Histology - Stomach, Small and Large Intestine Flashcards
Large Intestine - ▪ Enterocytes ▪ Goblet cells
▪ Enteroendocrine cells ▪ M cells (antigen-transport)
NO paneth cells.
Small Intestine
Appendix with prominent GALT - numerous lymphatic nodules.
Oblique, circular, longitudinal layers of muscularis externa in stomach.
Esophagus epithelium - Simple Squamous, Non-Keratinized.
Gastritis in lamina propria (Loose CT inflammation)
Enteroendocrine cells - found at stomach glands, mostly at their base.
Fundus and Body with fundic glands, surface, stem cells, muscous neck cells, parietal cells, chief cells, enteroendocrine cells.
Parietal cells - (HCl secretion) - acidophilic, proton pumps, canaliculi, tubulovescular membranes - secreting acid.
Chief Cells - ABC - apical, basophilic, chief cells
Esophagogastric junction with esophageal cardiac glands - mucus secreting glands in the laminal propria of the lower esophagus.
Enteric nervous system (ENS) - regulates motility, secretion, blood flow. Responds to mechanical, chemical ANS stimuli.
Peyer’s patches - large accumulations of GALT in the lamina propria of ILEUM - may extend into submucosa.
Cardicac Gland - pale, alkaline
Muscularis Mucosae - agitates luminal contents, aids gland expression. Smooth muscle. Same innervation as glands.
Brunner’s glands (or duodenal glands) found in the duodenum which is above the hepatopancreatic sphincter. Produce a mucus-rich alkaline secretion (containing bicarbonate) in order to: protect the duodenum from the acidic content of chyme;
provide an alkaline condition to activarte intestinal enzymes, and lubricate the intestinal walls.
Appendix with mucosa, lamina propria, submucosa, lymphatic nodule
PS is pyloric sphincter - thickening of circular layer of muscularis externa
Appendix - Promitent GALT
Enteroendocrine cells - basal SGs, fundic gland.
Secrete hormones like gastrin, CCK, secretin
Regulate gastric, intestinal, pancreatic, gallbladder activity.
Ileocecal junction
Adhesion of serosa or adventitia. Clinical application, fubrous scar tissue, type 1 collagen.
Large intestine - simple columnar, intestinal glands and goblet cells that secrete mucus for lubrication and protection.
Pyloric Gland
GALT - plasma cells, protection, abundant in ileum and appendix
Rectoanal Junction - Transition from simple columnar to stratified columnar to stratified squamous non keratinized
Top to Bottom - Mucosa, GALT, submucosa, Muscularis externa, serosa
Mucosa, lamina propria. (Loose CT, fenestrated cap, glands, GALT)
Small Intestine - with intestinal folds, villi.
Paneth Cell - epithelium of the small intestine located just below the intestinal stem cells in the intestinal glands (in the crypts of Lieberkühn). Large granules that consist of anti-microbial compounds important in immunity and host-defense.
Stomach - Pylorus - numerous glands
Stomach rugae.
Fundus (or body) of Stomach with surface mucous cells and neck cells - aka Fundic Glands within the lamina propria of fundus and body.
Paneth Cell - epithelium of the small intestine located in the intestinal glands (in the crypts of Lieberkühn). Large granules that consist of anti-microbial compounds important in immunity and host-defense.
Upper third muscularis externa in esophagus. Skeletal swallowing. Lower motor neurons, vagus nerve. neuromuscular synapse, upper esophageal sphincter.
Esophagus - Esophageal glands in submucosa lubricate and protect GI wall from self-digestion.
Intestinal glands (crypts of Lieberkühn) contains multiple types of cells: enterocytes (absorbing water and electrolytes), goblet cells (secreting mucus), enteroendocrine cells (secreting hormones), and at the base, Paneth cells (secreting anti-microbial peptides) and stem cells.
The black bracket is the mucosa; the blue bracket is the submucosa; the red bracket is the muscularis; the green arrow indicates the serosa.
Submucosa - Dense CT aids in supprt, tension. Larger vessels, give rise to capillaries. Submucosal Plexus. Involved in metastasis (lymph vessels) and hemorraging (ulcer).
Stomach
Epithelium: simple columnar
Mucosal glands: fundic, cardiac, pyloric glands
NO submucosal glands.
Small intestine with enterocyte, goblet cell, smooth muscle, and a central lacteal.
Duodenum with Brunner’s Glands above the hepatopancreatic sphincter (Sphincter of Oddi). The main function of these glands is to produce a mucus-rich alkaline secretion (containing bicarbonate).
Large Intestine - OL is outer longitundinal folded up to become teniae coli
Large Intestine Mucosa - no villi, plenty of glands in LP. Abundant goblet cells. Similar to small intestine, but NO paneth cells.
Small Intestine with circular folds and villi.
Villus epithelium: ▪ Enterocytes ▪ Goblet cells
Villus lamina propria:
▪ Lacteals: lymphatic capillaries, uptake chylomicrons (modified triglycerides)
▪ Fenestrated (type II) capillaries: uptake of other molecules
▪ Smooth muscle: contract villi; fluid enters lacteals
▪ GALT: immune response
Middle third transition of esophageal muscularis externa.
ENS Myenteric Plexus - regulates peristalsis (muscularis externa)
Muscularis Externa - Myenteric Plexus regulates peristalsis. Clinical - dysmotility and T2 carcinoma.
