vascular smooth muscle fferent arteriole efferent macula densa arteriole extraglomerular Juxta- mesangial cell glomerularcells capillary Bowman’s capsule podocyte 球旁器示图efferent arteriole efferent arteriole Juxta￾glomerular cells vascular smooth muscle macula densa extraglomerular mesangial cell capillary podocyte Bowman’s capsule 球旁器示意图