Human Anatomy (with the Fundamentals of Dynamic and Sports Morphology) - Ivanitsky M. F. 2008

The Doctrine of the Heart and Blood Vessels
Vessels of the Lesser (Pulmonary) Circulation

The Pulmonary Circulation passes through the Lungs, serving to oxygenate the Blood and release carbon dioxide from it into the air filling the alveoli. The pulmonary circulation begins in the right ventricle and ends in the left atrium. It is sequentially formed by the pulmonary trunk, the right and left pulmonary Arteries, their segmental branches and smaller ramifications transitioning into capillary networks surrounding the alveoli, as well as Veins that progressively enlarge along the blood flow to ultimately form four Pulmonary veins. The division of the pulmonary trunk into two pulmonary arteries occurs beneath the aortic arch at the level of the 4th thoracic vertebra. The left pulmonary artery is shorter and thinner than the right one. The left pulmonary veins are also shorter than the right ones, which is due to the left-sided position of The Heart.

In the lungs, there are numerous anastomoses between the VESSELS OF THE systemic (bronchial branches arising from the Thoracic Aorta) and pulmonary (ramifications of the pulmonary artery) circulations. Blood capillaries surround the alveoli in a dense network. At the Base of the alveolus, their diameter is larger (20–40 µm) than on its opposite surface (6–11 µm). The total working surface area of the capillaries reaches 60–90 m2.



Last update: 08/08/2026

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