arterymost

Arterymost is a term in vascular biology describing a functional unit within the arterial side of the microcirculation that acts as a regulatory node for regional blood flow. It is a conceptual construct rather than a single anatomical structure, used to explain how upstream arteries influence tissue perfusion.

The term emerged in the late 20th and early 21st centuries in discussions of microvascular regulation. It denotes the integrated activity of proximal arterial smooth muscle, perivascular signaling, and local endothelial responses that determine downstream vasodilation or vasoconstriction.

Anatomically, arterymost is imagined as a proximal arteriole with smooth muscle, adjacent capillary networks with pericytes, and signaling microdomains that coordinate responses to metabolic cues (such as oxygen tension and adenosine) as well as neural input and shear stress. Functionally, it modulates flow and vasomotion to balance tissue demand with systemic supply.

Evidence for a discrete arterymost unit is debated. Some studies describe coordinated arteriolar segments acting as regulatory hubs, while others attribute control to distributed network properties. The concept is most common in discussions of cerebral and retinal microcirculation, where precise flow control is essential and small changes can have large tissue effects.

Related topics include microcirculation, arterioles, pericytes, autoregulation, and vasomotion.