Increased lung compliance is seen in:

Ans: A (Emphysema) Ref: Harrison's 18th edn. pg 2087Explanation:Lung compliance: is defined as change in lung volume for every unit change in pressureCompliance (stretchabilitv) = 1/ elasticity(stiffness)Greater the compliance = easier for the lungs to expandCompliance depends upon = tissue elasticity (25%) + surface tension (75%)Surfactant synthesized by alveolar type 2 cellsIncreased collagen= decrease complianceRestrictive lung disease (fibrosis) = increases collagen= decreases complianceObstructive lung disease (emphysema) = collagen and elasticity decrease = increases complianceCompliance increases with ageLaplaces law states collapsing pressure is inversely proportional to the radius of the alveoliEmphysema: Increased RV & FRCRestrictive lung: Decreased FRC & TLC