Basic and Clinical Sciences (BCSE) 2025 – 400 Free Practice Questions to Pass the Exam

The type of cells primarily involved in gas exchange in the alveoli are pneumocytes type I. These cells are thin and flat, forming the majority of the surface area of the alveolar wall, which facilitates the efficient diffusion of gases (oxygen and carbon dioxide) between the air in the alveoli and the blood in the surrounding capillaries. Their extensive surface area and minimal thickness are critical for effective gas exchange, making them the key players in this process.

Pneumocytes type II, while also present in the alveoli, serve a different main function. They are responsible for producing surfactant, a substance that reduces surface tension in the alveoli, preventing collapse and aiding in lung compliance. Although they play an important role in alveolar health, they are not primarily involved in the gas exchange process itself.

Clara cells, also known as club cells, are located in the bronchioles and contribute to the secretion of specific proteins and surfactant-like substances but are not involved in gas exchange in the alveoli.

Goblet cells are primarily found in the epithelial lining of the respiratory tract and are responsible for producing mucus. This mucus traps particles and pathogens, playing a role in protecting the airways, but they do not participate in