The passage discusses the role of membrane receptors and transmitter turnover in explaining neuronal reactions and their impact on aging. It highlights that structural and metabolic changes in nerve cells contribute to the aging process by altering neuronal functions. The text also explores the potential redistribution of energy pathways in neuronal function with aging. Additionally, it delves into the genetic aspects of longevity, questioning whether interspecific and intraspecific differences in life spans are genetically determined. The author examines the impact of major and minor genes on longevity, noting that major gene mutations generally shorten lifespan rather than extend it. The study of minor genes with additive action is also discussed, emphasizing the need for a nuanced understanding of polygenic inheritance in aging research.The passage discusses the role of membrane receptors and transmitter turnover in explaining neuronal reactions and their impact on aging. It highlights that structural and metabolic changes in nerve cells contribute to the aging process by altering neuronal functions. The text also explores the potential redistribution of energy pathways in neuronal function with aging. Additionally, it delves into the genetic aspects of longevity, questioning whether interspecific and intraspecific differences in life spans are genetically determined. The author examines the impact of major and minor genes on longevity, noting that major gene mutations generally shorten lifespan rather than extend it. The study of minor genes with additive action is also discussed, emphasizing the need for a nuanced understanding of polygenic inheritance in aging research.