Figure 2.

Key components of the mathematical model. The oocyte is surrounded by the extracellular unconvected fluid (EUF), which in turn is surrounded by the bulk extracellular fluid (BECF). The BECF is an infinite reservoir for all solutes, where convection (not included in the present model) could occur but no reaction or diffusion. All solutes can diffuse between the BECF and EUF. The EUF is a thin layer of thickness d adjacent to the oocyte surface where no convection occurs, but reaction and diffusion do occur. The plasma membrane is permeable only to CO₂. In the intracellular fluid (ICF), both reaction and diffusion occur. In both the EUF and ICF the model accounts for the slow equilibration of the CO₂ hydration/dehydration reactions, competing equilibria among the ${\text{CO}}_2/{\text{HCO}}_3^{-}$ buffers and a multitude of ${\text{non}-\text{CO}}_{\text{2}}{/\text{HCO}}_3^{-}$ buffers (indicated as ${\text{HA}}_{\ell }/{\text{A}}_{\ell }^{-}$).