Contribution to topography and division of blood vessels within the so-called pulmonary acinus in man.

In 60 left lungs of adult humans topography and division of arterial vessels as well as formation of venous vessels and their orifices within the so-called pulmonary acini were studied. The pulmonary acini were supplied by so-called terminal arteries which accompanied so-called terminal bronchioli. The arteries divided into branches of 1st, 2nd, 3rd, 4th and 5th order forming a network of precapillary arterioles consecutively. Two types of division of the terminal artery were distinguished. Possibility of vascularization of a part of the acinus by small artery arising from other terminal artery or its branches was also observed. Blood from the pulmonary acini was carried by so-called intraacinar venules running in the periphery of alveolar sacs. The venules were formed by union of small venules. The intracinar venules ran to the periphery of the acinus reaching so-called interacinar vein. The latter one collected blood from 8-12 venous tributaries.