Model is underconstrained.
The following variables couldn't be defined:
 * c in component calcium_concentration
 * dc_dx2 in component calcium_concentration
 * dc_dy2 in component calcium_concentration
 * j_flux in component calcium_flux
 * j_pump in component calcium_pump
 * h in component calcium_flux
 * p in component calcium_flux
 * d/dt h in component calcium_flux
 * d/dt mu_p in component calcium_flux