The lungs consist of spongy tissue filled with air spaces called alveoli when a person exhales the alveoli would collapse into each other and form larger air sacs with less surface area. Babies that are born prematurely do not have enough surfactant to breathe normally at birth and are said to have infant respiratory distress syndrome. In the lungs, surfactant reduces the surface tension of fluid in the lungs, which helps to maximize the surface area available for gas exchange, equalize the pressures between large and small air spaces and make the small air sacs in the lungs (alveoli) more stable by keeping them from collapsing when a baby exhales.
Answer: The alveoli are lined with water molecules, which are attracted to one another and tend to move closer together, making the alveoli collapse. Surfactant molecules get in between the water molecules, keeping them apart.
Explanation: Pearson Lab: Respiratory System A&P 2.
