It is rapidly becoming recognized that the formation of reactive oxygen species (ROS), reactive nitric oxide (NO)-derived species (RNS), and their interaction with cellular regulatory systems are fundamental components of signaling systems that contribute to the control of physiological and pathophysiological aspects of microvascular function in processes such as the activation of certain receptors and cellular systems which sense changes in oxygen tension, flow, and pressure. Oxidase enzymes are the primary source of generation of ROS as a result of their ability to transfer electrons to molecular oxygen, forming species including superoxide anion (O2-) and hydrogen peroxide (H2O2), as a result of the oxygen accepting one or two electrons, respectively. Although the levels of these ROS are kept extremely low by metabolizing enzymes including superoxide dismutases, peroxidases, and catalase, and antioxidants that also control the actions of RNS, each individual ROS and RNS has concentration-dependent mechanisms through which it interacts with intracellular and intercellular signaling systems that control processes within each cell type in the microcirculation (e.g., endothelium and vascular smooth muscle).
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This ebook provides an introductory explanation of the workings of the human body, with an effort to draw connections between the body systems and explain their interdependencies. A framework for the book is homeostasis and how the body maintains balance within each system. This is intended as a first introduction to physiology for a college-level course.