Final answer:
The pulmonary circulation carries deoxygenated blood from the heart to the lungs for oxygenation and returns oxygenated blood back to the heart.
Step-by-step explanation:
The pulmonary circulation is part of the circulatory system that carries deoxygenated blood from the heart to the lungs for oxygenation and returns oxygenated blood back to the heart. When the right ventricle contracts, it pumps blood into the pulmonary trunk, which divides into the left and right pulmonary arteries that carry the blood to each lung.
Inside the lungs, the pulmonary arteries branch into smaller arteries and arterioles, finally leading to the pulmonary capillaries where gas exchange occurs between the blood and the alveoli. After oxygenation, the blood returns to the heart through the pulmonary veins, specifically the four pulmonary veins, and enters the left atrium.
These arteries transport deoxygenated blood to the lungs for gas exchange. The pulmonary semilunar valve prevents backflow into the right ventricle. Post gas exchange, oxygen-rich blood returns via pulmonary veins to the left atrium, eventually entering the left ventricle through the mitral valve.