A 58 year old women comes to physician due to 6 month history of increasing SOB and a dry hacking cough. Patient is afebrile. Physical exam of her fingers shows clubbing. When asked to stand she becomes increasingly dyspneic. Auscultation is notable for fine bibasilar inspiratory crackles heard over the lung fields. Patient has no known pertinent past lung history. Arterial blood gas studie show hypoxia. Pulmonary function tests show decreased froced vital capacity, decreased forced echalation in one second, normal FEV1/FVC ration and decreased diffusing capacity for carbon monoxide. 1. What is your likely diagnosis and why? 2. What would be seen on lung biopsy?

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).