A 77 yo man with hx of recurrent upper respiratory infections undergoes a left upper lobectomy for squamous cell carcinoma. He has smoked two packs of cigarettes daily for the last 40 years. On microscopic examination, the lung tissue adjacten to the tumor shows destruction of alveolar septae around respiratory bronchioles, markedly enlarged air spaces and prominent athracotic pigment deposition. 1. These findings are most likely compatible with what pathology?

The main function of the respiratory system is gas exchange (O2 and CO2). Ventilation is the movement of air through the respiratory tract into (inspiration) and out of (expiration) the respiratory zone (lungs).