Final answer:
The triangle symbol Δ in the formula for airflow in the lungs signifies the difference in pressure, which is the driving force for air to move through the respiratory system.
Step-by-step explanation:
The triangle symbol Δ in the formula F = ΔP / R, which describes airflow in the lungs, stands for the difference in pressure between two points. In the context of pulmonary physiology, this pressure difference is the driving force for airflow. The flow (F) is directly proportional to the difference in pressure (ΔP) and inversely proportional to resistance (R). Resistance in the lungs is often affected by the size of the airways, with smaller diameters increasing resistance due to a higher frequency of air molecules colliding with the walls.
The concept of pressure difference is also reflected in Boyle's law, which indicates that a gas's pressure decreases as the volume increases. Resistance affects how easily air flows through the lungs, and surface tension within the alveoli plays a role in lung mechanics too. Surfactant in the lungs reduces surface tension, facilitating breathing.