The villi of the mucosa have the following characteristics

The villi of the mucosa have the following characteristics...

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The villi of the mucosa have the following characteristics:  An outer epithelial layer (facing the lumen) consists of the following cell  types: Absorptive cells, the primary cell type of the epithelial layer,  synthesize digestive enzymes called brush border enzymes that become  embedded in the plasma membranes around the microvilli. Various  nutrients in the chyme that move over the microvilli are broken down by  these brush border enzymes and subsequently absorbed. Refer to Table ,  earlier in this chapter, for a list of these enzymes.  Goblet cells, located throughout the epithelial layer, secrete mucus  that helps protect the epithelial layer from digestion. Enteroendocrine cells  secrete hormones into blood vessels that  penetrate each villus. 
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Unformatted text preview: Paneth cells, located in the epithelial layer facing the intestinal crypts, secrete lysozyme, an enzyme that destroys bacteria. An inner core of lamina propria (connective tissues) contains blood capillaries and small lymphatic capillaries called lacteals. The submucosa that underlies the mucosa of the small intestine bears the following modifications: Brunner's (duodenal) glands, found only in the submucosa of the duodenum, secrete an alkaline mucus that neutralizes the gastric acid in the incoming chyme. Peyer's patches (aggregated lymphatic nodules), found mostly in the submucosa of the ileum, are clusters of lymphatic nodules that provide a defensive barrier against bacteria....
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This note was uploaded on 11/10/2011 for the course PT 101 taught by Professor Staff during the Spring '10 term at Texas State.

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