Bronchioles and alveoli (Latin)

On the right, a macroscopic view shows the branching of the arbor bronchialis. On the left, the microstructure of bronchioli respiratori, alveoli and associated neurovasculature is shown. Bronchioli arise from the bronchi intrasegmentales, lack cartilage and may divide up to 20-25 times.The final, nonrespiratory, division of a bronchiolus (i.e. sole function is gas conduction) is known as a bronchiolus terminalis. They divide into bronchioli respiratorii which open into sacculi alveolares containing alveoli, via ductus alveolares. Eexternally, each sacculus alveolaris is surrounded by a nest of blood capillaries supplied by small branches of the a. pulmonalis and aa. bronchiales.