Table 4. Equilibrium values.

Variable	Unit	Description	Reference
ωi = 1400	μm	cell volume	Matsui et al. (2000)
Hi = 28.7	μm	cell height	Matsui et al. 2000
[Na+]p = 103	mM	PCL Na+ concentration	Jayaraman, Song et al. (2001)
[K+]p = 20.8	mM	PCL K+ concentration	Namkung et al. (2009)
[Cl−]p = 92	mM	PCL Cl− concentration	Jayaraman, Song et al. (2001)
[H+]p = 1.55×10−4	mM	PCL H+ concentration	Jayaraman, Joo et al. (2001)
${[{\text{HCO}}_3^{-}]}_p=31.8$	mM	${\text{PCL HCO}}_3^{-}\text{concentration}$	determined from modelb
[CO2]p = 11.6	mM	PCL CO2 concentration	determined from Eq. (25)
[Na+]i = 22	mM	intracellular Na+ concentration	Willumsen & Boucher (1991)
[K+]i = 117	mM	intracellular K+ concentration	Treharne et al. (2006)
[Cl−]i = 42.7	mM	intracellular Cl− concentration	Willumsen et al. (1989)
[H+]i = 1.23×10−4	mM	intracellular H+ concentration	Stewart et al. (2001)
${[{\text{HCO}}_3^{-}]}_i=12$	mM	${\text{intracellular HCO}}_3^{-}\text{concentration}$	Smith & Crampin (2006)
[CO2]i = 3.5	mM	intracellular CO2 concentration	determined from Eq. (26)
Va = -29	mV	apical membrane potential	Cotten et al. (1987)
Vb = -36.2	mV	basolateral membrane potential	Willumsen et al. (1989)
U0 = 1.92	μm/s	submucosal gland secretory flux	determined from model

^bThe equilibrium PCL ${\text{HCO}}_3^{-}$ concentration was found using the electroneutrality condition:

$$\begin{array}{c}{[{\text{HCO}}_3^{-}]}_p={[{\text{Na}}^{+}]}_p+{[{\mathrm{K}}^{+}]}_p-{[{\text{Cl}}^{-}]}_p-{[{\mathrm{H}}^{+}]}_p,\\ =31.8\text{mM}.\end{array}$$