Figure 2: High power electron micrograph of acinar cells showing mitochondria (M) with lamellar cristae and junctional complexes (Jc). The electron-dense secretory granules (Sg) lie below the apical plasma membrane and fuse with the apical plasma membrane, releasing their content into the lumen. The luminal surface of acinar cells shows long and thick microvilli (Mv) projecting into the lumen (L). The lumen content homogeneous electron-dense and electron-opaque secretion (S). 20,000× magnification.