Lung is in charge of wei qi (protective qi) which is the first layer of defence of body and closely relevant to skin. External pathogenic factors often attack this layer and show up respiratory and skin conditions.
Lung is just like a water tank to heart. It cools down the heart fire and descends energy to kidney. Many asthma patients have impaired relationship of lung and kidney.
Lung has relationship with large intestine and is the pushing power for transporting and discarding waster materials. Constipation can be treated through regulating lung function.
Lung has its opening in the nose and connects with the throat. Many ENT conditions can find the answer from lungs.
Heat, phlegm, qi disturbance are the major pathologic conditions for this system which needs a holistic approach for treatment.