What is the primary role of a bronchodilator?

The primary role of a bronchodilator is to relax respiratory muscles, which enables the airways to open more fully. This action is crucial for patients suffering from respiratory conditions such as asthma or chronic obstructive pulmonary disease (COPD), where constricted air passages can lead to difficulty breathing and reduced airflow. By widening the airways, bronchodilators facilitate easier passage of air in and out of the lungs, enhancing oxygen intake and improving breathing efficiency.

In contrast, inhibiting sodium reabsorption relates more to kidney function and managing fluid balance, thus not relevant to respiratory therapy. Increasing bowel movements pertains to medications like laxatives, which serve a completely different purpose in gastrointestinal health. Similarly, suppressing cough could involve different medications aimed at controlling cough reflexes but does not address the fundamental issue of airway constriction that bronchodilators target. Therefore, the correct answer highlights the specific function of bronchodilators in respiratory care.