Florida State Paramedic Practice Exam

What is the term for the process of gas exchange that occurs in the lungs?

1. Osmosis

2. Diffusion

3. Filtration

4. Absorption

The correct answer is: Diffusion

The correct term for the process of gas exchange that occurs in the lungs is diffusion. In the context of the respiratory system, diffusion refers to the movement of gases, specifically oxygen and carbon dioxide, across the alveolar membrane. This process takes place due to differences in partial pressures of these gases in the air inside the alveoli and the blood in the surrounding capillaries. Oxygen, present in higher concentration in the alveoli, diffuses into the blood, where it is in lower concentration. Conversely, carbon dioxide, which is in higher concentration in the blood, diffuses into the alveoli to be exhaled. This mechanism is essential for gas exchange and the maintenance of adequate oxygen levels in the bloodstream while removing carbon dioxide, a waste product of metabolism. The other terms do not accurately define this process: osmosis involves the movement of water across a semipermeable membrane, filtration pertains to the separation of particles from a fluid based on size, and absorption refers to the uptake of substances by cells or tissues, such as nutrients in the digestive system. Understanding diffusion in the respiratory system is crucial for comprehending how the body maintains homeostasis in terms of gas exchange.