Concluding the two-part series on the circulatory and respiratory systems, I discuss the biochemical mechanisms by which red blood cells and hemoglobin molecules deliver oxygen to the tissues and carbon dioxide to the lungs, and the mechanisms which regulate these processes. I then consider the respiratory system, giving an overview of the structure and function of the lungs, the process of breathing, control of breathing, and adaptations to high altitudes. Recommended pre-listening is Episode 122: Respiratory and Circulatory Systems Part 2. If you enjoyed the podcast please consider supporting the show by making a PayPal donation or becoming a Patreon supporter. https://www.patreon.com/jamesfodor https://www.paypal.me/ScienceofEverything