Osmosis; mini-lecture, video on Mon., 2.9.15; help understanding gas exchange in the lungs

Today, we discussed osmosis and diffusion.  Osmosis is the diffusion of water.  Diffusion is the movement of particles from where there are many to where there are not as many.

This discussion was to help students better understand how oxygen and carbon dioxide are exchanged between alveoli and capillaries in the lungs. Students learned that the semi-permeable membranes of the alveoli and the capillaries allow oxygen and carbon dioxide to pass between the two structures.  

That way, the capillaries can be rid of the waste carbon dioxide that is carried from each cell.  This carbon dioxide goes from the capillaries into the alveoli and then from the lungs up and out of our mouths when we exhale.

In the opposite situation, we inhale, taking in oxygen.  The oxygen travels to the alveoli, where it goes through the semi-permeable membrane there.  Then it crosses the semi-permeable membrane of the capillaries and is carried through the blood vessels to cells.  There it is combined with glucose (the form of nutrients used by your cells).  The glucose and oxygen are turned into energy by the mitochondria.  This also makes waste carbon dioxide.  

Here is a link to the video we watched.  This video explains osmosis:
https://www.youtube.com/watch?v=IaZ8MtF3C6M