The areas of the tongue sensitive to tastes. The classical theory about the physiology of taste recognizes the existence of four fundamental tastes - sweet, salty, sour and bitter - each being perceived by specific areas of the tongue by means of gustatory receptors, also known as taste buds.
Theories of Aging. Theories of Aging. Erik Erikson, who took a special interest in this final stage of life, concluded that the primary psychosocial task of late adulthood (65 and beyond) is to maintain ego integrity (holding on to one's sense of wholeness), while avoiding despair (fearing there is too little time to begin a new life course).
Ageing is a universal, intrinsic, progressive and deleterious process. Understanding it is of major interest to scientist, physicians as well as to the general population. Critical to this understanding is to formulate comprehensive theories of aging with high predictive and explanatory power.More than 300 theories have been postulated and are reviewed here. The free radical theory of ageing is one of the most prominent and well studied.It was further developed by one of us (JM) in what has become known as the mitochondrial theory of ageing. These theories provide new experimental approaches to further develop our understanding of the phenomenon of ageing.ritical to this understanding is to formulate comprehensive theories of aging with high predictive and explanatory power. More than 300 theories have been postulated and are reviewed here. The free radical theory of ageing is one of the most prominent and well studied.