"The alveoli become stronger, creating alterations in ventilation and leading to air trapping due to their size."

"The alveolar-capillary membrane becomes sclerotic and thickens with age, improving gas exchange and reducing lung volume."

"The alveolar walls lose elastic fibers and diminish in thickness, causing the lungs to become more resistant to inflation."

"The alveoli maintain their distensibility, but the increased surface area causes air to move better through the lungs."