Which muscle wraps around respiratory bronchioles and functions to change the diameter of the airway?

Prepare for your Anatomy and Physiology II Exam with our comprehensive exam resources. Utilize flashcards, multiple choice questions with hints, and detailed explanations. Boost your readiness for success!

Smooth muscle is the tissue that wraps around respiratory bronchioles and is responsible for changing their diameter. When smooth muscle contracts, it constricts the airway, increasing resistance to airflow; when it relaxes, the airway widens and resistance decreases. This bronchomotor control is why airway caliber can adjust during stress, exercise, or allergic reactions, and it’s regulated by autonomic signals (parasympathetic input tends to cause constriction, while sympathetic input promotes dilation).

Skeletal muscle isn’t part of the airway walls and governs voluntary movements like coughing or talking rhythms. Cardiac muscle forms the heart’s walls, not the airways. Connective tissue supports structures but doesn’t actively change airway diameter. So the correct choice is smooth muscle.