Quantitative analysis of the oxygen transfer in the human acinus.

The gas transport in the acinus is limited at rest by the finite oxygen diffusivity. Although the simplest steady-state model of diffusion permits understanding a number of observations, it fails to quantitatively fit the value of the absolute flux of oxygen at rest and exercise. In this paper, we show that the binding of oxygen to hemoglobin modifies these values only slightly. In contrast, the dynamics of breathing have a strong effect and allow recovery to known experimental values for oxygen transfer.