A 32 year old man comes to GP because he injured himself at work and has tender ribs. His temperature is 37.2, pulse is 74 min, respirations are 18 min and BP is 126/78. On review of systems, he states he has developed occasional fatigue, episodes of cough and sinus congestion and exertional dyspnea in the past year. He recalls an episode approximately 1 year ago in whch he experience fever, ankle swelling and tender red bumpts on his legs. At that time, he denied having an infectio nor trauma to the legs. He is a former smoker, of and on for a few years. X ray shows hilar lymphadenopathy 1. What is the likely pathology and why do you think this?

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).