Final answer:
Type 2 cells, also known as cuboidal epithelial cells, secrete surfactant to reduce surface tension in the alveoli and prevent their collapse. Insufficient production of this surfactant, especially in premature infants, can lead to difficulty inflating the lungs.
Step-by-step explanation:
Type 2 cells are cuboidal epithelial cells that secrete surfactant to prevent the alveoli from collapsing. These cells are important for maintaining the function of the alveoli in the lungs. Pulmonary surfactant, a substance composed of phospholipids and proteins, is crucial for reducing the surface tension of the alveoli, which if unopposed, can lead to alveolar collapse during exhalation. Without sufficient surfactant, as might be the case in premature infants, difficulty inflating the lungs can occur due to the high surface tension. Type II alveolar cells are interspersed among type I alveolar cells, which are squamous epithelial cells responsible for gas exchange and comprise the majority of the alveolar surface area. Alveolar macrophages are also present in the alveoli, serving as an immune defense by removing debris and pathogens.