FOR 667: Epithelial Mechanisms in Renal Volume Regulation

肾脏每天过滤1500升血液，并产生180升初级超滤液。超滤液由肾小管形成，直到最终形成1.5升的尿液。肾小管上皮细胞的特殊活动有助于完成肾脏的这一主要任务。在小管中，过滤后的离子和水被重新吸收。此外，许多化合物根据瞬间的需要被运输进和运出，通过循环恢复，或排入尿液。体内的钠和水平衡受到肾脏机制的重要调节，这种机制有助于将血浆渗透压保持在严格的限制范围内，无论饮食中盐和水的摄取量有多大的差异。钠平衡的控制与血压的调节相辅相成。

The kidneys filter a daily input of 1500 liters of blood and produce 180 liters of primary ultrafiltrate. The ultrafiltrate becomes elaborated by the renal tubule until the final formation of 1.5 liters of urine. Specific activities of the tubular epithelium help to perform this major task of the kidney. In the tubule, filtered ions and water are being reabsorbed. In addition, many compounds are transported in- and outwards according to the momentary requirements to be recovered by the circulation, or excreted into the urine. Body sodium and water balance are importantly regulated by renal mechanisms which help to keep plasma osmolality within tight limits irrespective of the wide variations in dietary salt and water uptake. The control of sodium balance and the adjustment of blood pressure depend on each other.