What is the term for a decrease in the diameter of a bronchus or bronchiole?

The correct term for a decrease in the diameter of a bronchus or bronchiole is bronchoconstriction. This physiological process involves the contraction of the smooth muscle lining the airways, leading to a narrowing effect that restricts airflow during respiration.

Bronchoconstriction can occur in response to various stimuli, including allergens, irritants, or as part of an asthma attack, resulting in difficulty breathing. Understanding this term is crucial in the context of respiratory physiology and conditions that affect airflow, as it highlights the importance of airway diameter in the regulation of respiratory function.

In contrast, bronchodilation refers to the widening of the airways, which is opposite to bronchoconstriction and helps increase airflow. Alveolar expansion relates to the increase in size of the alveoli during inhalation and does not directly pertain to the diameter of bronchi or bronchioles. Airway resistance is a broader term that encompasses factors affecting airflow in the respiratory system, but it does not specifically describe the decrease in diameter.