Fluid and Osmotic Pressure Balance and Volume Stabilization in Cells
  • Peter M. Pinsky*
Department of Mechanical Engineering, Stanford University, Stanford, 94305, CA, USA
* Corresponding Author: Peter M. Pinsky. Email: pinsky@stanford.edu
(This article belongs to this Special Issue:Advances in Computational Mechanics and Optimization
To celebrate the 95th birthday of Professor Karl Stark Pister
)
Received 02 June 2021; Accepted 26 July 2021 ; Published online 07 September 2021
Abstract
A fundamental problem for cells with their fragile membranes is the control of their volume. The primordial solution to this problem is the active transport of ions across the cell membrane to modulate the intracellular osmotic pressure. In this work, a theoretical model of the cellular pump-leak mechanism is proposed within the general framework of linear nonequilibrium thermodynamics. The model is expressed with phenomenological equations that describe passive and active ionic transport across cell membranes, supplemented by an equation for the membrane potential that accounts for the electrogenicity of the ionic pumps. For active ionic transport, the model predicts that the intracellular fluid pressure will be balanced by the osmotic pressure and a new pressure component that arises from the active ionic fluxes. A model for the pump-leak mechanism in an idealized human cell is introduced to demonstrate the applicability of the proposed theory.
Keywords
Pump-leak mechanism; cell volume regulation; active ion transport; ion pump; membrane transport; cell mechanics; modified Kedem-Katchalsky equations; nonequilibrium thermodynamics; phenomenological equations