The heart, a secondary organ in the control of blood circulation

Abstract

Circulation of the blood is a fundamental physiological function traditionally ascribed to the pressure‐generating function of the heart. However, over the past century the ‘cardiocentric’ view has been challenged by August Krogh, Ernst Starling, Arthur Guyton and others, based on haemodynamic data obtained from isolated heart preparations and organ perfusion. Their research brought forth experimental evidence and phenomenological observations supporting the concept that cardiac output occurs primarily in response to the metabolic demands of the tissues. The basic tenets of Guyton's venous return model are presented and juxtaposed with their critiques. Developmental biology of the cardiovascular system shows that the blood circulates before the heart has achieved functional integrity and that its movement is intricately connected with the metabolic demands of the tissues. Long discovered, but as yet overlooked, negative interstitial pressure may play a role in assisting the flow returning to the heart. Based on these phenomena, an alternative circulation model has been proposed in which the heart functions like a hydraulic ram and maintains a dynamic equilibrium between the arterial (centrifugal) and venous (centripetal) forces which define the blood's circular movement. In this focused review we introduce some of the salient arguments in support of the proposed circulation model. Finally, we present evidence that exercising muscle blood flow is subject to local metabolic control which upholds optimal perfusion in the face of a substantive rise in muscle vascular conductance, thus lending further support to the permissive role of the heart in the overall control of blood circulation.

Heat‐related changes in the velocity and kinetic energy of flowing blood influence the human heart's output during hyperthermia

“…The classic cardiocentric postulate is that the heart is the primary organ generating the mechanical energy (pressure energy) to distribute systemic blood flow to organs and tissues (Rowell, 1993;Secomb, 2016). This view has been termed the pressure-propulsion model (Furst, 2020;Furst & González-Alonso, 2024), and is exemplified by the close temporal relationship between the blood pressure and flow waves in the aorta (Khir & Parker, 2005;Mynard et al, 2018;Parker & Jones, 1990) and the conduit arteries (Nichols et al, 2022). The observation that arterial, central venous and femoral venous pressures are maintained or only slightly altered (e.g.…”

“…However, no study to date has explored the associations between heat-related changes in peripheral blood velocity or kinetic energy and the heart's output in humans. Answering this question will not only shed light on the longstanding debate of what drives blood circulation (Folkow & Neil, 1971;Furst, 2020;Furst & González-Alonso, 2024;Guyton, 1967;Joyce & Wang, 2021;Krogh, 1912a,b;Patterson & Starling, 1914;Rowell, 1993), but will also help establish the effectiveness of passive lower-limb heating as a therapeutic intervention to improve cardiovascular health.…”

What is the point of cerebral blood flow?

“…Nevertheless, a number of physiologists have presented alternative non-cardiocentric conceptualizations of cardiac function (e.g. Furst & González-Alonso, 2024;Stöhr, 2022). Stöhr (2022) suggested that perhaps cardiac function serves a different, as yet unknown, purpose.…”