Final answer:
The respiratory membrane is a thin wall between the alveolar lumen and the blood. It facilitates gas exchange through simple diffusion between the alveoli and the blood in the pulmonary capillaries.
Step-by-step explanation:
The respiratory membrane is the thin wall between the alveolar lumen and the blood. This membrane is crucial for the process of gas exchange, where oxygen enters the blood and carbon dioxide is released from the blood into the alveolar air. The respiratory membrane comprises the alveolar epithelium and the endothelium of the surrounding capillaries. These two layers together create a blood-air barrier that enables gas exchange via simple diffusion.
The respiratory membrane is the thin wall between the alveolar lumen and the blood. The respiratory membrane is formed by the alveolar epithelium and the endothelium of the surrounding capillaries. It serves as a blood-air barrier through which gas exchange occurs by simple diffusion. This allows for oxygen to be picked up by the blood and carbon dioxide to be released into the air of the alveoli.