Mondo Knows Facts
A soapy film keeps newborn air sacs open
Type II alveolar cells release surfactant that lowers surface tension at birth Without surfactant, the moist lining of each air sac pulls inward and small sacs collapse into larger ones. Surfactant molecules wedge between water molecules at the surface and reduce that pull. Production rises sharply in late pregnancy, which is why premature infants may struggle to keep lungs inflated. It sits in Mondo's human body collection, one of 200 facts that each trace back to the reference below.
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Human lungs have a surface area roughly equal to a tennis courtMillions of tiny air sacs provide massive surface area for gas exchangeThe right lung is larger than the left lungThe left lung features two lobes instead of three to make room for the heartThe diaphragm is the primary muscle responsible for breathingDome-shaped muscle contracts downward to draw air deep into the lungsAn adult breathes in over eleven thousand litres of air dailyHumans take roughly twenty thousand breaths per day under resting conditionsCoughing protects lower respiratory airways from blockagesHigh-pressure air bursts sweep mucus and foreign particles out of lungsPlacental villi create a vast exchange surfaceFinger-like projections bathe in maternal blood to trade oxygen and nutrients
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Tags: lungs, birth, surfactant
A soapy film keeps newborn air sacs open: the short answers
- Where does this come from, and can I check it?
- Type II alveolar cells release surfactant that lowers surface tension at birth. The figure is taken from NHLBI, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
- Is this really a human body fact?
- Yes. It sits on the Human Body shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
- What else can I read about it?
- The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.