The cell death

Discussion in 'Biology & Genetics' started by Asexperia, Mar 13, 2021.

  1. Asexperia Valued Senior Member

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    In Alzheimer the brain cells die and don't regenerate.
    Does something similar happen in other organs of the body?
     
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  3. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    Many, but not all, tissues and organs of the body can continue to regenerate by virtue of stem cells, immortal cells that remain undifferentiated and proliferative. Stem cells (in muscle, skin, GI tract, bone marrow, liver and more) divide to create new cells – new for old replacement. The activity of stem cells gradually slows as we age through accumulation of mutations. Unfortunately, neural stem cells are active only during embryonic nervous system development and early childhood. Once you reach late teens, your capacity to replace damaged/dead brain cells has ceased. (This isn’t strictly true. There are some neural stem cells that remain active in areas associated with memory and olfaction, but not outside of these limited areas.)

    https://stemcells.nih.gov/info/2001report/chapter4.htm
     
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  5. Asexperia Valued Senior Member

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    There are people who are 80 or 90 years old and still retain their mental faculties.
     
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  7. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    Indeed. In fact, you could raise that to 100-110 yo. Nothing I said precludes that.

    Every human is a mixture of nature and nurture, genetics and environment. Depending on your genes (out of your control) and your lifestyle choices (in your control), you might still be fully cognisant at 100yo, or fully dependent by 50yo.

    We didn’t evolve to be 80+ yo; perhaps that’s one of the reasons behind the lack of neural stem cell activity into adulthood. Our longevity is the product of a wide range of modern technologies. I think it’s a testament to the resilience of human biology that most people do remain relatively cognisant until old age.
     
  8. Write4U Valued Senior Member

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    Yep, the human body has several trillions of cells each undergoing mitosis (cell division), except for certain brain cells, which are used for memory storage.
    https://www.livescience.com/33179-does-human-body-replace-cells-seven-years.html#
    https://www.nature.com/scitable/topicpage/mitosis-and-cell-division-205/#
     
    Last edited: Apr 5, 2021
  9. Write4U Valued Senior Member

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    This maybe of interest.

    Adult Brain Cells Do Keep Growing

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    An illustration of a synapse, which won first prize in the illustration category in the 2005 Science Magazine and NSF Science and Engineering Visualization Challenge.(Image credit: Graham Johnson/NSF)
    https://www.livescience.com/505-adult-brain-cells-growing.html#
     
  10. Hercules Rockefeller Beatings will continue until morale improves. Moderator

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    Yes, adult neurons retain the ability to produce new dendrites and axons. This has been known for quite a while. This is why a brain, in some instances, can ‘re-wire’ itself after brain injury and regain lost functionality. But this is not the same thing as replacement of brain cells through stem cell division. A neuron may be able to send out new dendrites if the old dendrites are degraded, but if the neuron itself dies it is not replaced (with the exception of those areas of the brain I mentioned above).
     
  11. Write4U Valued Senior Member

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    I agree, when a neuron dies it is called "microtubule catastrophe" which stops mitosis.

    Occasionally this is desirable as in the case of stopping cancerous cells from duplicating.
    I am prohibited from quoting pertinent information.

    So just check out this link : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4563776/
     
  12. Write4U Valued Senior Member

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    An ocean dweller organism.
     

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