Fig. 6.

Light microscopy (A, C, F, and G) and TEM images (B, D, and E) of the thick epithelium of the oral ridges, showing two glandular cell types (A–F) columnar cells (cc), and (F and G) cell type 1 (ct1). (A and B) The columnar cells are slender and contain small, round to polygonal granules with an electron-dense core. Scale bar in (A) = 10 μm, in (B) = 2 μm. (C) For secretion, small vesicles filled with several granules are pinched off. Scale bar = 10 μm. (D) When the granules are synthesized in the basal area of the cells, they already contain the electron-dense core. Scale bar = 2 μm. (E) Columnar cell granules in high magnification. Scale bar = 500 nm. (F) Cell type 1 (ct1) and the columnar cells (cc) show a positive reaction to PAS staining (neutral sugars), as confirmed by Fig. 7. Scale bar = 10 μm. (G) Semithin section of cell type 1 (ct1) and the columnar cells (cc). Scale bar = 10 μm.