or convection
In physiology, the mechanism responsible for movement of air from the atmosphere into the lungs and for movement of blood between the lungs and the tissues.
It is one of two principal mechanisms of exchange by which oxygen and carbon dioxide move between the environment and the tissues, the other being diffusion . Local flows (e.g., through skeletal muscles during exercise) can be increased selectively, increasing the exchange of gases between tissue cells and the capillaries.