Slide 98 - Trachea. The lining epithelium is the same type as in slide 96 but better preserved. (The "cracked" appearance in the lumen is due to the methacrylate embedding medium.) Notice the great numbers of goblet cells. Notice, too, that the nuclei of the tall columnar cell lie midway up the height of the cells and packed between the goblet cells, while the nuclei of basal and intermediate cells lie at the base. Of particular interest is the unusually thick and well preserved "basement membrane" which separates the epithelium from the underlying connective tissue as seen here, it is pink, homogeneous,and rather refractile in character To be visualized as such a thick layer this "basement membrane" must include not only the thin basal lamina lying immediately next to the epithelial cells, but also a deeper thicker, layer of fine reticular fibrils embedded in a condensation of ground substance.