ANATOMY

Detailed explanation-1: -Normally, each pulmonary vein connects directly with your left atrium. In that case, there are four ostia (openings) in your left atrium, one for each of your pulmonary veins. Oxygen-rich blood travels through these openings and into your left atrium.

Detailed explanation-2: -The pulmonary veins bring oxygen-rich blood to the left atrium. The aorta carries oxygen-rich blood to the body from the left ventricle.

Detailed explanation-3: -The right ventricle pumps the blood to the lungs where it becomes oxygenated. The oxygenated blood is brought back to the heart by the pulmonary veins which enter the left atrium.

Detailed explanation-4: -There are 4 total pulmonary veins-with 2 pulmonary veins coming from each lung, left and right-that empty into the left atrium of the heart. Two pulmonary veins emerge from the hilus of each lung, and each pulmonary vein receives blood from 3-4 bronchial veins apiece before draining into the left atrium.