Gambarian S P, Zemanova Z
Arkh Anat Gistol Embriol. 1991 Jan;100(1):62-8.
Microanatomy of nephrons during ontogenesis has been studied in domestic hens. In the bird kidneys, as well as in mammalian kidneys, three populations of nephrons can be detected: juxtamedullary, or deep nephrons, superficial and situating between them intracortical nephrons. In formation of the bird renal medulla only loops of the juxtamedullary nephrons participate. During ontogenesis in the kidneys of birds, like in mammalians, juxtamedullary nephrons are the first to be formed; they can be obtained from kidneys of 14-day-old chicken embryos, however, a complete formation of the nephron structure is terminated after hatching. During development the length of the juxtamedullary nephrons increases nearly by one order, while the length of the superficial and intracortical nephrons increases no more than twice. The diameter of the glomeruli in the juxtamedullary nephrons during development increases nearly twice, in the superficial and intracortical nephrons only a slight increase is noted. A relative length of the proximal canaliculus of the intracortical and superficial nephrons gradually increases during ontogenesis and practically does not change in the juxtamedullary nephrons, in them the nephron loop becomes longer. The developmental pattern in various parts of the superficial, intracortical and juxtamedullary nephrons in general features is similar in mammalians and birds.
已对家鸡肾单位的个体发育过程中的微观解剖结构进行了研究。在鸟类肾脏中，与哺乳动物肾脏一样，可以检测到三种肾单位群体：近髓肾单位，即深层肾单位、浅表肾单位以及位于它们之间的皮质内肾单位。鸟类肾髓质的形成仅涉及近髓肾单位的袢。在鸟类肾脏的个体发育过程中，与哺乳动物一样，近髓肾单位是最先形成的；在14日龄鸡胚胎的肾脏中就可以找到它们，然而，肾单位结构的完全形成在孵化后才完成。在发育过程中，近髓肾单位的长度增加近一个数量级，而浅表肾单位和皮质内肾单位的长度增加不超过两倍。发育过程中，近髓肾单位中肾小球的直径增加近两倍，浅表肾单位和皮质内肾单位中仅略有增加。皮质内肾单位和浅表肾单位近端小管的相对长度在个体发育过程中逐渐增加，而近髓肾单位中实际上没有变化，其中肾单位袢变长。浅表肾单位、皮质内肾单位和近髓肾单位各部分的发育模式在总体特征上在哺乳动物和鸟类中相似。
