What are the tissues present in small intestine?

The small intestine is a muscular tube lined by a mucous membrane. The mucous membrane is composed of several layers of tissue, including:

* Epithelium: The epithelium is the innermost layer of the mucous membrane and is made up of a single layer of columnar cells. These cells are responsible for absorbing nutrients from food and secreting mucus.

* Lamina propria: The lamina propria is a layer of connective tissue that lies beneath the epithelium. It contains blood vessels, lymphatic vessels, and nerves.

* Muscularis mucosae: The muscularis mucosae is a thin layer of muscle that lies beneath the lamina propria. It helps to move food along the small intestine.

* Submucosa: The submucosa is a layer of connective tissue that lies beneath the muscularis mucosae. It contains blood vessels, lymphatic vessels, and nerves.

* Muscularis externa: The muscularis externa is the outermost layer of the small intestine and is made up of two layers of muscle. The inner layer is composed of circular muscle fibers, while the outer layer is composed of longitudinal muscle fibers. These muscles help to move food along the small intestine.

In addition to these layers of tissue, the small intestine also contains a number of glands, including the Brunner's glands and the crypts of Lieberkühn. Brunner's glands secrete mucus, while the crypts of Lieberkühn secrete digestive enzymes.