Want to learn more about the circulation of blood through the heart and the rest of our body. Watch this video. Initially, this video explains about hemoglobin and why it resides in the red blood cells in the blood. Next, it explains the flow of blood through the body, focusing on deoxygenated and oxygenated blood and how they flow through the heart. This section of the video also explains the role of the lungs in the circulatory system. Finally, the flow of blood through the heart is explained in even more detail. Here, the various relevant sections of the heart, their functions and their role in the circulatory system is explained.