structure disrupting metabolism with the passage of time, resulting in deterioration and death. Senescence occurs both on the level of the whole organism (organismal senescence) as well as on the level of its individual cells (cellular senescence). The science of biological aging is biogerontology.