Final answer:
Obstruction in the major respiratory passages can be due to inflammation, congestion, blockage, or narrowing. Conditions like emphysema and asthma lead to these obstructions by damaging lung tissues or triggering inflammation and muscle spasms in the airways.
Step-by-step explanation:
The obstruction that can occur in the major passages of the respiratory system can be due to several factors such as inflammation, congestion, blockage, or narrowing. Obstructive diseases and conditions, including emphysema, asthma, and pulmonary edema, usually involve these types of obstructions.
In emphysema, primarily caused by smoking, the alveolus walls are damaged, reducing gas exchange surface area and leading to air being trapped due to decreased lung elastic recoil. In asthma, environmental factors trigger inflammation, which can lead to obstruction from edema, smooth muscle spasms (bronchoconstriction), increased mucus production, and potentially epithelial damage. These factors prevent proper movement of gases, causing those with obstructive diseases to breathe at higher lung volumes to compensate for their impaired airways.
Pulmonary obstruction can also occur due to biliary tree obstruction, where a blockage in the bile ducts causes jaundice. Regardless of the specific cause, obstructive pulmonary diseases reduce the effectiveness of ventilation and gas exchange.