Renal physiology nephron, functions

This chapter is divided into three sections. The first section covers renal tubule transport mechanisms. The nephron is divided structurally and functionally into several segments (Figure 15-1, Table 15-1). Many diuretics exert their effects on specific membrane transport proteins in renal tubular epithelial cells. Other diuretics exert osmotic effects that prevent water reabsorption (mannitol), inhibit enzymes (acetazolamide), or interfere with hormone receptors in renal epithelial cells (aldosterone receptor blockers). The physiology of each segment is closely linked to the basic pharmacology of the drugs acting there, which is discussed in the second section. Finally, the clinical applications of diuretics are discussed in the third section. 

Most diuretics act upon a single anatomic segment of the nephron (Figure 15-1). Because these segments have distinctive transport functions, the first section of this chapter is devoted to a review of those features of renal tubule physiology that are relevant to diuretic action. The second section is devoted to the basic pharmacology of diuretics, and the third section discusses the clinical applications of these drugs. 

Renal function is an indication of the physiological state of the kidney glomerular filtration rate (GFR) describes the flow rate of Altered fluid through the kidney, while creatinine clearance rate (Ccr) is the volume of blood plasma that is cleared of creatinine per unit time, and is a useful measure for approximating the GFR. Most clinical tests use the plasma concentrations of the waste substances of creatinine and urea, as well as electrolytes, to determine renal function. The nephron is the functional unit of the kidney (Figure 10.1) it consists of two parts ... 

The GFR is considered to be the most reliable measure of the functional capacity of the kidneys and is often thought of as indicative of the number of functioning nephrons. As a physiological measurement, it has proved to be the most sensitive and specific marker of changes in overall renal function. Measurement of GFR is discussed in Chapter 24,... 

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