Nephrons function

NAPQI N-acetyl-p-benzoquinone imine. nephron functional unit of the kidney. 

The kidneys are a common site of chemical toxicity since the nephron functions to concentrate the toxicant and thus increase levels of exposure to the materials. This increased exposure can result from the concentration of the toxicant in the tubules. It also can occur by concentration within the cells of the nephrons when a chemical is capable of utilizing one of the active transport proteins and is shuttled from the lumen of the tubules into the renal cells. 

Micropuncture techniques have been applied to the direct investigation of the effect of diuretics on single nephron function. The observed changes in tubular fluid reabsorptive rates and electrolyte concentrations can be used to asses the mechanism of action. The... 

The determination of renal function in anesthetized animals provides specific information on the effects of chemicals on glomerular filtration rate and renal blood flow. In addition, the ability of the kidney to reabsorb or secrete electrolytes may be determined by fractional clearance of Na+, K+, HCO3, Cl, and so on. Fractional clearance involves comparison of electrolyte clearance to the clearance of a substance such as inulin, which is removed from plasma by glomerular filtration. Thus, fractional clearance takes glomerular filtration rate into account, allowing comparisons of electrolyte transport between treated and control animals even if renal hemodynamics have changed. Nephron function may be assessed by free water clearance, representing the ability of the kidney to remove almost all Na+ from urine. 

Figure 2.16. Nephron function, a Filtration occurs in the glomerulus. The filtrate is fuimeled into the tubule, b Schemat-ie of the blood vessel wall stiueture in the glomeralus. Both the endothelium within and the podocytes outside the arterioles have sUts and fenestrations that are a few nanometers wide. As in the eapillaries elsewhere in the body, the basal membrane functions as the sieve, e In the tubule and the colleeting duct, the filtrate is extensively post-proeessed water, substrates and ions are reabsorbed but also aetively secreted and exchanged. Tubular processing is under hormonal control.

Batlle DC, Gaviria M, Grupp M. Distal nephron function In patients receiving chronic lithium therapy. Kidney Int 1982 21 477-485. 

Sebastian A, Hulter HN, Kurtz I, Maher T, Schambelan M. Disorders of distal nephron function. Am J Med 1982 72 289-307. 

Uraemic coma is a condition produced when excessive by-products of protein metabolism (e.g. urea) are accumulated in the blood. It occurs when the kidney nephron function is inadequate at coping with excretion of urea and related compounds. It has been proposed by Sen [1839-1841 ] that the underlying cause for uraemic coma is the generation of... 

In contrast to hemodialysis, hemofiltration relies on convective transport and thus is more analogous to nephron function. Hydrostatic pressure is used to form about 80 to 100... 

Nephron Functional unit of the kidney, consisting of a glomerulus. Bowman s capsule, renal tubule. 

Polish children (N = 112 total exposed N = 62 controls N = 50) Exposed PbB mean = 13.3 Lg/dl control mean = 3.9 Pg/dl 29 urinary or serum markers for nephron function Increased 32-microglobulin and Clara cell protein with increased PbB Fels et al. (1998)... 

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