Since it's mostly under parasympathetic control that can cause bronchoconstriction, was Nature's purpose to be on guard for toxins (smoke, gases, water) that might enter the lungs? I understand that the sympathetic contribution is bronchodilation but that is done only during brief episodes of "fight or flight" making it the default system. Is there an equivalent amphibian application that could serve to amplify this conundrum? Thank You All!