Blood Supply to the Lungs 

The Common Vein Copyright 2007

In this section we discuss the blood supply to the lungs.  There are two sets of arteries.  The transport system needs a relatively small amount of oxygenated blood and the bronchial system is supplied by the bronchial arteries, while the exchange system has needs to supply a  tennis court sized surface are and is supplied by the larger pulmonary arterial system.

Blood Supply to the Airways – The bronchial arteries 

There are usually two bronchial arteries. The left artery arises from the aorta, and the right arises either from the 3rd intercostal artery (30%), with the 3rd intercostal as a common origin (intercostobronchial artery), from the thoracic aorta, or from one of the other proximal intercostal arteries. It is not uncommon to have 3 or 4 intercostal arteries.
The bronchial arteries supply the bronchi and the tissue of the lungs with oxygenated blood. As systemic vessels their pressure is at systemic levels, with a mean pressure that is 5-6 times higher than the mean pulmonary pressure (15mmHg.).

The bronchial venous system drains into the right atrium and the azygous system.