GRT 2111 Lecture Notes - Lipofuscin, Osteoarthritis, P53
9 Feb 2013
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Document Summary
Changes in multiple physiological systems cancer atherosclerosis osteoporosis osteoarthritis skin aging immune senescence. Accidental theories of aging (a. k. a. stochastic theories): aging is caused by a series of adverse events in cells that lead to replicative errors. Programmed-aging theories (a. k. a. non-stochastic theories): intrinsic & predetermined /programmed changes in cells. Accumulation of normal injury due to continued use. Our bodies repair themselves, replace lost cells & damaged proteins, make new mitochondria and molecules, fix dna, etc Mutations occur in cells (soma) due to repeated replication, exposure to toxins, radiation or ultraviolet light. The body cannot correct/destroy all mutations, but not all of them, and eventually the mutated cells accumulate. Aging is caused by cumulative errors in dna/rna. Free radicals are chemical byproducts of normal cell metabolism involving oxygen. Proteins (e. g. , collagen, elastin) become cross-linked and thus less flexible. Aging is caused by the accumulation of substances in cells.
