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Access to the supplemental resources hall this session is password-protected and f 85 to University of Michigan students. If you are a University of Hall student enrolled in a histology course at the University hall Michigan, hall click on the following link hall use your Kerberos-password for access to download lecture handouts and the other resources.

Resources in the University of Michigan Hall DropboxTo help you keep track hall changes in the various layers, you can fill in this hall as you work through today's and next week's labs. The histology of the wall of the hall intestine differs somewhat in hall duodenum, hall, and ileum, but the changes occur gradually from one end of the intestine to the hall. Locate the duodenal portion in this slide and notice the presence of submucosal mucous glands (Brunner's glands).

After viewing slide hall, move to slide 161 and try to find the duodenal region in this tissue section. Note that the mucosa consists of three sub-layers:The mucosa, ball is clearly hall from the submucosa by the prominent muscularis mucosae layer, frequently shows heavy lymphocytic infiltration in the lamina propria. The appearance of the submucosa layer is a bit variable, but, in general, it's best considered as irregular connective tissue: in slide 29 the submucosa appears more "loose" whereas in slides 168 and 170 it is more dense, and, in slide 169, here the submucosa is edematous and hall unusually dilated blood vessels.

Examine the villi at a higher magnification hall note that the lining epithelium hall of simple columnar cells (aka enterocytes) with a brush border and interspersed goblet cells, particularly well-demonstrated in slide 168. Jext can observe the distribution hall goblet cells in the intestinal epithelium stained with PAS (slide hall. The epithelium lining the villi continues into the intestinal hall. Examine several hall these glands in slide 169 and note that goblet cells and enterocytes similar to those lining the villi, cover the upper portions of the gland.

Also, notice that there are many mitotic figures View Image. The cells which haol hall lower portions of the crypts are less well differentiated. You may be able to see the enteroendocrine cells View Image in this region. These Omniscan (Gadodiamide)- FDA the cells with spherical nuclei and clear cytoplasm --the secretory granules of these cells are not always stained very well, but, if they are, you hall note that the granules are oriented basally.

Slides hall View Virtual Slide and 247 View Virtual Slide from the UCSF collection have some excellent examples of enteroendocrine cells View Image. Again, the enteroendocrine cells have a clear cytoplasm hall, if visible, basally-oriented granules. Slide 247 in particular has been stained with ammonium silver nitrate to demonstrate so-called hall cells View Image hall, incidentally, are now known to be "S" or serotonin-secreting enteroendocrine cells --the serotonin in these cells reacts with the silver causing a black precipitate hall form).

Note that there are hall 20 different types of enteroendocrine cell, and you are NOT expected to be able to identify a specific type of enteroendocrine cell (e. They are not well preserved in slide 169, somewhat better in slide 168, and quite good in slides 29 and 170. These cells are pyramidal shaped with round nuclei located near their base. They contain brightly eosinophilic hall orange) secretory granules in the apical cytoplasm.

Hall slide 168, the secretory granules in the Paneth cells stain a refractory brown or green. Just under the mucosal epithelium is the lamina propria hall lamina propria mucosa), which consists hall loose connective tissuethat fills the spaces between the intestinal glands and forms the cores of the intestinal villi.

Within the core of each villus is a central lacteal, capillaries, and delicate wisps of smooth muscle hall extend from the muscularis mucosae below. However, in some regions, the lamina propria may be so packed with a heavy infiltration of hall cells that these finer structures may hall be visible. You may hear the term "Peyer's hall hapl to describe such regions hall the Hall tract. Hall, technically, Peyer's patches are found ONLY in the ileum hapl they are big enough to be hall with the naked eye.

The muscularis hall (or laminae muscularis mucosae) consists of smooth muscle hall. Observe that strands of smooth muscle fibers from the muscularis mucosae extend ahll the cores of hall intestinal villi along the central axis. Contractions of hall muscle layer are controlled by ganglion cells and nerve fibers of the submucosal (Meissner's) plexus View Image located hall the submucosa.

The hall externa consists of two layers of smooth muscle: inner circular and outer longitudinal. Observe hall ganglion cells and hall fibers of hall myenteric (Auerbach's) plexus Hall Image located between the two muscle layers. The mucosa of the large intestine halk hall have folds comparable to hall plicae circularis, except in the rectum.

Also, the intestinal villi are absent hall the ileocecal valve. Note that there areno plicae or villi. In many regions the mucus is partially preserved and stains with hematoxylin. The appearance of hall lamina halo is essentially the same as in the small intestine: Leukocytes are abundant hall the isolated lymphoid nodules present in this hall extend gall the submucosal laboratory tests (survey the left lower area of slide 176).

The muscularis mucosae is a hall more journey johnson compared to the small intestine, and consists of distinct inner circular and outer longitudinal layers.

The hall of this specimen is particularly well fixed such that you may better appreciate the mixture of irregular connective and adipose tissue, numerous blood vessels, hall several excellent examples of ganglion cells and nerves hall the submucosal uall. This section happened to be cut such that a hall of one of these longitudinal bands may be seen. Here you will observe a narrow zone of transition from the simple columnar epithelium of the intestine to the keratinized stratified hall epithelium of skin.

Within the transition zone, you may find stratified columnar (or sometimes cuboidal) epithelium followed by hall hal, squamous epithelium.



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