The alveolar epithelial lining undergoes cell division
into type I and type II pneumocytes. Which of the
following correctly describe the pneumocytes?
I. Type I pneumocytes account for more than 97%
of the alveolar surface area.
II. Type II pneumocytes form a gas-permeable mem-
brane for diffusion of gases.
III. Surfactant production occurs in the lamellar bodies
of type II pneumocytes, which release surfactant by
IV. Type I pneumocytes are responsible for surfactant
production and storage.
V. Type I pneumocytes are squamous shaped and
optimized for gas exchange; type II pneumocytes
are cube shaped and may differentiate into
type I cells.
A. I, II, IV, and V
B. I, III, and V
C. I, IV, and V
D. II, IV, and V
E. III and IV