Physiological model of the full baroreflex heart control system based on experimental measurements

Description

This is a phenomenological ODE model of baroreflex open-loop 
control of heart rate.  An aortic blood pressure signal 
(the driving signal for the model) is transduced by afferent 
baroreceptor nerve fibers in the wall of the aortic arch into 
a neural (firing rate) signal. This transduction process is 
governed by mechanical strain in the wall of the aorta. This 
neural signal is then relayed and further processed by the 
central and peripheral nervous systems into parallel 
sympathetic and parasympathetic tone signals. Sympathetic and 
parasympathetic tones drive release of norepinephrine and 
acetylcholine, respectively, into the neuromuscular junction 
of the sinoatrial node of the heart, thereby modulating the 
pacemaker activity at the sinoatrial node. The sinoatrial 
node is the ultimate effector of heart rate, which is the model 
output.

Parameters used to reproduce the figures in the paper were taken 
from Table 5 of the paper. All pressure data was taken over a 
period of 120 seconds at a rate of 100 samples per second. Heart 
rate data was derived from the pressure data using a high-pass 
filter while detecting the upstroke zero-crossings.

LIMITATIONS
The model cannot fully account for the fast dynamics of the 
parasympathetic nervous system. Additionally, time delays in the 
peripheral nervous system are assumed to be negligible and have 
been omitted. 

ERRATA 
The caption for Figure 8 in the paper erroneously states: 
"Data shown in A and B are from the SS and SS.13BN strains, 
respectively." and should read:
"Data shown in A and B are from the SS.13BN and SS strains, 
respectively." 

The strain attributions were transposed; 8A is from SS.13BN 
along with its derived graphs, C and E, while 8B is from Dahl SS 
along with D and F. The plots contained in this project are labeled 
correctly.

This figure is similar to Figure 8 in the referenced publication.

Equations

None.

The equations for this model may be viewed by running the JSim model applet and clicking on the Source tab at the bottom left of JSim's Run Time graphical user interface. The equations are written in JSim's Mathematical Modeling Language (MML). See the Introduction to MML and the MML Reference Manual. Additional documentation for MML can be found by using the search option at the Physiome home page.