PADI Divemaster Certification Practice Exam

What type of gas exchange occurs in the lungs regarding inert gases?

1. Instantaneous

2. Gradual

3. Delayed

4. Blocked

The correct answer is: Gradual

The type of gas exchange that occurs in the lungs regarding inert gases is indeed gradual. Inert gases, such as nitrogen, do not elicit any physiological response from the body and are not metabolized. When a diver ascends, the pressure surrounding them decreases, allowing these gases to slowly diffuse out of the body’s tissues and into the lungs. Inert gas exchange is characterized by its gradual nature because it relies on the principles of diffusion, which is the process where molecules move from an area of higher concentration to an area of lower concentration. This means that as the diver ascends and the external pressure decreases, the dissolved inert gases in the blood gradually move into the alveoli in the lungs for exhalation. This is contrasted with other types of gas exchange, which may not involve inert gases or might occur more rapidly due to physiological needs, such as oxygen exchange. Understanding this gradual process is crucial for divers, particularly when it comes to managing ascent rates and decompression procedures to avoid issues like decompression sickness.