physiology of egeing Flashcards
What is ageing?
Ageing is a (near) universal, intrinsic, progressive, and deleterious process characterized by a measurable reduction in reproductive capability, functional decline (both physical and cognitive), and rising death rates with age.
How is ageing normally characterized?
Ageing is normally characterized by a measurable reduction in reproductive capability, functional decline (both physical and cognitive), and rising death rates with age.
What is the relationship between mortality rate and age in the context of ageing?
In the context of ageing, there is a correlation between increasing mortality rates and advancing age. As individuals age, the risk of death rises.
Is ageing genetic?
es, ageing has a genetic component.
Explanation: The heritability of lifespan is estimated to be around 16%, indicating that genetics play a role in determining how long an individual lives. Moreover, age-related diseases have a higher heritability, reaching up to almost 80% in some cases. Parental lifespan is also considered an important predictor of an individual’s lifespan.
What are some systemwide characteristics associated with ageing?
Ageing is associated with several systemwide characteristics, including decreased force and elasticity of the skeletal muscular system, lower filtration rates in the kidneys, lower pulmonary ventilation, lower maximal blood flow through the heart, glucose intolerance, atrophy or degeneration of most organs, and degradation of intercellular matter.
Are there any identified genetic variants associated with lifespan?
Yes, some lifespan-associated genetic variants have been detected, although analyzing them is complex.
What happens to skeletal muscle with ageing?
With ageing, skeletal muscle experiences a loss of mass and reduced function. This condition is known as sarcopenia, which primarily affects the elderly. Sarcopenia leads to a loss of strength, increased likelihood of falls, and a loss of autonomy.
How does the lung change with ageing?
With ageing, the lung undergoes a loss of elastic recoil, dilatation of the alveoli, and a loss of supporting structures for the peripheral airways. These changes result in increased residual volume and age-related declines in forced vital capacity and forced expiratory volume.
What is organ reserve?
Organ reserve refers to the ability of an organ to endure periods of physiological stress and restore to nominal function after such a period. However, this reserve declines with age.
What are some cellular and molecular characteristics of ageing?
Some cellular and molecular characteristics of ageing include stem cell exhaustion, mitochondrial dysfunction leading to reduced energy outputs, increased levels of oxidative stress, altered intercellular communications, and deregulated nutrient sensing.
What are some cellular and molecular characteristics of ageing related to genomic instability?
Genomic instability, especially DNA damage, telomere attrition, epigenetic alterations, changes in gene expression, and loss of protein homeostasis, are among the cellular and molecular characteristics associated with ageing.
How does cellular damage increase with age?
Cellular damage increases with age across various classes of molecules and processes. Some examples include transcription errors in RNA, post-translational modifications in proteins, structural damage and mutations in DNA, epigenetic alterations such as histone modifications and chromatin remodeling, and decreased clearance of damaged molecules due to autophagy failure.
What is cellular senescence?
Cellular senescence is a phenomenon first described in 1961, where it was observed that cultured fibroblasts had a limited number of divisions. Cells in vitro become arrested in a phase known as replicative senescence. As we age, more cells enter senescence. It may account for tissue aging, although senescence can also protect against cancer.
What is telomere attrition?
Telomere attrition refers to the reduction in length of telomeres, which are protective caps at the ends of chromosomes, with each cell division. Telomere shortening induces cellular senescence in a manner similar to DNA damage.
What are epigenetic changes in aging cells?
Epigenetic changes in aging cells refer to alterations in the structure of chromatin and chemical modifications of DNA, such as methylation. The progressive accumulation of age-associated epigenetic changes can lead to altered gene expression, loss of gene expression control, changes in cellular metabolism, and cellular senescence.
