THE PECULIARITIES OF THE PULMONARY ACINUS STRUCTURE IN THE RESIDENTS OF WESTERN SIBERIA

Pulmonary acinus architectonics and parameters were studied in six men aged 19-27 years that permanently lived in the city of Novosibirsk. The study was conducted on the serial histological sections by using morphometry and volumetric graphic reconstruction of the acini. In a typical acinus, three generations of the respiratory bronchioles, four generations of the alveolar ducts, and one generation of the alveolar sacs (AS) were found. All the intraacinar components branched in the form of dichotomy, most commonly, irregular. It was shown that the acini were regularly asymmetrical, 32% of branches of the alveolar ducts of the second order had no continuation and ended with AS. In the same way, two thirds of the third order alveolar ducts also continued into AS, i. e. about 40% of branches are rudimentary. Intra-acinar path from the first alveoli in the respiratory bronchioles to the terminal alveoli is equal to 7.2±1.0 mm. The peculiar feature of the acinus of the Siberian residents is an increased transitional zone and a distal shift of respiratory zone by one generation of branches in the direction from the conducting airways, which reduces its cooling during breathing cold air in winter.

human pulmonary acinus, acinar microstructures, transitional zone, respiratory zone