human anatomy The human body is the structure of a human being. It is composed of many different types of cells that together create tissues and subsequently organ systems. They ensure homeostasis and the viability of the human body. It comprises a he ...

, the bronchial arteries supply the lungs with nutrition and oxygenated

blood Blood is a body fluid in the circulatory system of humans and other vertebrates that delivers necessary substances such as nutrients and oxygen to the cells, and transports metabolic waste products away from those same cells. Blood in the c ...

. Although there is much variation, there are usually two bronchial

arteries An artery (plural arteries) () is a blood vessel in humans and most animals that takes blood away from the heart to one or more parts of the body (tissues, lungs, brain etc.). Most arteries carry oxygenated blood; the two exceptions are the pu ...

that run to the

left lung The lungs are the primary organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the backbone on either side of t ...

, and one to the

right lung The lungs are the primary Organ (anatomy), organs of the respiratory system in humans and most other animals, including some snails and a small number of fish. In mammals and most other vertebrates, two lungs are located near the vertebral co ...

and are a vital part of the respiratory system.

Structure

There are typically two left and one right bronchial arteries. The ''left bronchial arteries'' (superior and inferior) usually arise directly from the

thoracic aorta The descending thoracic aorta is a part of the aorta located in the thorax. It is a continuation of the aortic arch. It is located within the posterior mediastinal cavity, but frequently bulges into the left pleural cavity. The descending thoracic ...

. The single ''right bronchial artery'' usually arises from one of the following: * 1) the

at a common trunk with the right 3rd

posterior intercostal artery The intercostal arteries are a group of arteries that supply the area between the ribs ("costae"), called the intercostal space. The highest intercostal artery (supreme intercostal artery or superior intercostal artery) is an artery in the human ...

* 2) the superior bronchial artery on the left side * 3) any number of the right intercostal arteries mostly the third right posterior.

Function

The bronchial arteries supply blood to the bronchi and connective tissue of the lungs. They travel with and branch with the

bronchi A bronchus is a passage or airway in the lower respiratory tract that conducts air into the lungs. The first or primary bronchi pronounced (BRAN-KAI) to branch from the trachea at the carina are the right main bronchus and the left main bronchus. ...

, ending about at the level of the respiratory

bronchioles The bronchioles or bronchioli (pronounced ''bron-kee-oh-lee'') are the smaller branches of the bronchial airways in the lower respiratory tract. They include the terminal bronchioles, and finally the respiratory bronchioles that mark the start o ...

. They

anastomose An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal ...

with the branches of the

pulmonary arteries A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and ...

, and together, they supply the visceral

pleura The pulmonary pleurae (''sing.'' pleura) are the two opposing layers of serous membrane overlying the lungs and the inside of the surrounding chest walls. The inner pleura, called the visceral pleura, covers the surface of each lung and dips b ...

of the lung in the process. Note that much of the oxygenated blood supplied by the bronchial arteries is returned via the

pulmonary veins The pulmonary veins are the veins that transfer oxygenated blood from the lungs to the heart. The largest pulmonary veins are the four ''main pulmonary veins'', two from each lung that drain into the left atrium of the heart. The pulmonary vei ...

rather than the

bronchial veins The bronchial veins are small vessels that return blood from the larger bronchi and structures at the roots of the lungs. The right side drains into the azygos vein, while the left side drains into the left superior intercostal vein or the accesso ...

. As a consequence, blood returning to the left heart is slightly less oxygenated than blood found at the level of the pulmonary capillary beds. Each bronchial artery also has a branch that supplies the esophagus.

Comparison with pulmonary arteries

It is easy to confuse the bronchial arteries with the pulmonary arteries, because they both supply the lungs with blood, but there are important differences:

Clinical significance

Bronchial artery is considered dilated when its diameter is more than 2 mm. Several causes of bronchial artery dilatations are: congenital heart or lung diseases, obstructions of

pulmonary artery A pulmonary artery is an artery in the pulmonary circulation that carries deoxygenated blood from the right side of the heart to the lungs. The largest pulmonary artery is the ''main pulmonary artery'' or ''pulmonary trunk'' from the heart, and t ...

, and lung inflammation. The bronchial arteries are typically enlarged and in chronic pulmonary thromboembolic hypertension. With modern surgical techniques, bronchial

anastomoses An anastomosis (, plural anastomoses) is a connection or opening between two things (especially cavities or passages) that are normally diverging or branching, such as between blood vessels, leaf veins, or streams. Such a connection may be normal ...

heal well without bronchial artery reconnection. Largely for this reason, bronchial artery circulation is usually sacrificed during lung transplants, instead relying on the persistence of a microcirculation (presumably arising from the deoxygenated pulmonary circulation) to provide perfusion to the airways.

Aneurysm An aneurysm is an outward bulging, likened to a bubble or balloon, caused by a localized, abnormal, weak spot on a blood vessel wall. Aneurysms may be a result of a hereditary condition or an acquired disease. Aneurysms can also be a nidus (s ...

s of the bronchial artery may mimic

aortic aneurysm An aortic aneurysm is an enlargement (dilatation) of the aorta to greater than 1.5 times normal size. They usually cause no symptoms except when ruptured. Occasionally, there may be abdominal, back, or leg pain. The prevalence of abdominal aortic ...

s. Bronchial artery embolisation (BAE) is catheter insertion into a bronchial artery to treat hemopytsis (coughing blood).. Most lung tumors are supplied by the bronchial artery, and they can be treated by chemoembolization (injecting chemotherapy and particles directly into the tumor-feeding artery). The bronchial arteries and their supply of nutrients to the lungs are also attributed to the observation that an occluded (either ligated or by an embolus) pulmonal artery very rarely results in lung infarction. The bronchial arteries can maintain a supply of oxygenated blood to lung tissue.

References

External links

* - "Branches of the ascending aorta, arch of the aorta, and the

descending aorta In human anatomy, the descending aorta is part of the aorta, the largest artery in the body. The descending aorta begins at the aortic arch and runs down through the chest and abdomen. The descending aorta anatomically consists of two portions o ...