Large intestine

The large intestine starts with the cecum, a large pouch that absorbs fluids and salds that remain after the intestinal digestion is compleated. Cecum is follwed by the spiral colon that transitions into rectum.

Since the large intestine has no villi or plica circularis the mucosa is smooth. Simple tubular intestinal glands (crypts of Lieberkuhn) extend through the entire thickness of the mucosa. The surface columnar epithelium and the cells lining the crypts are enterocytes, with an oval basal nucleus and apical brush border, the microscopic representation of microvilli. There are also numerous mucous secreting goblet cells recognized by their content of a large mucous globule. The lamina propria with connective tissue and inflammatory cells surround the crypts. A thin smooth muscular layer, the lamina muscularis mucosa marks the border between the mucosa and submucosa.

The submucosa consists of loose connective tissue with blood vessels and nerves. Some solitary lymph follicles are also seen in large intestine.