[The smooth muscle tissue of the bronchi (histogenetic characteristics)]

Formation of bronchial smooth muscular tissue was studied in embryos, newborns and mature rats using electron microscopy, cellular dissociation, morphometry and cytophotometry. Ultrastructural and morphometrical characteristics was given for developing and mature smooth myocytes. Growth of heteromorphy was demonstrated in bronchial wall smooth myocytes in postnatal histogenesis. This allowed to distinguish subpopulations of small, medium and large cells that vary in linear parameters, nuclear-cytoplasmic ratio, nuclear ploidy and amount of summary proteins. These data allow to discuss definitive smooth muscular tissue of bronchi as an integrative differon.