011615 normal structure Flashcards
what modifications in sm intestine increase surface area for absorption
plicae circulares
villi
microvilli
epithelial covering of the villi are composed of what cell types
absorptive cells (enterocytes) goblet cells enteroendocrine cells
crypts of lieberkuhn contain what kind of cells
goblet cells
enteroendocrine cells
stem cells
Paneth cells
microvilli in sm intestine are covered with what?
glycocalyx coat (protective roles and involved in digestion of disacchardies and dipeptides into monomers for adsorption through pepetide hydrolases and disaccharidases abundant on apical surface)
goblet cells are full of what?
carbohydrates that can be stained
role of goblet cells
secrete mucin
role of Paneth cells
secrete lysozyme secrete defensins (neutralize bacterial and viral infections)
Peyer’s patches are found most numerously where
ileum
duodenal submucosa differs from the rest of the GI tract due to the presence of what
Brunner’s glands (appear similar to mucous acini)–secrete alkaline mucus that neutralizes the pH of the gastric chyme and protects duodenum
the duodenum differs from the jejunum and ileum how
its villi are broader, taller, and more numerous per unit area
Brunner’s glands in submucosa
how does large intes differ from sm intes?
large intes doesn’t have plicae circulairs and villi. it has a relatively smooth surface
its crypts of Lieberkuhn are longer than in the sm intes and contain an abundance of goblet cells
what kinds of cells that are present in the sm intestine are actually absent in the large intes?
Paneth cells
characteristic feature of appendix
presence of masses of lymphoid tissue in mucosa and submucosa (forms follicles with germinal centers)
anus has what histological features
large circumanal glands
stratified squamous epithelium
venous plexi in submucosa (internal hemorrhoidal plexus and external hemor. plexus)
