Figure 4.

Graph showing flow-limited exchange between plasma and surrounding regions. The response h_R(t) is a vascular reference curve identical to that of Figure 3. The outflow curves [h(t)s] for the permeant represent three cases with free entry and exchange with endothelial cells only (h_D1), with endothelial cells plus interstitial fluid (h_D2), and with all three extravascular regions (h_D3). h_R is the intravascular reference tracer. The mean transit time, t̄, for each case is the total volume of distribution divided by the flow F_s = 1.0 (ml/g)/min. The volumes were V_p = 0.05, ${\mathrm{V}}_{\text{ec}}^{\prime }=0.05$, ${\mathrm{V}}_{\text{isf}}^{\prime }=0.10$, and ${\mathrm{V}}_{\text{pc}}^{\prime }=0.2\text{ml}/\mathrm{g}$. (For definition of terms, refer to Figure 1.) V_tot is the total volume accessible to solute, ml/g.