Bronchial circulation

The bronchial circulation is the part of the circulatory system that supplies nutrients and oxygen to the cells that constitute the lungs, as well as carrying waste products away from them. It is complementary to the pulmonary circulation that brings deoxygenated blood to the lungs and carries oxygenated blood away from them in order to oxygenate the rest of the body.

In the bronchial circulation, blood goes through the following steps:

1. Bronchial arteries that carry oxygenated blood to the lungs
2. Pulmonary capillaries, where there is exchange of water, oxygen, carbon dioxide, and many other nutrients and waste chemical substances between blood and the tissues
3. Veins, where only a minority of the blood goes through bronchial veins, and most of it through pulmonary veins.^[1]

Infarction of the lung due to a pulmonary embolism

Blood reaches from the pulmonary circulation into the lungs for gaseous exchange to oxygenate the rest of the body tissues. But bronchial circulation supplies fully oxygenated arterial blood to the lung tissues themselves. This blood supplies the bronchi and the pleura to meet their nutritional requirements.

Because of the dual blood supply to the lungs from both the bronchial and the pulmonary circulation, this tissue is more resistant to infarction. An occlusion of the bronchial circulation does not cause infarction, but it can still occur in pulmonary embolism when the pulmonary circulation is blocked and the bronchial circulation cannot fully compensate for it.^[2]

References

1. "bronchial circulation (anatomy)". GPnotebook. Retrieved 2015-01-04.
2. Thomas H. McConnell (2007). The Nature of Disease: Pathology for the Health Professions. Lippincott Williams & Wilkins. pp. 81–. ISBN 978-0-7817-5317-3.