Comparative aspects of the urinary concentrating process.
Comparative aspects of the urinary concentrating process.
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尿液浓缩过程的比较方面。
DOI：
10.1159/000173058
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Braun,EJ
中科院分区：
文献类型：
--
作者：
Braun,EJ
只有鸟类和哺乳动物可以产生比血浆渗透压更高的尿液。在这两个脊椎动物组中，这是通过逆流倍增系统的操作来实现的，尽管两组之间的系统细节可能有所不同。在大多数哺乳动物中，亨利氏袢有一个长度不等的细的上升肢。在鸟类中，Henle袢没有薄的上升部分，因为在发夹弯之前小管上皮总是增厚。在哺乳动物中，尿素和氯化钠均有助于髓质间质渗透梯度，尽管每种渗透剂的确切作用可能随时间和种属而异。在鸟类中，间质渗透梯度几乎完全由氯化钠组成。鸟类肾髓质（髓锥）的发育与哺乳动物的外髓质非常相似。
Only birds and mammals can produce urines that have higher osmolalities than their plasma. In both of these vertebrate groups this is accomplished through the operation of a countercurrent multiplier system although the details of the system may differ somewhat between the two groups. In most mammals the loop of Henle has a thin ascending limb of variable length. In birds, the loop of Henle does not have a thin ascending portion as the tubule epithelium always thickens before the hairpin turn. In mammals, both urea and sodium chloride contribute to the medullary interstitial osmotic gradient although the exact contribution of each osmolyte can vary in time and from species to species. In birds the interstitial osmotic gradient is made up almost entirely of sodium chloride. The development of the avian renal medulla (medullary cone) is very similar to the outer medulla of mammals.