Respiration Laws

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The respiratory system seems to have many Laws and Effects and rules.  Here they are, all in one place:

bulletBoyles Law (p. 712):
bulletP1V1 = P2V2
bulletThis means that (if temperature is constant), if you have an enclosed space and the volume changes, the pressure does, too, but in a manner according to the original state.  So if the thoracic cavity has a certain volume and pressure, when you change the volume (for example, increase it for inspiration), the pressure will change as well (in this example, decrease) so that the V * P is constant.
bulletDalton's Law (p. 718):
bulletThis law simply says that if you add up all the partial pressures of the components of a gas, they will sum to the total pressure of the gas as a whole.  It also defines partial pressure as a component of the total pressure.
bulletHenry's Law (p. 719):
bulletThis law says that each component of a gas will diffuse into a liquid at a rate proportional to its partial pressure.  So the higher the pressure, the more of that gas that will enter the liquid.
bulletBohr effect (p. 725):
bulletThis says that oxygen unloading happens more readily (where it is needed) when CO2 and hydrogen ion concentration is higher.  This does relate to the fact that Hb carries O2 better when it doesn't also have to carry CO2 or H+, but that specific detail is part of the Haldane effect.
bulletHaldane effect (p. 726):
bulletThis relates to the fact that Hb carries CO2 or H+ better when it isn't also carrying O2.  It also says the opposite (that Hb carries O2 better when it doesn't also have to carry CO2 or H+).
bulletlung compliance (p. 715):
bulletThe compliance, or stretchiness, of lung tissue relates to how its total volume changes in relationship to the pressure applied to change its volume.  This should make sense because if a lot of pressure is needed, the lung musn't be very stretchy.  So, C = ΔV / ΔP , where the P is actually the transpulmonary pressure, measured as intra-alveolar pressure - intrapleural pressure


2011 STCC Foundation Press
written by Dawn A. Tamarkin, Ph.D.