<prompt> In a preterm baby with respiratory distress syndrome, which type of cell is deficient?Type 1 alveolar cellType 2 alveolar cellAlveolar capillary endothelial cellBronchial mucosal epithelial cell  <response>: Cells in Alveolar Epithelial Lining- Type I pneumocytes-Gas exchange occurs across them. .Cover 93 surface area of alveoli. Type II pneumocytes -synthesize surfactant. Direct indirect injury to type 2 cells lead to ARDS.Cover 5surface area of Alveoli. When there is alveolar injury, type I cells degenerate and are replaced by type II cells. Type II cells are thus responsible for regeneration of epithelium. Type I and type II pneumocytes exist in a ratio of 1:1. Type III pneumocytesact as chemoreceptors.Cover 2 surface area of Alveoli. 