Final answer:
The respiratory membrane is a thin barrier that allows for the efficient exchange of gases such as oxygen and carbon dioxide between the lungs and blood through the process of simple diffusion across alveoli and capillary walls.
Step-by-step explanation:
The respiratory membrane is a thin barrier (0.2 μm) that allows for the efficient exchange of gases between the lungs and the blood. Comprised of the simple squamous epithelium formed by type I alveolar cells, this membrane is attached to a thin, elastic basement membrane, and becomes borderless with the endothelial membrane of capillaries. When taking into account both the alveoli and capillary membranes, the combined respiratory membrane is approximately 0.5 μm thick. This structure facilitates the simple diffusion of gases, where oxygen is absorbed into the blood for transport and carbon dioxide (CO2) is expelled into the air of the alveoli.
Each alveolus in the lung is lined with a network of capillaries which are instrumental in this gas exchange process. With an extensive surface area within the lungs and a highly permeable membrane to gases, the conditions are ideal for the respiratory membrane to function effectively. In addition, lung tissue contains numerous alveoli, providing a vast surface area analogous to half a tennis court, which is crucial for pulmonary gas exchange. This process of oxygen entering the blood and carbon dioxide leaving is vital for respiration and the overall functioning of the respiratory system.