BIOL 221 Lecture Notes - Lecture 8: Dense Irregular Connective Tissue, Muscularis Mucosae, Submucous Plexus
4 Mar 2020
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Document Summary
The lamina propria consists of areolar connective tissues in which abundant blood capillaries and lymphatic capillaries called lacteals are found. The muscularis mucosae consists of smooth muscle and lies outside the lamina propria. The muscularis mucosae helps hold the muscularis in folds. The submucosa consists of dense irregular connective tissue. It is highly vascularized and has many lymphatic vessels (topic 5). Lymphoid nodules include peyer"s patches in the small intestines. There is also a large amount of diffuse lymphatic tissue included as part of the mucosa-associated lymphatic tissue (malt). The submucosal plexus consists of sensory and motor neurons; it innervates the mucosa, muscularis mucosae and submucosal glands. The muscularis externa, also known simply as the muscularis, consists of two layers a circular layer and a longitudinal layer through most of the digestive tract. The stomach has an additional layer that runs obliquely. These layers of muscle are responsible for waves of motion called peristalsis.
