Describe the physiological factors that affect pulmonary arterial pressure (65% of marks). Write short notes on the use of inhaled nitric oxide as a pulmonary vasodilator (35% of marks).
Pressure in a system is generated by the interaction between flow and resistance. A structured
approach to defining and describing the many factors that influence fluid flow and resistance
was required to score well. Poiseuille’s law describes the determinants of resistance to laminar
fluid flow and provides a useful answer structure. It is also necessary to describe factors that
determine flow. This includes factors that determine venous return, as well right and left heart
A standard structured answer to the pharmacology of nitric oxide enabled concise and high
scoring answering of this question.