Or search for "Endocrine" or "ProfRoofs" or "John Roufaiel" in the medical category.
You can find this video and other helpful videos/materials on my website: www.profroofs.com
This video introduces the details of external and internal respiration. It was produced in response to a viewer's request who had an upcoming exam. In the near future I hope to add more detail. Please feel free to add suggestions. Thank you.