Jones & Bartlett Learning (JBL) Module 4A Practice Exam

Gas exchange happens in the alveolar region, where tiny air sacs called alveoli are wrapped by a rich network of alveolar capillaries. The alveolar and capillary walls are extremely thin, so oxygen can diffuse from the air into the blood and carbon dioxide can diffuse from the blood into the air to be exhaled. That makes this region the site where gas exchange occurs, which is why the statement about alveolar capillaries facilitating gas exchange is correct. The idea that the area is primarily cartilage is inaccurate because cartilage supports the larger airways, not the alveoli. Oxygen isn’t produced by cellular respiration; cells use oxygen to generate energy, producing carbon dioxide in the process. Finally, this region isn’t dead space—dead space refers to air in the conducting airways where no gas exchange happens—whereas the alveolar region is specifically designed for gas exchange.