Pulmonary Structure and Function

Abstract

The lung and respiratory system arise early in gestation and give rise to an anatomic structure that allows for normal physiologic function. During lung development, disruption can affect normal anatomy and, ultimately, physiology. Neonatal respiratory distress syndrome and BPD are prime examples of how disruption of normal developmental anatomy can have a significant impact on normal lung physiology. It is important to understand how the developing lung and thorax can have effects on pediatric lung disease and normal lung physiology; in that, much of how pediatric lung disease differs from adult lung disease has its roots in developmental anatomy and physiology. It must be appreciated that lung physiology in children differs from adults mainly because lung and chest wall compliance in children is different from adults. Furthermore, understanding how the forces of respiratory system compliance and airways resistance impede ventilation is critical because disease states only augment the factors that impede normal ventilation. This is augmented in children who have smaller airways and more compliant chest walls. Finally, understanding how gas exchange at the acinar level is affected by ventilation (or inadequate ventilation) allows for a better understanding of why patients with lung disease have respiratory insufficiency or failure.