Respiratory system is referred to the system which is responsible for inhaling oxygen from exterior, carrying it through the blood to all parts of the body, receiving carbon dioxide from the tissues, carrying it through the blood to the lungs and exhaling it to the exterior. Use the following links to jump directly to the articles on respiratory system–

Bronchial Asthma
Chronic Obstructive Pulmonary Diseases (COPD)
Pleural effusion