Oxygen Transport in the Microcirculation and Its Regulation

• Published in: Microcirculation (New York, N.Y. 1994) Vol. 20; no. 2; pp. 117 - 137
• Main Author: Pittman, Roland N.
• Format: Journal Article
• Language: English
• Published: United States Blackwell Publishing Ltd 01-02-2013; Wiley Subscription Services, Inc
• Subjects: Animals; Aquatic plants; arteriole; capillary; Circulatory system; Erythrocytes - metabolism; Extracellular Fluid - metabolism; hemoglobin; Humans; intravital video microscopy; Microcirculation - physiology; microspectrophotometry; Models, Biological; Oximetry - methods; Oxygen; Oxygen - metabolism; oxygen consumption; Oxygen Consumption - physiology; oxygen saturation; oxygen tension; oxygen transport; phosphorescence quenching; red blood cell
• ISSN: 1073-9688; 1549-8719
• DOI: 10.1111/micc.12017

Objective
Cells require energy to carry out their functions and they typically use oxidative phosphorylation to generate the needed ATP. Thus, cells have a continuous need for oxygen, which they receive by diffusion from the blood through the interstitial fluid. The circulatory system pumps oxygen‐rich blood through a network of increasingly minute vessels, the microcirculation. The structure of the microcirculation is such that all cells have at least one nearby capillary for diffusive exchange of oxygen and red blood cells release the oxygen bound to hemoglobin as they traverse capillaries.
Methods
This review focuses first on the historical development of techniques to measure oxygen at various sites in the microcirculation, including the blood, interstitium, and cells.
Results
Next, approaches are described as to how these techniques have been employed to make discoveries about different aspects of oxygen transport. Finally, ways in which oxygen might participate in the regulation of blood flow toward matching oxygen supply to oxygen demand is discussed.
Conclusions
Overall, the transport of oxygen to the cells of the body is one of the most critical functions of the cardiovascular system and it is in the microcirculation where the final local determinants of oxygen supply, oxygen demand, and their regulation are decided.