Colon - low power
Colon (high power)
Each section of the GI tract has tunics, (mucosa, submucosa, muscularis_externa, and serosa) and each section has unique specializations associated with these tunics. For example, the submucosa of the duodenum, which is the first section of the small intestine, contains duodenal (Brunners) glands. The submucosa of the ileum, which is the last section of the small intestine, contains numerous and obvious lymphoid nodules (Peyers_patches).
The mucosa of each section of the GI tract includes the epithelial surface, known as the lamina_propria and a thin bottom layer (muscularis_mucosae) composed of smooth muscle fibers, which is the border between the mucosal and submucosal layers. In the stomach there are gastric_pits, which are the deep empty spaces positioned between the protruding sections of epithelium, and gastric_glands, which are visible in the mucosal layer as well.
The colon is the large intestine. It begins at the ileocecal_valve, which is also the terminal point of the ileum, or last section of the small intestine. The outstanding epithelial feature of the colon is the tremendous number of goblet_cells. Once again you can also observe the intestinal_crypts (crypts_of_Lieberkuhn), as well as the presence of the lamina propria.