What constitutes the respiratory membrane? A. the parietal and visceral pleurae and enclosed pleural fl uid B. capillary and alveolar epithelial cells, their basement membranes and adja- cent fl uid C. the alveolar surface fl uid and epithelial cells D. alveolar epithelial and septal cells, ciliated cells, macrophages and surfactant.
Option B. Capillary and alveolar epithelial cells, their basement membranes and adjacent fluid constitutes the respiratory membrane.
