looking at wikipedia, there is more information:
> Frogs can survive many freeze/thaw events during winter if no more than about 65% of the total body water freezes
Biological Miracle – Wood Frog
81–90 of 145 posts
Re: Biological Miracle – Wood Frog
#82Earlier quoted context omitted.
The frog is not frozen solid.
Interestingly, you can freeze a rat solid in liquid nitrogen--completely solid right through--and then thaw them out in a microwave and they actually survive. Well, many of them survive. For a while. Okay, it's not good for the rats but it's still crazy that it works.
Where can I read more about this? If this was a fact I think people would be way more excited about cryonics. Casually browsing wikipedia suggests that we are not there yet with the ability to thawn large animals or even organs.
Re: Biological Miracle – Wood Frog
#83Earlier quoted context omitted.
my poor knowledge of biology says it's a deeply unsatisfying "heart beats when enough of the body has thawed for it to beat." If the heart depends on the brain at all in frogs.
It doesn't, even in humans. There is an independent circuit of special muscle cells right on it that keeps it beating. So starting and stopping the heart in a controlled manner is pretty interesting, because it has to be well-timed, and there are few obvious and reliable inputs to control it, especially when thawing.
Why doesn't my heart keep beating if my brain dies then? Or would it?
Re: Biological Miracle – Wood Frog
#84Earlier quoted context omitted.
It's a bit of a fantasy that we might find a perfectly well preserved dinosaur in a glacier somewhere.
Not possible - the oldest ice we've found on the planet is much less than 10 million years old. Even if some area remained frozen long enough to contain an intact dinosaur, it would be buried deeply enough and under enough pressure to just be a bit more arctic oil by now.
What about amber? Don't tell me that's a lie too
Re: Biological Miracle – Wood Frog
#85Wood frogs only live 3-5 years, so they probably only go through a max of 5 of these cycles. I wonder how much cellular damage they accumulate during these cycles that they can tolerate due to short lifespans. They also have ~10,000x less neurons than a mammal. Even if you had the biochemistry that was able to do this, how many cycles could a higher life form tolerate this, assuming it would even work? Complex life s…
I don't understand why we're not allowed to regrow limbs. What did that make room for in our DNA?
Re: Biological Miracle – Wood Frog
#86Could such a mechanism be used for interstellar travel ?
No. Article says they have 1000x sugar in their blood. When we get to 10x we tend to die.
Re: Biological Miracle – Wood Frog
#87Earlier quoted context omitted.
Interestingly, you can freeze a rat solid in liquid nitrogen--completely solid right through--and then thaw them out in a microwave and they actually survive. Well, many of them survive. For a while. Okay, it's not good for the rats but it's still crazy that it works.
Where can I read more about this? If this was a fact I think people would be way more excited about cryonics. Casually browsing wikipedia suggests that we are not there yet with the ability to thawn large animals or even organs.
I can't source this because I read it years ago, but I believe that there is some science that says that a major factor (not the only major factor, but a major factor) is body mass and volume. Essentially, the speed at which the core organs go from operating temperature to frozen is crucial, and it's also important for them to be deprived of oxygen when that happens. Humans are just... too big.
Re: Biological Miracle – Wood Frog
#88Earlier quoted context omitted.
If it gets frozen in a heavily contracted form, unthawing it will trigger at least one half-beat: could that be enough to restart it?
Hard to imagine that this is significant, given that the (un)thawing is likely quite slow. Did not think that my early morning would be spend trying to imagine how thawing a frog works. :)
Good point for sure.
Re: Biological Miracle – Wood Frog
#89Earlier quoted context omitted.
It doesn't, even in humans. There is an independent circuit of special muscle cells right on it that keeps it beating. So starting and stopping the heart in a controlled manner is pretty interesting, because it has to be well-timed, and there are few obvious and reliable inputs to control it, especially when thawing.
Why doesn't my heart keep beating if my brain dies then? Or would it?
I understand that it would keep beating until you are provided oxygen. That’s my understanding understanding of brain death at least.
Re: Biological Miracle – Wood Frog
#90> Nobody yet understands what starts the wood frog’s heart after being frozen and inert for the entire northern winter. To me, that's the most fascinating part of the (already quite fascinating) story. Frog is frozen solid, there is no (to our knowledge) heartbeat or brain activity. It thaws and something happens that gets it going again. I have trouble imagining what that mechanism could even look like. Tiny portion…
What puzzles me is... it is not just the heart but the entire circulatory system. Maybe it is that thawing happens in reverse with the extremities, then the rest of the system thawing, with the heart being last. Would be a biological advantage in this case for the heart to be centrally located.
> Maybe it is that thawing happens in reverse with the extremities, then the rest of the system thawing, with the heart being last
FTA: In spring, the wood frog thaws from the inside outward. First the heart starts beating. Then the brain activates. Finally, the legs move.