The macula densa (HA5 m) forms at the junction of the ascending thick limb and distal convoluted tubule where the DCT contacts its renal corpuscle. Macula densa means “dense spot” and this name makes sense due to its tightly packed nuclei. Although it cannot be easily seen here, they have reverse polarity, so their nuclei are found apically, close to the DCT. They secrete from their basal surfaces to send paracrine signals to the JG cells to (JG) stimulate renin secretion. In this section you can see both the vascular (v) and the urinary (u) poles (HA5) of the renal corpuscle. This image shows good examples of an afferent arteriole and a portion of the peritubular vascular network (arrows) that surrounds PCTs.