ELi5: When a baby is born, how are their lungs instantly able to breathe air if they haven’t been breathing air for 9 months?
In: Biology
This is partially d/t a substance called surfactant. Surfactant prevents the moisture on the walls of the lungs from sticking together by breaking the surface tension. Without it, lungs will remain collapsed and won’t allow air to inflate them properly.
A fetus doesn’t produce surfactant until 26 weeks. Therefore, infants born premature prior may need supplementation in order to breathe properly.
Here is a fun, safe, experiment to simulate how surfactants work:
1) Fill a bowl with some tap water.
2) Then sprinkle ground pepper on the water’s surface. If your bowl is clean, you should see the pepper sticking to the surface of the water.
3) Then put a tiny dab of dish soap on your index finger. Next, put your finger in the bowl. The dish soap acts as a surfactant breaking the surface tension, allowing the pepper to fall to the bottom of the bowl.
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