Final answer:
A deficiency in surfactant, composed of phospholipids and lipoproteins, increases alveolar surface tension, which can lead to atelectasis. This substance is crucial for reducing surface tension in the alveoli, allowing them to function properly.
Step-by-step explanation:
An increase in alveolar surface tension leading to atelectasis is caused due to a deficiency in surfactant, which is made of phospholipids and lipoproteins and is seen in the terminal bronchiole region of the bronchiole that attaches to the respiratory bronchioles.
Surfactant is a detergent-like liquid in the airways that serves to lower the surface tension of the alveoli, allowing them to expand during inhalation and not collapse during exhalation. Without adequate surfactant, the surface tension within the alveoli would be too high, leading to the collapse of these air sacs and compromised lung function.