You're fine if you stop breathing, as long as you don't start again.

[jackofallgeeks]

This article is amazing. We all know that you can live for weeks without food, days without water, hours without blood, and minutes without air. It's commonly accepted that if you're without air for five minutes you're dead because the cells of your heart and brain have been damaged.

Apparently, new evidence refutes this. It's not the *lack* of oxygen that kills cells, it's the reintroduction of oxygen. And, get this, it's not even just a dumb chemical reaction -- your body apparently kills the cells intentionally.

Apparently it comes down to the mitocondria (I control your arms!) inside the cells. Mitocondria are fascinating little things that I really want to learn more about. Not only are they responsible for regulating cell metabolism, they're also in charge of (vocab word!) apoptosis, the mechanism by which the body destroys abnormal cells (and thus protect itself from cancer). It appears that the body can't tell the difference between a cancerous cell and one that's being reintroduced to oxygen after being deprived of it, so the kill switch is hit and the cell is destroyed.

(Another interesting fact is that one theory of cellular something-or-other holds that mitocondria -- which contain their own DNA, distinct from that of the cell they inhabit -- are actually stand-alone organisms in their own right. It's a bit odd thinking that processes so basic to our existence as cell metabolism and destruction would be relegated to another organism. Makes me think of jellyfish...)

Comments

[thismortalquill.livejournal.com]

Speaking of mitochondria, did you ever play Parasite Eve? The writers had some fun ideas.

[jackofallgeeks.livejournal.com]

No, but I've kind of wanted to. Every time I think, "I've got that game, I should play it," I remember that no, I don't, I have Persona. But I should play that, too.

[thismortalquill.livejournal.com]

I just recently got my hands on a copy of Persona II and even though I haven't had the time to play it, I'm thrilled.

[thismortalquill.livejournal.com]

Oh yes, and technically speaking, our bodies are only comprised of about 10% human cells. Wipe out the intestinal flora and fauna as well as all the other bacteria etc and we're a mere shadow of our former selves. Who said it was a lonely world?

[jackofallgeeks.livejournal.com]

Yeah... The next time I'm feeling low I'll just remember all my intestinal fauna and I'll feel right as rain again. -snerk-

I'm skeptical when you say "our bodies are only comprised of about 10% human cells." It's possible that the area our bodies occupy are literally swarming with other organisms -- on our skin, in our hair, through our serous fluid -- but that hardly counts as 'our bodies' being 'comprised' of them. It's one thing to say that this or that bacteria lives inside our body; it's another thing to say that same bacteria is so integral to our internal functions that it can rightly be considered a part of us. (Though I will concede that some bacteria, particularly in our digestive tract, arguably DO play such a role.)

[thismortalquill.livejournal.com]

All I will say to that for now is for most of the bacteria that lives in/on us, even if it does not contribute directly to our function, keep harmful bacteria from colonizing us, which would result in our death.

Give me some time to dig up the medical journal information on the bacteria count, and I'll have more to say.

[jackofallgeeks.livejournal.com]

And the ozone layer protects us from solar radiation that would kill us, but I'm fairly certain you wouldn't argue that to be a part of our bodies. I remain unconvinced.

[thismortalquill.livejournal.com]

If the ozone layer was produced by organisms that lived in our bodies, then I just might have a case.

[jackofallgeeks.livejournal.com]

If the criteria for "a part of our bodies" now extends beyond "biologically us" and into things like "creatures which are beneficial to us" and "things which our body (as previously defined) create (which we may find beneficial)", then I have an argument for most trees and my 2006 VW Jetta as being a part of my body. I think you're stretching. My car, tress, the ozone, and intestinal fauna are all good and useful things, but they aren't me.

[thismortalquill.livejournal.com]

So if mitochondria really are organisms outside ourselves (yet contained within ourselves) that are integral to our basic functioning, then what?

I am not a biologist, however...

[jackofallgeeks.livejournal.com]

If they aren't our own cells/organelles/whatever -- and I don't have enough information to say one way or another, and what I quoted is only one of many theories in cell biology -- then they aren't, strictly speaking, a part of our body, at least not any more than intestinal fauna. Nevermind the fact that the human body, as such, might never function without them; that just makes us more like jellyfish* than I would have guessed, as noted above.

*strictly speaking what I refer to are not jellyfish. Jellyfish are single organisms, the way we generally think of organisms. Man-o-war and similar creatures are actually colonies of symbiotic organisms which resemble and function in ways similar to jellyfish. I just don't like using "man-o-war" as a term.