colon
In the colon, mucin-containing goblet cells and columnar epithelial cells can be readily identified. The luminal openings of the crypts appear in the horizontal axis as black holes projecting onto the surface of the mucosa, and each crypt is covered with a layer of epithelial cells.
The microvascularization is highlighted within the lamina propria in deeper parts of the mucosal layer. The vasculature within the mucosa of the colon shows a typical honeycomb appearance that represents a network of capillaries. Red blood cells are not labeled by fluorescein, and appear as moving black dots in the lumen of the vessels.