9.8. Applying Anatomy
Surgical procedures of the lungs
- Pneumonectomy – the removal of an entire lung.
- Lobectomy – the removal of a lobe of the lung.
- Segmental resection – removal of a bronchopulmonary segment.
Choking is an airway obstruction that prevents ventilation of the lungs and therefore gas exchange. If the airway is not cleared, respiratory and cardiac arrest are likely. In the cardiac arrest scenario, advice is normally to begin chest compressions for CPR. A bystander may worry that the chest compressions and rescue breaths will push the obstruction further down the trachea, making the situation worse. However, this is not necessarily the case – at the carina, the obstruction is more like to enter the right primary bronchus (because it is wider and more vertical than the left). If this occurred, the left bronchus would be cleared and the left lung could be ventilated, facilitating gas exchange.
This might be seen in a person with a thoracic stab wound. The tension pneumothorax occurs when air enters the pleural cavity from the atmosphere, yet it does not leave because the skin and clothing form a one-way valve. This results in a build-up of air (and pressure), causing the lung of that side to collapse, and the mediastinum shifting to the opposite side, compressing that lung.
The alveolar walls contain a protein called elastin. Once the lungs are filled with air at the end of inspiration, the elastin allows a considerable recoil action to take place and forces the air out through the airways during expiration. As such, during normal, quiet breathing, the process of expiration is mainly passive with few muscles involved.