Respiratory bronchiole proceed into ?

Respiratory tract anatomyNasal cavity, oral cavity, plarynx and larynx forms upper respiratory tract. Larynx opens into lower respiratory tract which stas from Trachea. Trachea bifurfactes into bronchi (principal bronchi). Progressive branching of bronchi forms bronchioles. Fuher branching of bronchioles leads to terminal bronchioles. Terminal bronchiole emnate into respiratory bronchioles. Respiratory bronchioles proceed into the alveolar ducts, wich immediately branch into alveolar sacs (alveoli).