– Organismal senescence:
– Refers to the aging of whole organisms.
– Actuarial senescence involves increased mortality and decreased fecundity with age.
– The Gompertz–Makeham law states that mortality rate increases exponentially with age.
– Aging is marked by reduced ability to handle stress and increased risk of diseases like cancer and heart disease.
– Defined as a progressive decline in physiological function and increased vulnerability.
– Cellular senescence:
– Involves cells ceasing to divide.
– Can be induced by factors like DNA damage or shortening of telomeres.
– Senescent cells can affect neighboring cells through a phenomenon called senescence-associated secretory phenotype.
– Cellular senescence plays a role in aging and age-related diseases.
– Research is ongoing to understand and manipulate cellular senescence for potential therapeutic benefits.
– Factors influencing senescence:
– Environmental factors like ultraviolet radiation can accelerate aging.
– Different body parts age at varying rates, affecting functions like movement control and memory.
– Biological aging and chronological aging can differ, causing variations in aging rates among individuals.
– Calorie restriction has been shown to extend lifespans in certain organisms.
– Some species exhibit negligible senescence, inspiring research into delaying aging and age-related diseases.
– Delaying senescence:
– Discoveries like calorie restriction extending lifespans in rats have spurred research into delaying senescence.
– Species like Hydra show potential immortality, leading to investigations on delaying aging.
– Rare human mutations can cause accelerated aging diseases.
– Understanding the mechanisms of senescence can help in developing interventions to delay aging effects.
– Strategies to delay senescence may offer insights into combating age-related diseases.
– Impact of senescence on different systems:
– Aging affects various body systems differently, including the brain, cardiovascular system, and muscles.
– Overexposure to environmental factors can accelerate aging, such as skin aging due to ultraviolet radiation.
– Functions like movement control and memory can decline with age.
– The concept of biological aging differs from chronological aging, leading to variations in aging rates among individuals of the same species.
– Understanding the impact of senescence on different systems can aid in developing targeted interventions for age-related conditions.
Senescence (/sɪˈnɛsəns/) or biological aging is the gradual deterioration of functional characteristics in living organisms. The word senescence can refer to either cellular senescence or to senescence of the whole organism. Organismal senescence involves an increase in death rates and/or a decrease in fecundity with increasing age, at least in the later part of an organism's life cycle. However, the resulting effects of senescence can be delayed. The 1934 discovery that calorie restriction can extend lifespans by 50% in rats, the existence of species having negligible senescence, and the existence of potentially immortal organisms such as members of the genus Hydra have motivated research into delaying senescence and thus age-related diseases. Rare human mutations can cause accelerated aging diseases.
Environmental factors may affect aging – for example, overexposure to ultraviolet radiation accelerates skin aging. Different parts of the body may age at different rates and distinctly, including the brain, the cardiovascular system, and muscle. Similarly, functions may distinctly decline with aging, including movement control and memory. Two organisms of the same species can also age at different rates, making biological aging and chronological aging distinct concepts.