The main function of the sympathetic innervation on the lungs is ______.

• A. to cause bronchodilation
• B. to decrease respiratory rate
• C. to constrict the bronchioles
• D. to stimulate mucus secretion

Answer: (A)

Verified step by step guidance

1. Step 1: Understand the role of the sympathetic nervous system in the body. The sympathetic nervous system is part of the autonomic nervous system and is responsible for the 'fight or flight' response, which prepares the body for action during stressful situations.
2. Step 2: Recall the effects of sympathetic activation on the lungs. During a 'fight or flight' response, the body needs increased oxygen delivery to tissues, which is achieved by bronchodilation (widening of the airways) to allow more air to flow into the lungs.
3. Step 3: Analyze the options provided in the question. Bronchodilation aligns with the sympathetic nervous system's role in increasing airflow, while the other options (decreasing respiratory rate, constricting bronchioles, and stimulating mucus secretion) are not consistent with the 'fight or flight' response.
4. Step 4: Eliminate incorrect answers. Decreasing respiratory rate and constricting bronchioles would reduce oxygen intake, which is counterproductive during stress. Stimulating mucus secretion is more associated with parasympathetic activity, not sympathetic.
5. Step 5: Conclude that the correct answer is 'to cause bronchodilation,' as this is the primary function of sympathetic innervation on the lungs during a stress response.