It would have been good to have an animation showing all parts of the respiration system working simultaneously instead of just following the movement of air from one "gasp" of air.
Uni-directional flow in the lung makes no sense, if it takes two respiratory cycles to aerate the lungs once. When all the air-sacs inflate, air flows from the bronchus through the lung and into all the air-sacs. When the air-sacs deflate, the air flows through the lungs a second time and out via the bronchus. Thus, the lungs are aerated twice during each respiratory cycle as a bi-directional system.
It is confusing, there are better animations on the process but from what i understand technically the airflow through the lungs is not unidirectional, as air has to pass through the lungs to reach either set of air sacs, but the air movement in the actual gas exchange part of the lung is happening unidirectionally. Gas exchange happens in the parabronchi section of bird lungs, which only takes in air from the posterior air sacs. and then empties into anterior sacs. I don't believe there is any air intake into the parabronchi from the anterior during the inhale, as the parabronchi is then simultaneously emptying into the anterior sacs.
It is unidirectional because the lungs always have oxygen rich air flow over them regardless of inhale or exhale. Follow one "breath" and you will see that it follows one long direction, instead of back where it came from like it bidirectional breathing (us). One breath goes down to the posterior air sacs, then to the lungs, then to the anterior, then out again. All the while, another new breath is following behind so the lungs always have oxygen. In ours there is no lagging breath, it is just in and out.
The animation clearly shows the posterior air-sacs and the anterior air-sacs inflating at the same time and deflating at the same time. Therefore the air must flow from the trachea/bronchus, through the lungs, to and from all air-sacs at the same time. Thus a two-way flow. @@ChandlerCarr-wg9bi
The animation correctly shows all of the air-sacs acting simultaneously, which means that air does NOT move through the lungs from one air-sac to another. The air-sacs, collectively, can only draw air from the lungs, replaced by air from the bronchus. The air-sacs, collectively, discharge through the lungs and out of the bronchus.@@ChandlerCarr-wg9bi
@@ChandlerCarr-wg9bi Uni means 'one' or 'single.' the airflow moves in TWO directions (i.e. front to back, and back to front), making it technically bi-directional.
But there still have dead air in the trachea, especially those bird with long neck. It's like a diver breath in and out underwater through a single hose, there always have mixed air trapped in the hose unless implied two hoses for in and out airways.
@JonBrase i made an assumption of one hose diving to explain the dead air trapped in bird's neck. Of course, you're right about the real diving. The regular is doing the same way as fish breathing, which is the most efficient breathing system. Fish breathe in and out in two different ways like jet engines.
Linking this an evolutionary history from dinosaurs is pure folly; if birds evolved over time from reptiles, then that would mean this complex system was advantageous before it was complete. No such thing has been proven; the irreducible complexity of this system demonstrates that random sequential mutations over a long period of time could not have taken place, because the pre-bird animal wouldn't survive before it could fly. I really appreciated watching this, but i think your conclusion of origins at the end was a mistake.
Evolution doesn't necessarily have to be sequential, or at least not the way you are thinking it. Large steps can be taken due to quick mutations. Regardless, even less formed air sacs are beneficial, such as in crocodiles. We know that dinos like the therapods and sauropods had air sacs. And their air sacs were not "less formed" or "less functional", they were vital for metabolic rate. Birds are dinosaurs, this is know. And birds gained this air sacs respiratory system from the ancestors of not just dinosaurs but also crocodiles.
i have always been confused about how it works, because i cant make sense of the charts and text descriptions, but this cleared everything up :)
In middle school I had heard of this and that it was amazing. Though more efficient, this takes WAY more space & is more complicated!
Very interesting. Thank you. I'm reading a book by Ben Garrod and couldn't quite picture how Avian respiration worked. This video was helpful.
It would have been good to have an animation showing all parts of the respiration system working simultaneously instead of just following the movement of air from one "gasp" of air.
Uni-directional flow in the lung makes no sense, if it takes two respiratory cycles to aerate the lungs once. When all the air-sacs inflate, air flows from the bronchus through the lung and into all the air-sacs. When the air-sacs deflate, the air flows through the lungs a second time and out via the bronchus. Thus, the lungs are aerated twice during each respiratory cycle as a bi-directional system.
