The heart, a secondary organ in the control of blood circulation, 2023, Branko Furst et al

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.

Abstract

• What is the topic of this review?
  
  The question whether the heart or the peripheral circulation is the main determinant of systemic blood flow is the subject of a longstanding debate: in this review, the main theories explaining blood circulation are discussed.
  
  
• What advances does it highlight?
  
  The limitations of the prevailing ‘cardiocentric’ view of blood circulation are identified and an alternative view is put forward whereby the periphery plays a key role in the control of the magnitude of blood flow to the heart and thus the coupling of peripheral and central circulations.
  

https://physoc.onlinelibrary.wiley.com/doi/10.1113/EP091387

 

I accept that the heart isn't the be-all-end-all of circulation. Early organisms probably used vascular contractions to move blood around, and evolution resulted in a single pump as optimal.

I am confused about applying the terms "centrifugal and centripetal forces" to explain blood flow. I was imagining some kook babbling about "holy circles of life" or some such thing. Circulation occurs because of a pressure difference and directional differential resistance to flow. For creatures without a discrete heart, there might be osmotic pressure difference, and a directional difference in resistance to flow (valves, texture, etc) to make the fluid circulate one-way.

I just skimmed the paper, but I still have the feeling that "kooky" applies.

 

I agree, this is a straw man paper. There never was such a thing as a cardio centric model. The subtleties of the mechanism have been understood for a very long time. From the abstract it looks as if many of the subtleties are not understood by the authors. I am surprised to see the Physiological Society publishing this but it probably bears little relation to the Society I knew in the 1980s.

Circulation will occur without an internal pump in a valved system under intermittent compression, but we all knew that. Negative interstitial pressure has not been ignored. It has been studied in detail. But it will not explain venous return. I don't think they have much of a clue.