If you are interested in looking at a more in depth view of what goes on behind the scenes on a functional level, these are a great resource.
I added his site as a permanent link off of my side-bar under the new link category of Flight EMS.
Thanks again Dr. Welton. My apologies for it taking so long to add it!

Emily, I’m happy to share with everyone, feel free to use if it’s helpful. They are set up primarily for fixed wing but there is some good discussion on flight physiology, gas laws, etc. that may be useful for additional background. I may still have the original MS Word files, if anyone is interested send me a private email.
John
Thanks for the site!, am new to Flight nursing ( about a month) and I am like a sponge trying to learn as much as i can.