It is confusing, there are better animations on the process but from what i understand technically the airflow through the lungs is not unidirectional, as air has to pass through the lungs to reach either set of air sacs, but the air movement in the actual gas exchange part of the lung is happening unidirectionally.
Gas exchange happens in the parabronchi section of bird lungs, which only takes in air from the posterior air sacs. and then empties into anterior sacs. I don't believe there is any air intake into the parabronchi from the anterior during the inhale, as the parabronchi is then simultaneously emptying into the anterior sacs.
It is unidirectional because the lungs always have oxygen rich air flow over them regardless of inhale or exhale. Follow one "breath" and you will see that it follows one long direction, instead of back where it came from like it bidirectional breathing (us). One breath goes down to the posterior air sacs, then to the lungs, then to the anterior, then out again. All the while, another new breath is following behind so the lungs always have oxygen. In ours there is no lagging breath, it is just in and out.
The animation clearly shows the posterior air-sacs and the anterior air-sacs inflating at the same time and deflating at the same time. Therefore the air must flow from the trachea/bronchus, through the lungs, to and from all air-sacs at the same time. Thus a two-way flow. @@ChandlerCarr-wg9bi
The animation correctly shows all of the air-sacs acting simultaneously, which means that air does NOT move through the lungs from one air-sac to another. The air-sacs, collectively, can only draw air from the lungs, replaced by air from the bronchus. The air-sacs, collectively, discharge through the lungs and out of the bronchus.@@ChandlerCarr-wg9bi
@@ChandlerCarr-wg9bi Uni means 'one' or 'single.' the airflow moves in TWO directions (i.e. front to back, and back to front), making it technically bi-directional.
Tnx, you make it a lot easier to understand.
This makes me wonder who boreal birds prevent heat loss during breathing, when so much of their body is full of air.
So they never get fresh cold air into their lungs? They can only feel the crisp coolness of a winter day in their in-sacs?
I learned about this while reading about some leaked alien anatomy study 😂
Dude I know this was posted a month ago but how the hell did we both end up here from that leaked study 😂
haha, that's amazing 😂
we just were curious how the most efficient respiratory system on earth worked 🤓
@Birnasuc birds not the most efficient breathers on earth, fish are
@@johncitizen5130of air????
@@edgaral of oxygen
It's great
Now I can get full marks in exam, thanks🙂
Hffff finalllyyyyy..thanks to you that was't that difficult to understand
But there still have dead air in the trachea, especially those bird with long neck.
It's like a diver breath in and out underwater through a single hose, there always have mixed air trapped in the hose unless implied two hoses for in and out airways.
For divers, exhaled air is generally vented directly from the regulator, so it doesn't end up in the air supply hose.
@JonBrase i made an assumption of one hose diving to explain the dead air trapped in bird's neck. Of course, you're right about the real diving. The regular is doing the same way as fish breathing, which is the most efficient breathing system. Fish breathe in and out in two different ways like jet engines.
Nice
Thank you. This is very helpful
0:49
Comforting to know how birds breath with the forest fires we have.
Nice vid mr. jahn
Wakter walter*
Huh.
Linking this an evolutionary history from dinosaurs is pure folly; if birds evolved over time from reptiles, then that would mean this complex system was advantageous before it was complete. No such thing has been proven; the irreducible complexity of this system demonstrates that random sequential mutations over a long period of time could not have taken place, because the pre-bird animal wouldn't survive before it could fly. I really appreciated watching this, but i think your conclusion of origins at the end was a mistake.
Evolution doesn't necessarily have to be sequential, or at least not the way you are thinking it. Large steps can be taken due to quick mutations. Regardless, even less formed air sacs are beneficial, such as in crocodiles. We know that dinos like the therapods and sauropods had air sacs. And their air sacs were not "less formed" or "less functional", they were vital for metabolic rate.
Birds are dinosaurs, this is know. And birds gained this air sacs respiratory system from the ancestors of not just dinosaurs but also crocodiles.
Birds are descendants of reptiles and are technically still apart of the clade Reptilia.. So they are technically "glorified reptiles".