In HA12, at medium magnification, note the presence of a small interlobular duct (arrow) surrounded by CT and blood vessels (a, v) and lymphatics (l) in the interlobular region. In the middle of this image, there is a secretory acinus with darkly stained vesicles in the apical half of the cells. This acinus has a doughnut-shaped intercalated duct (arrowhead) at its center. On the left side of the image there are other secretory acini and striated ducts (s).