What is bronchoconstriction?

Bronchoconstriction refers specifically to the narrowing or constricting of the bronchi, which are the large air passages that lead from the trachea to the lungs. This physiological response can occur due to various factors, such as exposure to allergens, irritants, or during an asthma attack. When the bronchi constrict, it can result in difficulty breathing, wheezing, and reduced airflow in and out of the lungs.

The other options describe processes that are opposite to bronchoconstriction or unrelated to the concept. Widening of the bronchial passages corresponds to bronchodilation, which increases airflow, while inflation of lung tissues pertains to the expansion of the lungs during inhalation. Dilating blood vessels is a cardiovascular reaction that does not directly impact the bronchial passages. Thus, recognizing that bronchoconstriction is inherently about the narrowing or blockage of the bronchi helps solidify the understanding of respiratory responses in various medical conditions.