Stephenson J L
Fed Proc. 1983 May 15;42(8):2386-91.
Five theoretical principles that follow from qualitative consideration of renal architecture and tubular permeabilities are proposed to explain the concentration of urine in the mammalian kidney. These are: 1) The medullary loop of the doubly folded S-shaped configuration of the nephron permits solute supplied by ascending Henle's limb (AHL) to extract water from descending Henle's limb (DHL) and collecting duct (CD). 2) The cortical loop allows the diluted AHL fluid to return to isotonicity with cortical plasma before returning to the medulla. 3) The folded vasa recta and surrounding interstitium (the central core) provide an expansion chamber for the performance of osmotic work and a mixing chamber for salt and urea. This mixing induces passive salt transport out of AHL. 4) Overall, the system acts as a solute cycling multiplier from the AHL to vascular core and the osmotically equilibrated DHL and CD. 5) The short-looped nephrons provide urea to drive salt transport out of AHL of long nephrons in the inner medulla.
从肾脏结构和肾小管通透性的定性考量得出的五条理论原则被提出来用以解释哺乳动物肾脏中尿液的浓缩。它们是：1）肾单位呈双折S形结构的髓袢使得由亨氏袢升支（AHL）供应的溶质能够从亨氏袢降支（DHL）和集合管（CD）中提取水分。2）皮质袢允许稀释的AHL液体在返回髓质之前恢复到与皮质血浆等渗。3）折叠的直小血管及其周围的间质（中央核心）为渗透作用提供了一个扩张腔室，为盐和尿素提供了一个混合腔室。这种混合促使盐从AHL被动转运出去。4）总体而言，该系统作为一个溶质循环倍增器，从AHL到血管核心以及渗透平衡的DHL和CD发挥作用。5）短袢肾单位提供尿素以驱动内髓质中长肾单位的AHL中的盐转运出去。
