AEMCA Practice Exam

What physiological change occurs with nitrogen bubbles during decompression?

1. The volume of nitrogen bubbles decreases

2. Gas diffuses back into the lungs

3. Volume of nitrogen bubbles increases

4. Oxygen levels increase in the blood

The correct answer is: Volume of nitrogen bubbles increases

During decompression, as a diver ascends from depths where they have been exposed to increased pressure, the surrounding pressure decreases rapidly. This reduction in pressure can lead to a physiological change involving nitrogen bubbles that have formed in the body’s tissues. When a diver is at depth, nitrogen from the compressed air they are breathing dissolves into the body tissues under pressure. As they ascend, the nitrogen begins to come out of solution due to the decreasing pressure. If the ascent is too rapid, this can cause the nitrogen to nucleate, forming bubbles. Consequently, the volume of these nitrogen bubbles increases as they come out of solution and expand, leading to potential complications such as decompression sickness, or "the bends." Understanding this process is crucial for recognizing the risks associated with diving and the importance of controlled ascent rates to allow for the safe diffusion of nitrogen back into the lungs and out of the body, rather than forming bubbles in the tissues. The physiological change of increasing bubble volume during decompression is a key concept in understanding the body's response to pressure changes in diving scenarios.