Which of the following statements about respiratory distress syndrome RDS is true?
|A||It is unrelated to the baby's premature birth.|
|B||It is a consequence of too few Type II pneumocytes.|
|C||The lecithin/sphingomyelin ratio in the amniotic fluid is likely to be greater than two.|
|D||The concentration of dipalmitoylphosphatidylcholine in the amniotic fluid would be expected to be lower than that of a full-term baby.|
DipalmitoylphosphatidylcholineDPPC, or dipalmitoyl lecithin is the lung surfactant found in mature, healthy lungs. RDS can occur in lungs that make too little of this compound. If the lecithin/sphingomyelin ratio in amniotic is greater than two, a newborn's lungs are considered to be sufficiently mature—premature lungs would be expected to have a ratio lower than two. The RDS would not be due to too few Type II pneumocytes—these cells would simply be secreting sphingomyelin rather than DPPC.