Khan Academy Static

As humans, we really like breathing oxygen. That's because the cells in our body will die if they don't get the oxygen they need to function. This tutorial describes how gases are exchanged between blood and the atmosphere in our lungs, and how oxygen is then pumped through the body by way of blood and the circulatory system.

9812_The_lungs_and_pulmonary_system.html

9814_Circulatory_system_and_the_heart.html

9813_Red_blood_cells.html

9815_Hemoglobin.html