Bronchial a.

The bronchial arteries supply the lungs with nutrition and oxygenated blood. Although there is much variation, there are usually two bronchial arteries to the left lung and one to the right lung.

The left bronchial arteries (superior & inferior) usually arise directly from the thoracic aorta. The single right bronchial artery usually arises from one of the following:

1) the thoracic aorta at a common trunk with the right 3rd posterior intercostal artery.

2) the superior bronchial artery on the left side.

3) any number of the other right posterior intercostal arteries.

The bronchial arteries supply blood to the bronchi and connective tissue of the lungs. They travel with, and branch with, the bronchi, ending about at the level of the respiratory bronchioles. They anastomose with the branches of the pulmonary arteries, and together they supply the visceral pleura of the lung in the process. Each bronchial artery also has a branch that supplies the esophagus.

Note that much of the blood supplied by the bronchial arteries is returned via the pulmonary veins rather than the bronchial veins.

Both the pulmonary aa. and the bronchial aa. bring blood to the lungs, but there are a few key differences. The pulmonary aa. are rather large vessels that bring deoxygenated blood to the lungs from the right ventricle as part of the pulmonary circulation, whereas the bronchial a. are rather small vessels that bring oxygenated blood to the lungs from the left ventricle as part of the systemic circulation.