<prompt> Ture about terminal bronchioles are all except ?Absence of cailagePresence of clara cellsAbsence of smooth musclesAbsence of submucous glands  <response>: Terminal bronchioles contain Clara cells which secrete a protein that lines the small air passages. Alveoli alveolar sac are lined by type 1 pneumocytes 95 and type 2 pneumocytes 5. Type 2 pneumocytes secrete surfactant and also helps in repair of alveoli after destruction of type- 1 pneumocytes. Pores of Kohn are present in alveolar wall to allow passage of bacteria and exudate between adjacent alveoli.Terminal bronchi contain maximum smooth muscle cells relative to wall thickness.Cailage is found in larynx, trachea and bronchi but not in bronchioles.Submucosal glands are paicularly numerous in medium-sized bronchi and disapperar in distal terminal bronchioles. 