Final answer:
Boyle's law states that pressure and volume of a gas are inversely proportional, and it is crucial to pulmonary ventilation, as it explains airflow during respiration. During inspiration, lung volume increases and pressure decreases, causing air to flow in. During expiration, lung volume decreases and pressure increases, leading to air expulsion.
Step-by-step explanation:
Boyle's Law and Pulmonary Ventilation
Boyle's law is a principle in physics and chemistry stating that for a given mass of gas at a constant temperature, the volume of the gas is inversely proportional to the pressure. This means that as the volume increases, the pressure decreases, and vice versa. This law is directly applicable to the process of pulmonary ventilation, which includes the cycles of inspiration and expiration.
Inspiration at Rest
During inspiration (inhalation), the diaphragm and intercostal muscles contract, leading to an enlargement of the chest cavity. As a result, the lung volume increases, and according to Boyle's law, the pressure inside the lungs decreases. Consequently, air flows into the lungs from the higher atmospheric pressure outside to the lower pressure inside the lungs.
Expiration at Rest
Conversely, during expiration (exhalation), the diaphragm and rib muscles relax, causing the chest cavity to become smaller. The lung volume decreases, leading to an increase in pressure inside the lungs. Following Boyle's law, air is then expelled from the lungs as it moves from the area of higher pressure inside to the lower atmospheric pressure outside.