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Hello, in this second video about the respiratory system physiology, we are going to study the gas exchange.

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The gas exchange is just a simple problem, and the biological principle which is behind this problem is this, that the nature tends to balance.

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Okay, we can summarize this problem within this sentence. If you have an unbalance, yeah, nature will tend to restart to take back this balance.

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okay we are going to see a very simple example regarding this here for example you can you have

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two forests yeah forest one and forest two and in the first one you have a lot of animals

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of this of this type but in the second part you don't have any animal okay so

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So what is going to happen, as you can imagine, is just the migration of half of these animals to fill the forest too.

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This migration stops when you have an equilibrium, a balance, regarding the animal number in the tube forest.

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This happens in this scale, in an organism scale, but also in a molecular scale.

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In this slide, I present you two boxes, the red one and the purple one.

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The red one is full of just one type of molecule, and in the box two is full of the molecule two.

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Here in the box one, we only have molecule one, and in the box two, only molecule two.

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yeah and it is important to say that these boxes can interchange matter and

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energy what is going to happen if nature tends to balance this okay so part of

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the molecules in the box one will go to the box two and part of the molecules

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from the box 2 will go to the box 1 until both boxes

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present an equilibrium in these molecules. The gas exchange fixes a gas

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imbalance. In the gas exchange you have box 1 the alveoli and box 2 the

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blood vessel that's it in the alveoli as you know when you inhale you are taking

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a oxygen enricher so you are going to have this box the alveoli full of

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oxygen on the other side you have the compartment number two which is the

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blood vessel which that where you have basically carbon dioxide okay remember

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that this carbon dioxide comes from the mitochondria okay what is going to

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happen here just this micro this molecule migration yeah the diffusion

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between the blood vessel to the alveoli and the alveoli to the blood vessel

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By doing this, we will finally have part of the oxygen molecules on the alveoli in the blood and part of the carbon dioxide in the blood back in the alveoli to be released in the exhalation process.

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It is important to note that this blood vessel can interchange gases with this alveoli during this time, during this space, but in a normal condition, the gas chains only meet the first third of this pathway.

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okay so you have these two thirds of the pathway just to be sure that the

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interchange has has been done correctly okay so that is the end of the

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presentation and again if you have any question just write me