Both respiration and breathing are essentially physical processes. Air and/or various gases are moved from one place to another. Their movement is because of differences in their relative pressures from one space to another.
FAQ Pressure Gradient:
Consider a situation in which there are two separate but connected spaces. If the concentration or pressure of that substance is greater in one space than the other, then there is a pressure gradient for that substance. As a result, the substance will move from the area of higher pressure to the area of lower pressure.
FAQ Gas Laws:
Assume that we have a container and we can change the volume of the container without allowing a gas to escape. Boyle's law tells us that if we increase the volume, the pressure inside will decrease. Likewise, if we decrease the volume, the pressure inside will increase.
If a closed container is filled with a fluid, a pressure applied to the fluid will produce an equal pressure at each and every point on the inner surface.
FAQ Surface Area:
Most phenomena in breathing and respiration take place at one surface or another. As surface area increases, more gases can be exchanged or treated.