PADI Divemaster Certification Practice Exam

If a diver descends to a specific depth and remains there long enough, what will happen to nitrogen in their tissues?

1. The tissues will excrete nitrogen

2. The tissues will stop absorbing nitrogen

3. The tissues will saturate with nitrogen

4. The tissues will absorb oxygen instead

The correct answer is: The tissues will saturate with nitrogen

When a diver descends to a specific depth, the increased pressure causes nitrogen, which is absorbed from the air we breathe, to dissolve into the body’s tissues. The physiological process of this nitrogen absorption is known as "saturation." At a given depth, if the diver remains there long enough, the tissues will reach a state of equilibrium, absorbing nitrogen until they are saturated with it. This saturation happens because the partial pressure of nitrogen in the surrounding environment (the water) is higher than in the diver's blood and tissues. As the diver stays at that depth, nitrogen continues to diffuse into the tissues until the rate of absorption equals the rate of elimination, resulting in a balance known as saturation. Understanding this concept is critical for divers, especially in relation to avoiding decompression sickness (DCS), which can occur when returning to the surface too quickly without allowing the nitrogen absorbed in the tissues to safely leave the body.