Final answer:
The movement of respiratory gases obeys the laws of diffusion, moving from high to low partial pressures. Oxygen and carbon dioxide exchange across the alveoli via this principle, guided by Dalton's and Henry's laws, ensuring homeostasis of blood gases and pH levels.
Step-by-step explanation:
The movement of respiratory gases aligns with the laws of diffusion, where molecules move from an area of higher concentration to an area of lower concentration until equilibrium is reached.
The principle that governs their direction is based on partial pressure gradients of each gas. Oxygen (O₂) and carbon dioxide (CO₂) diffuse according to this gradient from areas of high partial pressure to areas of low partial pressure.
Gas exchange across the alveoli is a perfect example that demonstrates this principle. The partial pressure of oxygen is higher in the alveoli than in the blood of the pulmonary capillaries, which facilitates the diffusion of oxygen into the blood.
Conversely, the partial pressure of CO₂ is higher in the pulmonary capillaries compared to the alveoli, promoting the diffusion of CO₂ from the blood into the alveoli. This exchange keeps the homeostasis of blood gases and pH levels balanced, which is crucial for our bodies to function properly.
The behavior of gases during this process is also described by Dalton's and Henry's laws, asserting that gases in a mixture exert partial pressures independently and that the amount of gas dissolving in a liquid is directly proportional to its partial pressure, respectively.