Gas Exchange across Respiratory Surfaces

Gas pressures in the atmosphere and body determine gas exchange: both O₂ and CO₂ will flow from areas of high to low pressure.

The purpose of respiration is to perform gas exchange, a process that involves ventilation and perfusion and that relies on the laws of partial pressure.

Lung volumes measure the amount of air for a specific function, while lung capacities are the sum of two or more volumes.

Differences in partial pressures of O₂ create a gradient that causes oxygen to move from the alveoli to the capillaries and into tissues.