Certified Transport Registered Nurse Certification Practice Exam

In breathing mechanics, which gas law relates changes in lung volume to changes in pressure?

1. Graham's Law

2. Henry's Law

3. Boyle's Law

4. Charles' Law

The correct answer is: Boyle's Law

The correct choice is Boyle's Law, which states that at a constant temperature, the pressure of a gas tends to decrease as the volume of the gas increases, and vice versa. In the context of breathing mechanics, this principle is fundamental to understanding how the lung volume changes during inhalation and exhalation. When the diaphragm contracts during inhalation, the volume of the thoracic cavity increases, leading to a decrease in pressure within the lungs as it becomes less than the atmospheric pressure outside. This pressure difference causes air to flow into the lungs. Conversely, during exhalation, when the diaphragm relaxes and the thoracic cavity volume decreases, the pressure inside the lungs increases, and air is pushed out. Boyle's Law is critical for explaining the mechanical processes of breathing, including how airflow is generated in response to pressure changes within the lungs. Understanding this relationship is essential for nurses involved in patient transport, as they must be aware of respiratory mechanics when providing care. Graham's Law pertains to the rates of diffusion of gases, while Henry's Law relates to the solubility of gases in liquids. Charles' Law involves the relationship between gas volume and temperature, which is not directly applicable to the mechanics of lung volume changes and pressure during respiration