The pulmonary arteries are blood vessels that carry deoxygenated blood from the heart to the lungs. Specifically, they transport blood from the right ventricle of the heart to the lungs for oxygenation. This process is essential for removing carbon dioxide and replenishing oxygen in the blood. Once in the lungs, the blood passes through tiny capillaries surrounding the alveoli, where gas exchange occurs. After this exchange, the now oxygen-rich blood returns to the heart through the pulmonary veins, ready to be distributed to the rest of the body.