Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Life and death (merged)

  1. Jul 20, 2006 #1
    Hi, I was wondering that what causes a man to die, naturally. If he is constantly being damaged then how do young kids get better day by day rather than getting more sick. If it is b/c after a certain age, our cells stop growing(not reproducing), then why is that? What causes it to?
     
  2. jcsd
  3. Jul 20, 2006 #2
    Well, cells never stop re-produce, even after death. Nails and hair grow after a human has died, if so for a minute.

    When a cell is dividing it sometimes mutates. The figure is 1 mutation / 10.000 cell divisions. Some of this mutations can be taken care of, but others cannot. As the cell division moves forward, more and more mutations and damages (from the oxygen we breath among others) builds up (look at the skin of elderly for example) and in the end, it cease to function and you die.

    That was a short explanation as a general overview.
     
  4. Jul 20, 2006 #3

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    I do think that this is an old wives tale.
    As I understand it the skin dessicates and shrinks
    giving the apperance of some growth occurring.
    All the cells will be dead by the time the body hits room temperature.

    I think what Mattara is talking about here is called the Hayflick limit. If everything else worked perfectly then, as I understand it, you might live to be about 130yrs based on this.

    However, cells have DNA locking/unlocking mechanisms (methialation sp? but there is more than one). These determine if a cell is a heart cell or a liver cell for example. Over time these locks/unlocks get inappropriately applied. Perhaps, the responsible molecules leak from cell to cell, but as I understand it nobody quite knows why. After a while a heart cell isn't quite a heart cell and a liver cell isn't quite a liver cell.
    When enough of this kind of damage accumulates systems fail and you die.

    Its been a while since I looked at this stuff so this may not be 100% correct or its out of date.
     
  5. Jul 20, 2006 #4
    What about the myth that poeple used to live for about 500 years? What about the other myth about the scientists that claim that they can keep a human alive for a 1000 year if they can keep him locked in a room.(perfect condition, no scratches, wounds, perfect circulation, etc.) Are they just myth?
    Btw, is it possible in some age for scientist to fix or stop mutation?
     
  6. Jul 20, 2006 #5
    Life

    What is the diff. b/w alive and dead. If you put all the organs together, life doesn't start. What causes life?
     
  7. Jul 21, 2006 #6
    That is highly unlikely as there are many different types of mutations resulting from radiation, chemicals or spontaneous.
     
  8. Jul 21, 2006 #7

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    how do you know that?
    Just because you haven't found a clever way to do so, it doesn't follow that others won't ever be able to do just that.
     
  9. Jul 21, 2006 #8

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    A dead organ is a dead organ.
    It might look much the same but all the working bits have been destroyed.

    I might point out that there are transplants. Much like what you are talking about but on a smaller scale.
     
  10. Jul 21, 2006 #9

    Another God

    User Avatar
    Staff Emeritus
    Gold Member

    Because life is cellular. Cells are molecular. If you pull the organs apart, the lung organ cant provide oxygen to the blood cells which then cant provide oxygen to the brain cells, the brain cells stop respiring and hence stop producing energy which allows them to continue replicating RNA/DNA and producing proteins. Without their DNA, RNA and proteins they cant maintain their cellular machinery and waste will acumulate, errors will accumulate and they will die (Necrosis). This will eventually result in waste and crud spilling out of them harming the other cells around them which are also suffering a similar fate.

    This will happen all throughout the body. No cellular function = No life no matter how well you stick the dead celled organs together.

    In other words, Missing organ(s) => Insufficient nutrients/oxygen/other to the cell => Problems with cellular machinery => cell dies => organ cant work without working cells => body cant work without organs => Death

    Shane
     
    Last edited: Jul 21, 2006
  11. Jul 21, 2006 #10

    Another God

    User Avatar
    Staff Emeritus
    Gold Member

    Complete Myth. Being alive is deadly. Trying to extend lifespan is actively pursued these days more than ever. if you are interested in the quest for eternal youth, then www.imminst.com is the focal website for that.

    The Hayflick limit is a consideration, but that really isn't the cause of our lifespan limitation or even our aging. Cell replication limits are actually a protective adaptation (most likely against cancer). The cells can easily overcome the cellular division limit (..for instance..cancer cells). The reason we age is more commonly attributed to oxygen radical damage linked with (causing as well) mutations of the DNA, mutations of proteins causing accumulation of waste products in each cell and slowly building chain reaction coming from these problems. But the fact is that we still dont know exactly why we age (thats my objective.. to figure that out).

