Final answer:
The fetal blood gas barrier is thinner in babies compared to adults, allowing efficient oxygen transfer despite the lower partial pressures of oxygen in the womb.
Step-by-step explanation:
The question pertains to the blood gas barrier's thickness in babies compared to adults. During fetal development, the fetus relies on the placenta and the umbilical cord for the exchange of gases and nutrients. The blood gas barrier in the fetus is essential for the efficient transfer of oxygen from maternal blood to the fetus. The fetal hemoglobin has a greater affinity for oxygen than adult hemoglobin to facilitate this transfer despite lower partial pressures of oxygen. Upon birth, the baby's lungs must adapt quickly to the external environment where they become the site for gas exchange, a process remarkably different from the fetal mechanism.
While this information provides a background on blood oxygenation in the fetus versus adults, it does not directly answer the thickness of the blood gas barrier. It is typically established that the blood-gas barrier is thinner in babies to facilitate the efficient exchange of gases. This adaptational feature allows for sufficient oxygenation of the fetal blood, compensating for the lower oxygen environment in utero compared to the external atmosphere that fully developed lungs will breathe.