Final answer:
Type II alveolar cells are responsible for secreting surfactant, which decreases the surface tension in the alveoli to prevent collapse, particularly during exhalation.
Step-by-step explanation:
The cell type responsible for secreting surfactant that reduces the tendency for pulmonary alveoli to collapse is the type II alveolar cell. These cells are cuboidal epithelial cells that are a minor component of the alveolar wall. Unlike type I alveolar cells, which are squamous epithelial cells that make up the majority of the alveolar surface and are highly permeable to gases, type II alveolar cells have the specific function of secreting pulmonary surfactant. This surfactant is composed of phospholipids and proteins that decrease the surface tension within the alveoli, thus preventing alveolar collapse, which is especially crucial during expiration, when the lungs are at more risk of collapsing.
In the context of a prematurely born baby, insufficient production of surfactant from type II alveolar cells can lead to difficulty in inflating the lungs due to increased surface tension in the alveoli. This is because surfactant reduces surface tension, allowing the alveoli to remain open and functional. Without adequate surfactant, the infant may suffer from respiratory distress syndrome, highlighting the critical role of type II alveolar cells in pulmonary function.