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The metabolic stability theory of aging suggests it is the cells ability to maintain stable concentration of ROS which is the primary determinant of lifespan. [37] This theory criticizes the free radical theory because it ignores that ROS are specific signalling molecules which are necessary for maintaining normal cell functions. [37]
The mitochondrial theory of ageing has two varieties: free radical and non-free radical. The first is one of the variants of the free radical theory of ageing. It was formulated by J. Miquel and colleagues in 1980 [1] and was developed in the works of Linnane and coworkers (1989). [2] The second was proposed by A. N. Lobachev in 1978. [3]
The somatic mutation theory of ageing states that accumulation of mutations in somatic cells is the primary cause of aging. A comparison of somatic mutation rate across several mammal species found that the total number of accumulated mutations at the end of lifespan was roughly equal across a broad range of lifespans. [ 16 ]
All evolutionary theories of aging rest on the basic mechanisms that the force of natural selection declines with age. [19] [20] Mechanistic theories of aging can be divided into theories that propose aging is programmed, and damage accumulation theories, i.e. those that propose aging to be caused by specific molecular changes occurring over time.
These stress factors include both environmental and internal damaging events, abnormal cellular growth, oxidative stress, autophagy factors, among many other things. [8] The physiological importance for cell senescence has been attributed to prevention of carcinogenesis, and more recently, aging, development, and tissue repair. [9]
Selectivity theory (aging) Socioemotional selectivity theory; Stage-crisis view; Stem cell theory of aging; Stereotype embodiment theory; T. Telomere theory of aging; V.
Biogerontology should not be confused with geriatrics, which is a field of medicine that studies the treatment of existing disease in aging people, rather than the treatment of aging itself. There are numerous theories of aging, and no one theory has been entirely accepted.
Ageing (or aging in American English) is the process of becoming older. The term refers mainly to humans , many other animals , and fungi, whereas for example, bacteria, perennial plants and some simple animals are potentially biologically immortal .