Why do our bodies age? - Monica Menesini

00:05:09
https://www.youtube.com/watch?v=GASaqPv0t0g

摘要

TLDRIn 1997, Jeanne Calment became the oldest recorded person, living for 122 years. Aging is a complex biological process characterized by genetic damage, decreased regenerative abilities, and cellular dysfunction. Key mechanisms include mitochondrial decline, telomere shortening, stem cell loss, and changes in cellular communication. Researchers are exploring how diet, exercise, and advanced technologies might affect aging and longevity, raising philosophical questions about the desirability of extended life.

心得

  • 👵 Jeanne Calment lived 122 years, the oldest known person.
  • 🧬 Aging involves genetic damage and cellular decline.
  • ⚡ Mitochondria play a key role in cellular function and energy.
  • ⏳ Telomeres shorten with age, affecting cell replication.
  • 🔬 Stem cells lose regenerative potential as we age.
  • 🧪 Epigenetic changes can lead to degenerative diseases.
  • 🛠️ Future technologies might help extend lifespan.
  • 🥗 Diet and exercise impact aging and health.
  • 🤔 Questions about the desirability of longer life remain.
  • 🔍 The science of aging is still not fully understood.

时间轴

  • 00:00:00 - 00:05:09

    In 1997, Jeanne Calment was recognized as the oldest person in history, living for 122 years. While intriguing, reaching such an age is exceedingly rare for humans, with an approximate biological limit of around 90 years. Aging is a complex process influenced by both internal and external factors, leading to changes at the molecular and cellular levels in the body, ultimately resulting in the decline of function and organism failure. Scientists have identified nine key physiological traits that drive aging, including genetic damage accumulation and mitochondrial dysfunction, which severely impacts cellular energy production. The expression of genes also shifts with age, contributing to degenerative diseases like Alzheimer's. Cellular regeneration diminishes as telomeres shorten with each cell division, leading to senescence. Additionally, the decline in stem cell numbers hampers tissue renewal, and aging cells struggle with quality control over proteins, causing toxic accumulations and impaired intercellular communication. The fundamental question remains: what influences aging, and can future technologies extend human lifespan meaningfully?

思维导图

视频问答

  • Who is Jeanne Calment?

    Jeanne Calment was a French woman who passed away at the age of 122 years and 164 days, making her the oldest known person in history.

  • What are some physiological traits of aging?

    Nine physiological traits of aging include genetic damage, mitochondrial dysfunction, epigenetic alterations, telomere shortening, decreased cell regeneration, senescence, loss of stem cell function, inability to maintain protein quality control, and slow intercellular communication.

  • What is mitochondrial dysfunction?

    Mitochondrial dysfunction refers to the decline in function of mitochondria, leading to reduced energy production and impact on cell activities.

  • How do telomeres affect aging?

    Telomeres shorten with each cell replication, and when they become too short, cells can no longer replicate, leading to decreased tissue regeneration.

  • Can diet and exercise affect aging?

    Yes, diet and exercise are considered factors that can influence the aging process and overall health.

  • What technologies are being researched for extending life?

    Future technologies being researched include cell-repairing nanobots and gene therapy.

  • What happens to stem cells as we age?

    As we age, the number of stem cells decreases, and they lose their ability to regenerate tissues.

  • What are epigenetic alterations?

    Epigenetic alterations are changes in gene expression patterns that can lead to the development of diseases associated with aging.

  • Is longer life desirable?

    The desire for longer life is subjective and varies from person to person.

  • What does aging imply for human biology?

    Aging implies a combination of genetic, cellular, and environmental changes that lead to a decline in biological functions.

