| In the mammalian lung, the blood-air barrier is the site of gas exchange. Oxygen delivered to the blood-air barrier must traverse the barrier, enter the blood, and be transported to the tissues. The barrier consists of TYPE I AND TYPE II CELLS, ALVEOLAR BASAL LAMINA, SEPTAL SPACE (contains macrophages, fibroblasts), THE BASAL LAMINA OF THE ENDOTHELIAL CELL (cell in capillary wall), and the cytoplasm of the ENDOTHELIAL CELL. The two basal laminae can be fused; this creates a thinner and more effective diffusion pathway. The lamellar bodies in type II cells are the source of pulmonary surfactant. |
