What role does elastin play in lung tissue?

Elastin is a crucial protein found in lung tissue that provides the lungs with their elastic properties. Its primary role is to allow the lung to recoil after being stretched during inhalation. When air fills the lungs, the alveoli expand, and the elastin fibers stretch. Once the respiratory muscles relax and air is expelled, elastin enables the lungs to return to their original size and shape efficiently. This recoil is essential for effective exhalation and maintaining proper lung function.

The other choices relate to different aspects of lung physiology. For instance, while elastin contributes to overall lung structure and function, it does not directly increase lung volume or facilitate gas exchange, nor does it enhance ciliary movement, which is primarily the function of other proteins and cellular structures within the respiratory epithelium. Thus, the role of elastin is specifically tied to its ability to allow the lungs to recoil, making the given choice the most accurate representation of elastin's function within lung tissue.