cardiovascular system

In myogenic mechanism when a transmural pressure increase blood vessel constrict to regulate the flow In stress relaxation when pressure increases blood vessels dilate to accommodate extra blood. So what happens to vessel radius when pressure increases?

We learn that the stroke volume is the same for the right and left side of the heart. So the amount of blood in either circulations should also be the same. (is it? I myself doubt this statement. As in, does it need to?)There's also a list of adaptations in the pulmonary vasculature that...