BRONCHIAL ARTERIES
BRONCHIAL ARTERIES
The
lungs receive blood from two sets of arteries. The pulmonary arteries follow
the bronchi and ramify into capillary networks that surround the alveoli,
allowing exchange of oxygen and carbon dioxide. The bronchial arteries derive
from the aorta. They supply oxygenated blood to the tissues of the lung that
are not in close proximity to inspired air, such as the muscular walls of the
larger pulmonary vessels and airways (to the level of the respiratory
bronchioles) and the visceral pleurae. The origin of the right bronchial artery
is quite variable. It arises frequently from the third right posterior
intercostal artery (the first right aortic intercostal artery) and descends to
reach the posterior aspects of the right main bronchus. It may arise from a
common stem with the left inferior bronchial artery, which origi- nates from
the descending aorta slightly inferior to the point where the left main
bronchus crosses it. Or it may arise from the inferior aspect of the arch of
the aorta and course behind the trachea to reach the posterior wall of the
right main bronchus.