Lung surfactants are made from animal lung extract and contain phospholipids. Natural surfactant is produced by the alveolar cells in the lungs and line mainly the alveoli and small bronchioles, and prevents the alveoli from collapsing. Lung surfactant makes it easier for oxygen to penetrate the lung surface lining and move into the blood. As an infant takes their first breath, the blood vessels around the lungs get wider and your babys blood flows to the lungs to collect oxygen. Babies and toddlers lung development from 0-3 years adult lungs have around 300 million air sacs. If your baby is a preemie, youll have plenty of questions about how to give her the extra care she needs. A lot depends on how many weeks before her due date shes born. The best way to prevent lung problems in a preterm baby is to avoid a premature. These drugs can help speed up the process of lung development. In general, most babies born at 35 weeks will have adequate functioning lungs and babies have traditionally been considered full-term with normally-developed lungs by 37 weeks.