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' jtactanl Effecls

RESPIRATORY PHYSIOLOGY

Drop of water with surface tension of 72 dynes/cm forms

Drop of water mixed with household detergent; surface tension reduced to 20 dynes/cm and thus water spreads out

Figurę 5.18 Surfactant Effects

Surfactant is produced by lype II alveolar cells (see Figurę 5.14). Its major component is the phospholipid dipalmitoyl phosphatidyl-cboline. It acts to reduce the surface tension of the fluid-lined alveoti isee also Figuro 5.10). Thus. Iower pressures aro rorjuirod to mflatc the alveoli. Failure to produce sufficient amounts of surfactant. as can occur in premature infants, results in an inaease in the work of breathing and respiratory distress.

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