Local Control of Microvascular Perfusion

Abstract

Physiology is a scientific discipline devoted to understanding the functions of the body. It addresses function at multiple levels, including molecular, cellular, organ, and system. An appreciation of the processes that occur at each level is necessary to understand function in health and the dysfunction associated with disease. Homeostasis and integration are fundamental principles of physiology that account for the relative constancy of organ processes and bodily function even in the face of substantial environmental changes. This constancy results from integrative, cooperative interactions of chemical and electrical signaling processes within and between cells, organs and systems. This eBook series on the broad field of physiology covers the major organ systems from an integrative perspective that addresses the molecular and cellular processes that contribute to homeostasis. Material on pathophysiology is also included throughout the eBooks. The state-of the-art treatises were produced by leading experts in the field of physiology. Each eBook includes stand-alone information and is intended to be of value to students, scientists, and clinicians in the biomedical sciences. Since physiological concepts are an ever-changing work-in-progress, each contributor will have the opportunity to make periodic updates of the covered material.Published titles (for future titles please see the website, AbStrACtLocal control of microvascular perfusion refers to the ability of individual tissues to maintain a relative constancy of hemodynamics in the face of changing perfusion pressure while meeting metabolic demands appropriately. The regulation of local blood flow, or autoregulation, and its underlying mechanisms have been a subject of considerable interest for over 100 years. Particular focus has been placed on the acute interaction of myogenic (pressure-induced) and metabolic (local production of vasodilator metabolites) parameters and how they interact with flow (shear stress)-dependent and conduction-based mechanisms to produce integrated local vascular network responses (for example, as seen during reactive and functional hyperemia). This monograph discusses each of these vasoregulatory phenomena while also considering evidence for their underlying cellular mechanisms. Further, an attempt is made to integrate the information into complex in vivo situations and consider their relevance to pathophysiological situations. vi

Application of Spectral Methods of Analysis for Description of Ultradian Biorhythms at the Levels of Physiological Systems, Cells and Molecules (Review)

“…This phenomenon, known as the "myogenic arteriole response", maintains microvascular perfusion at a constant level despite oscillations in blood pressure [171]. The expansion of the lumen of the vessels is called vasodilation, and the narrowing is called vasoconstriction [173].…”

“…The mechanisms of the regulation of the rate of local microhemodynamics include flowinduced vasodilation. It is an expansion of the lumen of blood vessels in response to shear stress and metabolic and neuronal control mechanisms [173]. Among the latter, signals from the sympathetic nervous system induce vasoconstriction, while parasympathetic neurons are able to induce vasodilation by releasing signaling molecules: calcitonin gene-related peptide (CGRP) and substance P [174].…”

The Terminologia Anatomica matters: examples from didactic, scientific, and clinical practice

“…For example, there is currently no precise definition of fascia as a unit [15,25,26]. Similarly, we lack an exact definition of an arteriole [8]. Moreover, numerous terms are stated as synonyms [13].…”