MediumZoologyBreathing and Exchange of Gases
+4 / -1
Surfactant in the lungs is secreted by which cells?
A
Type I alveolar cells (pneumocytes)
B
Type II alveolar cells (pneumocytes)
C
Clara cells
D
Goblet cells
Explanation
Surfactant (surface active agent) is a lipoprotein mixture primarily composed of dipalmitoylphosphatidylcholine (DPPC), secreted by Type II alveolar pneumocytes. It reduces surface tension within alveoli, preventing their collapse (atelectasis) during expiration. Deficiency of surfactant in premature infants causes neonatal respiratory distress syndrome (hyaline membrane disease).
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