Why is the pulmonary circulation called pulmonary?

The small circle is called the pulmonary because it passes through a network of capillaries through the lungs. There is a change in the composition of the blood. The bonds between hemoglobin and carbon monoxide are broken. Hemoglobin, thanks to the iron, creates new bonds with oxygen. This is how the venous blood changes to arterial. The process itself is pretty fast. In total, the blood passes in a small circle in 6 seconds. It takes 21 seconds to bypass the blood around the systemic circulation. In total, the blood makes a little more than two rounds of the body per minute.