Q1. While breathing underwater with scuba equipment, gas is supplied by tank at higher than atmospheric pressure to overcome the extra pressure imposed by the overlying water. Ralph is taking scuba diving classes, and is warned not to hold his breath as ascending from depth but to continuously release air from his mouth. What is the basis of this instruction and what is risk if it is ignored?

Q2. Doris has the obstruction of her right primary bronchus. As a result, how will you expect the oxygen-hemoglobin saturation curve for her right lung to compare with that for her left lung and why give reason?