A 2D model of axial symmetry for proximal tubule of an average human nephron: Indicative results of diffusion, convection and absorption processes

JORDÁN F. INSFRÁN; SEBASTIÁN UBAL; JOSÉ DI PAOLO

San Nicolás de los Arroyos

Congreso; XX Congreso Argentino de Bioingeniería / IX Jornadas de Ingeniería Clínica; 2015

Sociadad Argentina de Bioingeniería / UTN Facultad Regional San Nincolás

A simplified model of a proximal convoluted tubule of an average human nephron is presented. The model considers the 2D axisymmetric flow of the luminal solution exchanging matter with the tubule walls and the peritubular fluid by means of 0D models for the epithelial cells. The tubule radius is considered to vary along the conduit due to the trans-epithelial pressure difference. The fate of more than ten typical solutes is tracked down by the model. The Navier-Stokes and Reaction-Diffusion-Advection equations (considering the electroneutrality principle) are solved in the lumen, giving a detailed picture of the velocity, pressure and concentration fields, along with trans-membrane fluxes and tubule deformation, via coupling with the 0D model for the tubule wall. The calculations are carried out numerically by means of the finite element method. The results obtained show good agreement with those published by other authors using models that ignore the diffusive transport and disregard a detailed calculation of velocity, pressure and concentrations. This work should be seen as a first approach towards the development of a more comprehensive model of the filtration process taking place in the kidneys, which ultimately helps in devising a device that can mimic/complement the renal function.