Anderson B G, Loewen R D
Am J Anat. 1975 May;143(1):93-114. doi: 10.1002/aja.1001430105.
The nephron of the euryhaline freshwater salmonids is composed of the renal corpuscle and the renal tubules. Throughout much of the renal corpuscle, only the lamina densa separates the fenestrated processes of the endothelial cells from the foot processes of the visceral epithelium. The renal tubule consists of five distinct segments. The neck segment is short and intermittently ciliated; it lacks the mucous cells which appear in the neck segment of some teleosts. The proximal segment bears a dense bruch border and is both structurally and functionally divisible into a first and a second segment. The first portion is typified by the presence of short apical tubules, variously sized apical vacuoles, and numerous lysosomes. The second proximal segment is distinguished by the abundance and distribution of mitochondria throughout the cytoplasm. Infoldings of the basilar plasmalemma are especially prominent in this region. A cilated intermidate segment intervenes briefly between the proximal and distal portions of the tubule. The distal segment consists of cuboidal cells which bear scattered, short microvilli, small vesicles and multivesicular bodies. Renal tissue from several species of trout was examined in order to establish the basis for a common pattern of histological and ultrastructural characteristics within the family Salmonidae. In all species examined, renal structure was very similar and could readily be compared with that previously described in other freshwater and marine species.
广盐性淡水鲑科鱼类的肾单位由肾小体和肾小管组成。在肾小体的大部分区域，只有基膜将内皮细胞的窗孔状突起与脏层上皮的足突分隔开来。肾小管由五个不同的节段组成。颈部节段很短，有间断的纤毛；它没有一些硬骨鱼类颈部节段中出现的黏液细胞。近端节段有密集的刷状缘，在结构和功能上均可分为第一和第二节段。第一部分的特点是存在短的顶端小管、大小不一的顶端空泡和大量溶酶体。第二个近端节段的特征是线粒体在整个细胞质中的丰富程度和分布情况。基底质膜的内褶在该区域尤为突出。一个有纤毛的中间节段在肾小管的近端和远端部分之间短暂介入。远端节段由立方体细胞组成，这些细胞有分散的短微绒毛、小泡和多泡体。对几种鳟鱼的肾组织进行了检查，以便为鲑科鱼类中常见的组织学和超微结构特征模式奠定基础。在所检查的所有物种中，肾脏结构非常相似，并且很容易与先前在其他淡水和海洋物种中描述的结构进行比较。
