The Main Mechanism by Which Ephedrine Helps in the Treatment

Multiple Choice

The main mechanism by which ephedrine helps in the treatment of asthma is that it

A) causes the smooth muscles surrounding bronchial passages to relax.
B) increases tension in the smooth muscles surrounding bronchial passages, thus increasing responsiveness of these muscles to demand.
C) increases the blood flow from the heart to the lungs by stimulating release of norepinephrine.
D) decreases heart rate and the force with which it pumps.