In a preterm baby with Respiratory distress syndrome, which type of cell is deficiency?
Cells in Alveolar Epithelial Lining- Type I pneumocytes-Gas exchange occurs across them. .Cover93%surface area of alveoli. Type II pneumocytes -synthesizesurfactant. Direct / indirect injury to type 2 cells lead to ARDS.Cover 5%surface 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.
Type 1 alveolar cell
Type 2 alveolar cell
Alveolar capillary endothelial cells
Bronchial mucosal epithelial cell
NEET Jan 2020