The right and left coronary arteries deliver oxygenated blood to the lungs
Oct 12, 2014 The pulmonary trunk is a short and stout (wide) structure that is about 5 cm in length and 3 cm in diameter, which branches into 2 pulmonary arteries; the left and right pulmonary arteries, which act to deliver deoxygenated blood to its respective lung.The right pulmonary artery carries blood to the right lung while the left pulmonary artery carries it to the left lung. The pulmonary arteries are unique in that unlike most arteries which carry oxygenated blood to other parts of the body, the pulmonary arteries carry deoxygenated blood to the lungs. the right and left coronary arteries deliver oxygenated blood to the lungs
The second reason for this tricky route is that the rest of the body wants fully oxygenated red blood cells, not just castoffs from the heart. If the heart replenished its own oxygen supply directly from the river of blood flowing through it, the blood leaving the heart would have less oxygen to deliver to the body.