This is great! In other videos, there is no mention of tubes being closed and no mention of expansion and compression of air sacs are happening simultaneously. That in turn gives me a weird picture of what is really going on. This clearly shows everything.
Me too....all the other videos didn't explain that the anterior sack closed the way air can exit from it...which is a pretty big detail in terms of understanding how it works
THANK you for explaining this in a clear way. No other RU-vid video until this cleanly, they all dont mention the closure mechanics of exhalation and inhalation. Neglecting to mention that totally defeats the purpose of understanding; that tripped me up so much and made it so difficult for me to understand. I can't believe this is the only video that understands this
Bird lungs are so freaking cool! This is the first explaination I’ve seen that goes through whats going on in both sets of air sacs during inhales/exhales (instead of following a single breath), and its also the first time I’ve seen countercurrent exchange explained. Freaking fascinating and you make it so clear to understand too!
The valves are so called aerodynamical ones. They are obtained by connecting the pipes to the main tube at right angles. For example during inhalation air goes straight to the posterior sacs situated at the end of the main tube. Anterior sacks are not so efficient in taking the air, as it passes quickly and does not intend to turn at the right angle into the opening leading to the anterior sacks. It means that between two ends of the lungs a differnce of pressure is created. In my opinion muscular valves would be better, yet the aerodynamical ones probably proved to be sufficient enough.
Wait, so are you saying that there is no actual closure of the air pathways, and ONLY a differential in the efficiency of the flow paths for different directions? O are you saying that both apply?
I saw somewhere that countercurrent exchange of gasses from blood in animals was compared with the same principal in heat exchangers working best in a similar counter current manner, so that makes total sense that it would be reminiscent of thermodynamics.
Very nice, best explanation i could find. Now my question, what happens if birds hold their breath? (eg penguins) do they move the air back and forth, or only blow up posterior and slowly fill up anterior while still getting the oxigen?
Very good presentation. Describing inhalation in a single picture rather than the typical cycle 1/cycle 2 pictures is much more straightforward and understandable. In two places the narration is wrong, with speako's of anterior for posterior and air for blood.
Fully agree. In other presentions, I wondered why it was more efficient if the bird had to inhale and exhale twice to process one breathful of air. But if I am understanding this video correctly, it is because, as you said, the inhale parts of both cycles and the exhale parts of both cycles are happenning simultaneously, resulting in it taking two inhale/exhale cycles, but processing two breathfuls of air as it does that. Thanks to the video creator.
Thank you so much for the details of the closed tubes. Now it makes sense. Is there any evidence for this issue, books or studies, or is it just your personal logical conclusion?
in the class and in the book there isn't a mention of anything closing... I'll review again... In the class the instructor thought the air went through the "lungs" both going in and going out.. I don't know
Thanks for video it was very helpful. There’s one thing I’m unsure on though. As far as I’m aware the gas exchange takes place between the air capillaries and the blood capillaries. I’m looking at websites and diagrams that have given me the impression that the capillaries are at right angles to the main parabronchi tubes and parallel to the air capillary projections. This would mean that air is travelling through the main parabronchi tubes at right angles to the blood capillaries and so isn’t a counter current. Is there something I’m missing? I think the pulmonary veins and arteries still travel parallel to the main parabronchi tube but not the blood capillaries where as I got the opposite impression from the video.
The last time I checked on this point, the answer wasn't actually known. The circulation and path of both air capillaries and blood capillaries is complex, and it hasn't been easy for researchers to model and understand. Researchers sometimes refer to it as modified counter-current exchange system. It seems clear that bird lungs must have at least some features of counter-current exchange, as it seems that counter-current exchange is the only way to account for the high amount of oxygen they are able to extract from air.
There is always one, and no, it most certainly does NOT "have to" be designed by a creator. Compared to the brain or the eye, just to name two, this system is a "no brainer", so to speak. Go learn about evolution WITHOUT spooky nonsensical, completely unsupportable (go ahead, try, you will fail, as it ALL comes back to faith, as all religions REQUIRE, not data, not experience, just believe it, because some book says to) religious pre-bias and you will find out. Many evolutionary "selections" start out functioning as something else, feathers for heat retention as an example. If a "creator" exists, why would features have to progress through the obvious phases they do, given both the fossil and genetic records? And why would the "creations" have both organs that are "phasing in" and "phasing out" of existence through time. Did the creator initially screw up his creations, and he later had to fix them, throughout the entirety of time? None of that makes one lick of sense. A creator may or may not exist, who knows, no data, but a creator that "meddles" in our affairs (plagues, hurricanes, floods, turning people to salt (utterly ridiculous), comets, eclipses, ad infinitum, and "smotes" people for their "actions" we now know is neither required or exists. God is humanities "fill in the blank" for things unknown or the inexplainable. Nothing EVER has to "be designed by creator" unless we are just totally lazy and uninterested in finding out how REALITY really works. You will read this, and dismiss ALL of it, I am fairly sure, because you have been literally brainwashed to do that, usually from a very young age (before you CAN know better, THAT is by DESIGN, I wanna tell ya). If you want to continue through life with the crutch of religion, that is fine, but please stop with the completely inane "must be a creator" nonsense. No, it doesn't "must", not even the teeniest tiniest bit, unless you just negate ALL critical reasonable thought, as religion REQUIRES you to.