RT Book, Section A1 Baum, Michel A2 Kline, Mark W. SR Print(0) ID 1182912852 T1 Renal Tubular Disorders T2 Rudolph's Pediatrics, 23e YR 2018 FD 2018 PB McGraw-Hill Education PP New York, NY SN 9781259588594 LK accesspediatrics.mhmedical.com/content.aspx?aid=1182912852 RD 2024/03/29 AB There are approximately 1 million glomeruli in each kidney, which filter blood and generate an ultrafiltrate of plasma. With a glomerular filtration rate of 120 mL/min/1.73 m2, the kidneys of an adult generate approximately 170 L of an ultrafiltrate of plasma daily, which is delivered to the renal tubules. The renal tubules reabsorb organic solutes, salts, and water to maintain a constant extracellular fluid volume and composition. In addition, organic anions and cations, which are protein bound and not filtered by the glomerulus, are secreted by the proximal tubule. The final urine contains about one hundredth of the volume and sodium as that in the original glomerular filtrate, but contains waste products. There are 12 nephron segments, which have different transport properties to perform the task of modifying the glomerular ultrafiltrate so that we maintain a constant volume and composition of the extracellular fluid. Disorders of tubular function can be due to inherited defects in transporters, result from mutations in factors that regulate transport, or result from inherited or acquired disorders that cause tubular injury. Renal transport disorders can be mild, with little or no clinical consequences, or life-threatening depending on the transporters and nephron segments affected.