Transition of respiratory bronchiole to alveolar duct
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
Terminal bronchiole
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
Respiratory bronchiole
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
Alveolar ducts
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
Alveolar sacs
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
Pulmonary vessels
Respiratory bronchioles transition to alveolar ducts, elongated passageways whose walls consist almost entirely of alveoli. The opening of each alveolus is surrounded by a ring of smooth muscle that appears like a knob in cross section. Each respiratory bronchiole branches to form multiple alveolar ducts that end in alveolar sacs. 40X
