The respiratory and circulatory systems work together to bring oxygen to the cells in the body. The circulatory and respiratory systems absorb oxygen from the air and transfer it to all parts of the body while absorbing carbon dioxide from the body and releasing it into the air. When a person inhales, the lungs expand and fill with fresh air. The respiratory system interacts with the circulatory system to transfer oxygen from fresh air to red blood cells in the lung arteries while also releasing carbon dioxide from the blood into the air in the lungs. When a person exhales, this used air leaves the body. The heart pumps the blood with the oxygenated red blood cells from the lungs via the arteries throughout the body where the oxygen is released into the cells and carbon dioxide is absorbed. The heart pumps the used blood back through the veins to the lungs, and the cycle repeats itself. The respiratory system takes oxygen from the air to the lungs, where the oxygen is transferred to the blood. The human respiratory and circulatory systems work together to supply the body with oxygen and get rid of waste carbon dioxide. While the former deals with air and the latter with blood, they work together seamlessly by coordinating the functions of the many parts of each system.
