<prompt> Pneumatocytes lines theSegmental bronchioleTerminal branchiolesRespiratory bronchiolesAlveoli  <response>: Alveoli 83-M. Kaul histology 3rd 221- LB.Singh 5thRespiratory system - Histology Trachea - lined by pseudostratified ciliated columnar epithelium Intrapulmonary Bronchus - lined by pseudostratified ciliated columnar epithelium Terminal Bronchiole - lined by simple columnar epithelium Respiratory Bronchiole - lined by cuboidal epithelium Atria, alveolar ducts and alveoli - lined with squamous epitheliumALVEOLI - The main support of the alveoli is provided by elastic fibres Majority of cells lining the alveoli are the squamous cells or type 1 pneumocytes. Few are larger cells or type II pneumocytes. Type II cells secrete the surfactant which lowers surface tension and prevents alveoli from collapsing The exchange between the blood in the capillaries and air in the alveoli takes place througha Cytoplasm of endothelial cell of a capillaryb Basement membrane of the capillaryc Basement membrane of the alveolusd Cytoplasm of the epithelial cells of the alveolus In CHF, heart failure cells are present in the sputum. These cells are the alveolar macrophages, containing hemosiderin of the red blood cells from the ruptured capillaries. 