Transport of water and hydrophilic solutes across microvascular walls (capillaries and postcapillary venules) is an essential mechanism for delivery of nutrients to tissues. The ease of water movement across microvessel walls is described by the coefficient hydraulic conductivity (Lp). Lp reflects net volume flux (cm3 sec-1) per unit surface area (cm2) per unit pressure (cmH2O). Lp was assumed previously to be a fixed property of microvessels; however, it is now evident that Lp may be regulated actively under both physiologic and pathologic conditions. In this chapter, we review current aspects of regulation of Lp, common methods for assessing this coefficient in vivo, and implications of alterations in L We will limit our scope to data derived from in vivo models; techniques for in vitro assessment of Lp of cultured endothelial cell monolayers are exemplified by the work of Tarbell and colleagues .
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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.