At higher magnification (HA38) the acini are strikingly polarized cells. The apex is filled with acidophilic secretory granules, while the base is filled with clumps of basophilic material (RER). If the plane of section is just right, you will see the nucleus of a centroacinar cell (arrowhead) in the center of the acinus. The centroacinar cell and its acinus resemble a flower. The centroacinar cell marks the beginning of the intercalated duct.