A 60 yo man comes to GP for cough and sputum production. Has smoked 1 pack daily for 40 yeras. In last two weeks he has notice flecks of blood in sputum. He has painful sensation in his right ring and little finger and a 9 kg weight loss in past four months. Temp is 99 bp is 140/86 resp is 20 pulse is 70. Physical exam shows right eyelid lag, righ pupil is smaller in diameter than left and digital clubbing as well as decreased breath sounds and rales in right upper lung field. A chest x ray shows a 4 cm ill defined peribronchial mass with central cavitaiton lcoated in right upper lung lob. 1. What is likely pathology occuring? 2. What accounts for the symptoms he is presenting with?

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).