Fig. 1.

The organs and pathways associated with the baroreflex control system are shown on the left. The system’s response to a drop in blood pressure includes a decrease in the aortic baoreceptor firing rate, encoding the detected change in arterial wall strain. This signal propagates along afferent baroreceptor fibers to the NTS, which integrates this information into the sympathetic and parasympathetic nervous systems. These in turn increase heart rate, cardiac contractility, and vascular resistance, and decrease vascular compliance. The right panel shows the modeling framework as a block diagram representing the biophysical basis of baroreceptor firing in response to an applied blood pressure stimulus. Abbreviations: BR (baroreceptor nerve endign), NTS (Nucleus Solitary Tract), SA (Sino Atrial node), p (arterial blood pressure), ε_w (arterial wall strain), ε_ne (nerve ending strain), and f (baroreceptor firing rate).