What is one respiratory effect of sympathetic nervous system stimulation?

Sympathetic nervous system stimulation primarily leads to bronchodilation, which enhances airflow by relaxing bronchial smooth muscles and enlarging the air passages. This physiological response is mediated by the release of catecholamines, such as adrenaline, that bind to beta-adrenergic receptors in the lungs, promoting airway relaxation.

Mucus mobilization is a secondary effect of sympathetic stimulation. When the airways are dilated, there is improved movement of mucus due to increased airflow and enhanced clearance mechanisms. This can help reduce the risk of airway obstruction by ensuring that mucus does not build up in the bronchial passages.

In contrast, bronchoconstriction, reduced airflow, and increased airway resistance are generally associated with parasympathetic nervous system activity. The parasympathetic system prompts bronchial smooth muscle contraction and stimulates mucus secretion, which can lead to inflammation and increased airway resistance. Therefore, the stimulation of the sympathetic nervous system plays a critical role in promoting airway patency and facilitating mucus movement, particularly in response to stress or physical activity.