Question

Explain why the concepts of partial pressures and partial pressure gradients are so critical to understanding how the entire respiratory system functions. Use specific examples from various parts of the overall respiratory process to support your answer.

Answer 1

Diffusion is the process of movement of molecues from a region of higher concentration to a region of lower concentration.The factors that determining how rapidly the respiratory gases will pass through the respiratory membrane includes the diffussion and the partial pressure of gases across the respiratory membrane.

Partial pressure is defined as the individual pressure from each gas in a mixture.If we consider air as the mixture here, then Oxygen is 20.93% of the mixture , CO2 is 0.03% and nitrogen is 79.04%.This creates a pressure gradient that causes gaseous exchange.

According to Henry's law, the amount of a specific gas that dissolves in a liquid is a function of its partial pressure.The partial pressure of oxygen is high in the alveoli and it is low in the blood of the pulmonary capillaries. Hence, oxygen diffuses across the respiratory membrane from the alveoli into the blood.