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  • 00:00:06
    In 1997, a French woman named Jeanne Calment
  • 00:00:10
    passed away after 122 years and 164 days on this Earth,
  • 00:00:16
    making her the oldest known person in history.
  • 00:00:20
    Her age was so astounding
  • 00:00:22
    that a millionaire pledged $1 million to anyone who could break her record.
  • 00:00:26
    But in reality, living to this age or beyond
  • 00:00:30
    is a feat that very few, maybe even no humans,
  • 00:00:34
    are likely to accomplish.
  • 00:00:36
    Human bodies just aren't built for extreme aging.
  • 00:00:39
    Our capacity is set at about 90 years.
  • 00:00:42
    But what does aging really mean
  • 00:00:46
    and how does it counteract the body's efforts to stay alive?
  • 00:00:50
    We know intuitively what it means to age.
  • 00:00:53
    For some, it means growing up,
  • 00:00:55
    while for others, it's growing old.
  • 00:00:58
    Yet finding a strict scientific definition of aging is a challenge.
  • 00:01:04
    What we can say is that aging occurs when intrinsic processes
  • 00:01:08
    and interactions with the environment, like sunlight,
  • 00:01:11
    and toxins in the air, water, and our diets,
  • 00:01:15
    cause changes in the structure
  • 00:01:17
    and function of the body's molecules and cells.
  • 00:01:20
    Those changes in turn drive their decline,
  • 00:01:23
    and subsequently, the failure of the whole organism.
  • 00:01:27
    The exact mechanisms of aging are poorly understood.
  • 00:01:31
    But recently, scientists have identified nine physiological traits,
  • 00:01:35
    ranging from genetic changes
  • 00:01:38
    to alterations in a cell's regenerative ability
  • 00:01:41
    that play a central role.
  • 00:01:44
    Firstly, as the years pass, our bodies accumulate genetic damage
  • 00:01:48
    in the form of DNA lesions.
  • 00:01:51
    These occur naturally when the body's DNA replicates,
  • 00:01:54
    but also in non-dividing cells.
  • 00:01:57
    Organelles called mitochondria are especially prone to this damage.
  • 00:02:02
    Mitochondria produce adenosine triphosphate,
  • 00:02:06
    or ATP,
  • 00:02:07
    the main energy source for all cellular processes,
  • 00:02:11
    plus mitochondria regulate many different cell activities
  • 00:02:14
    and play an important role in programmed cell death.
  • 00:02:18
    If mitochondrial function declines,
  • 00:02:21
    then cells and, later on, whole organs, deteriorate, too.
  • 00:02:25
    Other changes are known to occur in the expression patterns of genes,
  • 00:02:29
    also known as epigenetic alterations,
  • 00:02:32
    that affect the body's tissues and cells.
  • 00:02:35
    Genes silenced or expressed only at low levels in newborns
  • 00:02:38
    become prominent in older people,
  • 00:02:41
    leading to the development of degenerative diseases,
  • 00:02:44
    like Alzheimer's, which accelerate aging.
  • 00:02:48
    Even if we could avoid all these harmful genetic alterations,
  • 00:02:52
    not even our own cells could save us.
  • 00:02:55
    The fact remains that cellular regeneration,
  • 00:02:58
    the very stuff of life,
  • 00:03:00
    declines as we age.
  • 00:03:02
    The DNA in our cells is packaged within chromosomes,
  • 00:03:06
    each of which has two protective regions at the extremities called telomeres.
  • 00:03:11
    Those shorten every time cells replicate.
  • 00:03:14
    When telomeres become too short,
  • 00:03:17
    cells stop replicating and die,
  • 00:03:20
    slowing the body's ability to renew itself.
  • 00:03:23
    With age, cells increasingly grow senescent, too,
  • 00:03:26
    a process that halts the cell cycle in times of risk,
  • 00:03:30
    like when cancer cells are proliferating.
  • 00:03:33
    But the response also kicks in more as we age,
  • 00:03:36
    halting cell growth and cutting short their ability to replicate.
  • 00:03:40
    Aging also involves stem cells that reside in many tissues
  • 00:03:44
    and have the property of dividing without limits to replenish other cells.
  • 00:03:49
    As we get older, stem cells decrease in number
  • 00:03:52
    and tend to lose their regenerative potential,
  • 00:03:55
    affecting tissue renewal and maintenance of our organs original functions.
  • 00:03:59
    Other changes revolve around cells' ability to function properly.
  • 00:04:04
    As they age, they stop being able to do quality control on proteins,
  • 00:04:08
    causing the accumulation of damaged and potentially toxic nutrients,
  • 00:04:12
    leading to excessive metabolic activity that could be fatal for them.
  • 00:04:17
    Intercellular communication also slows,
  • 00:04:20
    ultimately undermining the body's functional ability.
  • 00:04:24
    There's a lot we don't yet understand about aging.
  • 00:04:27
    Ultimately, does longer life as we know it come down to diet,
  • 00:04:32
    exercise,
  • 00:04:33
    medicine,
  • 00:04:34
    or something else?
  • 00:04:35
    Will future technologies, like cell-repairing nanobots,
  • 00:04:39
    or gene therapy,
  • 00:04:40
    artificially extend our years?
  • 00:04:43
    And do we want to live longer than we already do?
  • 00:04:46
    Starting with 122 years as inspiration,
  • 00:04:50
    there's no telling where our curiosity might take us.
标签
  • Aging
  • Jeanne Calment
  • Longevity
  • Mitochondria
  • Telomeres
  • Stem Cells
  • Genetic Damage
  • Epigenetics
  • Cellular Function
  • Health