The lungs

The lungs are divided into a left lung and a right lung which take in oxygen during inhalation and expel carbon dioxide. Incoming air passes through the trachea into the bronchial tubes, which branch off into smaller and smaller bronchial tubes before finally ending in the pulmonary alveoli. This structure is known as the bronchial tree. The pulmonary alveoli are surrounded by tiny blood vessels which have very thin membranes to allow oxygen to be absorbed and carbon dioxide to be released.

Medical conditions that may lead to transplantation

The following conditions may necessitate a lung transplant: cystic fibrosis, pulmonary emphysema, pulmonary hypertension and also rarer afflictions such as sarcoidosis and inhaling certain types of toxins. Patients who require a live-saving lung transplant are no longer able to manage day-to-day activities and are dependant on oxygen therapy. Lungs can be transplanted individually or, as is more common, in pairs.