During an asthma attack, what pathophysiological process leads to the wheezing sound?

A. Overproduction of surfactant: Surfactant is a lipoprotein that reduces surface tension in the alveoli to prevent their collapse. An overproduction would not lead to the musical whistling sound of wheezing. Asthma is a disease of the conducting airways, not a primary disorder of surfactant production or alveolar tension. B. Airway narrowing due to bronchospasm: During an attack, inflammatory triggers lead to the contraction of bronchial smooth muscle and mucosal edema. This narrows the lumen of the bronchioles, creating high-velocity, turbulent airflow as air is forced through the constricted passages. This turbulence produces the characteristic high-pitched wheezing sound. C. Accumulation of fluid in the alveoli: Fluid in the alveoli, such as in pulmonary edema, typically produces crackles or rales during auscultation. Wheezing is specifically associated with the narrowing of the airway pipes, not the filling of the air sacs. The pathology of asthma focuses on the bronchial tubes. D. Thickening of alveolar walls: Thickening of the alveolar-capillary membrane is characteristic of restrictive lung diseases like interstitial fibrosis. While it impairs gas exchange, it does not mechanically cause the expiratory wheezing seen in obstructive diseases like asthma. Asthma's primary defect is reversible airway obstruction and inflammation.