    Can we stop mutations? No way. Can we repair them? Well the body certainly does all the time, but mistakes will be made, and wastes willa ccumulate and you can't do everything perfectly ever. The best chance we have is finding some way to 'purge' the system on a regular basis, or something like that. See, life does this by creating generations. Every new baby comes from one clean cell. The cell has been created from two cells of unique DNA combination which is generally "Clean" of all waste products and harmfull components. You can't say it has no mutations, because it IS the prototype. So it sets the basis. If its DNA doesn't manufacture a working organism, then it will die and life wil have to try again.. If it does produce a functional organism though, you have just got another lifespan of time from this species.

    If we could someway replicate this purging process in our own bodies without giving up our conscious continuity...then we could be eternally young.

    Shane
     
  12. Jul 22, 2006 #11
    Is there a way though to put together organs and make a living being?(theoretically)
     
  13. Jul 22, 2006 #12

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Since dead organs have undergone apotheosis on a cellular level, and bacteria have nibbled on it, and shat in it (called "rotting"), these processes would have to be reversed before the organs are potentially functional.
     
  14. Jul 22, 2006 #13
    If thats the fact then why is mutation so predictable? How come everyone starts aging almost the same age?
     
  15. Jul 22, 2006 #14
    no no no, implying that they have been frozen. Oh forget about it, assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why???
     
  16. Jul 22, 2006 #15

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    Water, when frozen at a normal rate CRYSTALLIZES.
    What do you think happens to the membranes&interior machinery of the cell when thousands of sharp spikes suddenly pierces into them?
     
    Last edited: Jul 22, 2006
  17. Jul 22, 2006 #16
    I told you, forget about freezing, concentrate on my suppose thing, that really nails my point down.

    assume this situation, somebody has just passed away b/c of heart attack, now if you replace his heart, and may be brain coz it was damaged, would he be able to come back even though his organs right now are just fine. No, why???
     
  18. Jul 22, 2006 #17

    NoTime

    User Avatar
    Science Advisor
    Homework Helper

    If anybodys coming back, it would be the person whos brain it is.
     
  19. Jul 22, 2006 #18
    So you are saying you can back bring dead back to life, I am sorry but besides the zombie phenomenon, this is the first. YOu should really try it, it will make a millionare. Get real man. YOu can't do that, once a person is dead, he stays dead. The only case I have heard of a person coming back from dead is when died by freezing and then brought back to life 4 days after that. But that is a popular phenomenon, has happened couple of times. But what you are saying, replacing braines, do you know how revolutionary that can be. All I am saying is that it can't be done coz if it could have been, all those funds havn't had gone to a waste. All I want is the reason of why it can't be done.
     
  20. Jul 22, 2006 #19

    Moonbear

    User Avatar
    Staff Emeritus
    Science Advisor
    Gold Member

    Arildno and Another God have supplied this answer already. Energy is required to maintain the biochemical reactions that support cellular and organ functions. When that energy supply is stopped, cells begin to undergo different biochemical reactions, and deteriorate. Once the damage is done, it's not reversible. The heart and brain are usually focused upon when determining that death has occurred, because the failure of those organs rapidly results in failure of all the other organ systems. Otherwise, a single organ failure can be survived through transplants, as long as it can be replaced before other effects have built up to damage more organs, such as building up of toxic waste products in the body following liver failure.

    Once a person or other animal has died, decay of the tissues sets in quite rapidly, which is why they can no longer be revived.

    As best I can tell, this is the answer to the question you're asking. If you're instead asking what makes something alive, then I'm afraid we do not have an answer for you. You might find it of interest to discuss under the subject of philosophy, but biology doesn't yet provide that answer.
     
  21. Jul 22, 2006 #20

    arildno

    User Avatar
    Science Advisor
    Homework Helper
    Gold Member
    Dearly Missed

    He evidently believes in the existence of a mysterious spark of life that is somehow independently existing from fully functional, but inert organs.
    (Those CAN be brought into "life" again, as medical transplants show).
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Have something to add?



Similar Discussions: Life and death (merged)
  1. What is Death? (Replies: 7)

  2. What is death? (Replies: 11)

  3. Natural Death (Replies: 4)

  4. Death of an organism. (Replies: 5)

Loading...