Of the components of the bronchial tree, which represents the greatest surface area? Select one:

a. Bronchi

b. Respiratory bronchioles

c. Alveolar ducts

d. Alveolar sacs

Answer;

D. Alveolar sacs

Explanation;

-The bronchial tree is the branching system of trachea, bronchi, bronchioles, alveolar ducts, alveolar sacs, and alveoli that conducts air from the windpipe into the lungs.

-The alveoli allow this gas exchange to occur. Each alveoli has a network of capillaries that carry oxygen-poor red blood cells. The capillaries bring the red blood cells very close to the air space in the alveoli. The air in the alveoli is oxygen rich.

-Oxygen moves from the alveolar space into the red blood cell by diffusion. This can happen very quickly because the surface are of the alveoli is large and the membranes separating the lungs from the red blood cells are very thin.