The cortical radiate arteries continue to divide eventually forming afferent arterioles that split into a tiny bundle of capillaries called the glomerulus.

小叶间动脉继续分支，最后形成入球小动脉；后者再分成若干小支形成一团微小的毛细血管球，即肾小球。

In fact, the mesangium is continuous with the smooth muscles of the afferent and efferent arterioles, and fills in the space between the loops of blood vessels, hence the name.

事实上，系膜是由入球、出球小动脉的平滑肌细胞延续而来，填满了毛细血管袢的空隙，因此得名Mes-angium。

So, in the case of hypovolemia and hypotension, the macula densa cells sense the low sodium and chloride levels and send a signal over to the juxtaglomerular cells which are located in the wall of the afferent arteriole.

因此，当血容量减少、低血压时，致密斑感受到钠、氯含量降低，传递信号给位于入球小动脉血管壁上的球旁细胞。