Exam 3 Review:  Chapter 23:  Intestinal Histology

lacteal - The minute intestinal lymphatic vessel, found in the interior of each intestinal villus, which receives chylomicrons, lipids absorbed from chyle and modified by the simple columnar cells which line the small intestine, these chylomicrons will be transported from the lamina propria of the small intestine to the lymphatic circulation and thereby to the thoracic duct.

microvilli - The minute hair-like or finger-like projections of the outer cell membrane which increase the surface area of the outer cell membrane of certain types of epithelial cells, e.g., the simple columnar cells which line the small intestine, the cubiodal cells of the proximal convoluted tubules of the nephron in the kidney, etc.

brush border - A thin layer of specialized cell membrane, faintly visible in the light microscope, on the apical surface of certain types of epithelial cells; in some cases, it is formed by microvilli, e.g., the simple columnar cells which line the small intestine, the cubiodal cells of the proximal convoluted tubules of the nephron in the kidney, etc.; in other cases, it is formed by cilia, e.g., the pseudostratified columnar epithelium of the respiratory tree, the cells lining the ovarian ducts, etc.

intestinal glands - The simple tubular exocrine secretory structures of the intestinal mucous membrane formed by extension of layer of simple columnar cells which line the small and large intestine; mucus-producing goblet cells, other glandular secretory cells and small numbers of enteroendocrine cells are present.

paneth cells - Specialized granular secretory cells with large acidophilic-staining nuclei found in the depths of intestinal glands in the small intestine which secrete lysozyme and other anti-bacterial compounds.

duodenal glands - The compound tubular exocrine secretory structures of the submucosa of the duodenum; they contain mucus-producing cells which release bicarbonate ions; this alkaline mucus assists in neutralizing the acidic chyme from the stomach (as does the alkaline pancreatic juice).

solitary lymphatic nodules - Isolated minute round to oval collections of lymphoid tissue (T lymphocytes and B lymphocytes, especially those capable of secreting IgA) found in the mucosa of the small and large intestines, containing only a single follicle with germinal center, if any; especially common in the cecum and appendix; an example of MALT = mucosa-associated lymphatic tissue.  [See a solitary lymphatic nodule in the wall of the esophagus below.]

aggregated lymphatic nodules - Clusters of minute unencapsulated masses of lymphoid tissue (T lymphocytes and B lymphocytes, especially those capable of secreting IgA) found in the mucosa of the small and large intestines, containing numverous follicles with germinal centers; especially common in the jejunum and ileum; an example of MALT = mucosa-associated lymphatic tissue.  aka - Peyer's Patches  [See aggregated lymphatic nodules in the wall of the ileum below.]

 1.