Description of Guyton capillary dynamics module

Description of Guyton capillary dynamics module

CellML 1.1 Version

This is a CellML 1.1 version of the Capillary Dynamics Module of the Guyton Circulation model. To run, click on "Solve using OpenCell" and all dependent files and components will be imported. To run offline, please download all files from the workspace into the same directory and open "cap_dynamics_parent.cellml" in OpenCell.

Model Status

This CellML model has been validated. Due to the differences between procedural code (in this case C-code) and declarative languages (CellML), some aspects of the original model were not able to be encapsulated by the CellML model (such as the damping of variables). This may effect the transient behaviour of the model, however the steady-state behaviour would remain the same. The equations in this file and the steady-state output from the model conform to the results from the MODSIM program.

Model Structure

Arthur Guyton (1919-2003) was an American physiologist who became famous for his 1950s experiments in which he studied the physiology of cardiac output and its relationship with the peripheral circulation. The results of these experiments challenged the conventional wisdom that it was the heart itself that controlled cardiac output. Instead Guyton demonstrated that it was the need of the body tissues for oxygen which was the real regulator of cardiac output. The "Guyton Curves" describe the relationship between right atrial pressures and cardiac output, and they form a foundation for understanding the physiology of circulation.

The Guyton model of fluid, electrolyte, and circulatory regulation is an extensive mathematical model of human circulatory physiology, capable of simulating a variety of experimental conditions, and contains a number of linked subsystems relating to circulation and its neuroendocrine control.

This is a CellML translation of the Guyton model of the regulation of the circulatory system. The complete model consists of separate modules each of which characterise a separate physiological subsystems. The Circulation Dynamics is the primary system, to which other modules/blocks are connected. The other modules characterise the dynamics of the kidney, electrolytes and cell water, thirst and drinking, hormone regulation, autonomic regulation, cardiovascular system etc, and these feedback on the central circulation model. The CellML code in these modules is based on the C code from the programme C-MODSIM created by Dr Jean-Pierre Montani.

This particular CellML model describes the the movement of fluid and protein through the capillary membrane. It also calculates the volumes of fluid in the free fluid space of the interstitium and in the gel fluid space. It calculates the pressures in both of these fluids as well as the so-called solid tissue pressure caused by the compression of solid elements against other portions of the interstitium. In addition, the quantities of proteins and their concentrations in both the free fluid and the gel fluid are calculated. And, finally, the flow of both fluid and proteins in the lymph system are computed, as well as the overall body protein balance.

A systems analysis diagram for the full Guyton model describing circulation regulation.
A schematic diagram of the components and processes described in the current CellML model.

There are several publications referring to the Guyton model. One of these papers is cited below:

Circulation: Overall Regulation, A.C. Guyton, T.G. Coleman, and H.J. Granger, 1972, Annual Review of Physiology , 34, 13-44. PubMed ID: 4334846