Solubilities of respiratory gasses in water, saline and plasma decrease with rising temperatures and solute concentrations. Henry's Law, C = α.P, states: the equilibrium concentration of a dissolved gas is solubility times partial pressure. Solubilities in the water of a solution depend on temperature, and the content of other solutes,. Blood temperatures may differ more than 20°C between skin and heart, and an erythrocyte will undergo that range as blood circulates. The concentrations of O2 and CO2 are the driving force for diffusion, exchanges and for reactions We provide an equation for O2 and CO2, α, that allows for continuous changes in temperature, T, and solution density, ρ, in dynamically changing states: Eqyation This two-exponential expression with a density scalar γ, and a density exponent β, accounts for solubility changes due to density changes of an aqueous solution. It fits experimental data on solubilities in water, saline and plasma over temperatures from 20 to 40°C, and for plasma densities, ρsol, up to 1.020 g/ml with about 0.3% error. The amounts of additional bound O2 (to Hb) and CO2 (bicarbonate and carbamino) depend on the concentrations in the local water space and the reaction parameters. During exercise, solubility changes are large; both ρsol and T change rapidly with spatial position and with time. In exercise hemoconcentration plasma ρsol exceeds 1.02. while T may range over 20°C. The six paramenters for O2 and the six for CO2 are constants, so solubilities are calculable continuously as T and ρsol change.
- respiratory gasses
- carbon dioxide
- plasma density
- Copyright © 2017, Journal of Applied Physiology