The cells in the bright red layer and in the pale layers above it are completely flattened and dead, and have lost their nuclei. These glands have ducts that empty into the lumen of the gut. Simple tubular glands of gut wall seen in low power. These glands are lined with epithelium throughout their whole extent. Slide 27 Detail of such a gland.
Goblet cells are purple here.
Ducts and alveoli are lined with epithelium. Notice that the nuclei of mucous cells are dark and flattened at the base of the cells, while the nuclei of serous cells are round and more centrally located at their cells.