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34 Cards in this Set
- Front
- Back
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What are the general layers of the Digestive system? |
Mucosa- Epithelium, Lamina propria (LCT, lymphatics, glands), Muscularis Mucosae Submucosa (DICT with blood vessels, lymphatics and nerves, Meissner's plexus, glands only in esophagus and duodenum) Muscularis Externa (Myenteric plexus) Serosa/Adventitia
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What are the actions of the inner circular and outer longitudinal muscles? |
Inner Circular - luminal constriction Outer Longitudinal- longitudinal constriction |
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Oropharynx- layers |
Mucosa Epithelium- stratified squamous, non-keratinized Lamina Propria- LCT+elastic fibers, mucous glands, PROMINENT elastic layer to anchor mucosa No muscularis mucosa No submucosa Muscularis externa: inner circular, outer long. skeletal muscle Adventitia (fibrosa): fibroelastic connective tissue layer |
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Esophagus- layers |
Mucosa Epithelium- stratified squamous, non-keratinized Lamina Propria- LCT with mucosal or cardiac glands near lower part (simple branched tubular) Muscularis mucosa- single longitudinal layer Submucosa DICT Compound tubuloalveolar glands - mostly mucosal and some serous for lysozyme Muscularis Externa Inner circular and outer longitudinal. Upper 1/3= skeletal, lower 1/3 smooth muscle Adventitia Loose connective tissue |
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Major change in epithelium from esophagus to stomach |
stratified squamous to simple columnar |
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What are the types of glands in the stomach and their locations? |
Cardiac glands- cardiac region Fundic glands- body/fundus region Pyloric glands- pyloric region |
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What are the mucosal/submucosal characteristics unique to the stomach? |
- Temporary submucosal folds = rugae (also fold mucosa) - Bulging mammilated areas or gastric areas= increase SA for secretion - Gastric pits (depressions in the mucosa) |
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In the lamina propria of the stomach what is between the glands in the submucosa? |
LCT with plasma cells, macrophages, blood vessels, lymphocytes, eosinophils, mast cells, macrophages |
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Layers of the stomach |
Mucosa Epithelium- simple columnar with gastric pits lined with surface mucous cells that secrete mucous Lamina propria- LCT + mucosal gland which will empty into the gastric pit Muscularis mucosa- smooth muscle helping secretions of gland to enter gastric pit Submucosa DICT and Meissner's plexus No glands Muscularis Externa Three muscle layers - inner oblique, middle circular, outer longitudinal. Myenteric plexus between middle and outer Serosa |
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Which type of gland has the characteristic two-tone staining appearance? |
Gastric glands due to their multiple cell types |
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What is the primary cell type in cardiac and pyloric glands? |
Mucous cells |
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What are the types of cells in the gastric gland? |
- Mucous neck cells - Parietal cells - Chief cells - Enteroendocrine cells - Gastrin cells - Undifferentiated stem cells |
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What is the produce of mucous neck cells? Where are they usually located? |
mucinogen; usually located in neck of gland |
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Histologically what do the parietal cells look like and why? |
They appear acidophilic due to their abundant mitochondria |
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What are the secretions of the parietal cell? |
HCl into the lumen through H+/K+ ATPases and tubulovesicular membranes that fuse to form canaliculi Gastric intrinsic factor (GIF) - complexes with vitamin b12 to allow its absorption |
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What stimulates the secretion of HCl by parietal cells? |
Acetylcholine, histamine and gastrin |
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How would you treat heartburn? |
Histamine antagonist= will not stimulate secretion of HCl from parietal cells |
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What is responsible for the basophilic appearance of chief cells? |
Large amounts of RER and golgi complexes |
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What is the main secretion chief cells and what causes its' transformation? |
Pepsinogen granules (in apical region) released into the lumen; converted to pepsin through acidic gastric juice |
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What is the difference in granule release between chief cells and enteroendocrine cells? |
Chief cells- apical- near lumen Enteroendocrine- basal- near lamina propria |
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What is the form of hormone secretion of enteroendocrine cells? |
merocrine- but can be released as paracrine or true endocrine |
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What is the difference between open and closed types of enteroendocrine cells? |
Open= contact lumen Closed= Don't contact lumen |
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What types of stimulants do enteroendocrine cells respond to? |
- pressure, luminal contents, neuroendocrine stimulation |
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What kind of staining do enteroendocrine cells show up in ? |
Chromaffin cells, argentaffin, argyrophilic stain silver |
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What are the different of enteroendocrine cell products that affect the stomach? |
Produced by stomach: - somatostatin - gastrin Produced by intestine: - secretin - gastric inhibitory peptide - motilin |
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What are the different effects of the products of enteroendocrine cells to the stomach? |
somatostatin- inhibits gastrin cells gastrin cells (localized in pyloric region)- stimulate HCl secretion by parietal cells secretin & GIP- inhibit gastric acid secretion motilin- increases GI motility |
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Where are undifferentiated stem cells located? What is their function? |
Base of pits and neck of glands Renew surface epithelium every 3-5 days Renew cells in glands about every 180 days |
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What types of cells are present in cardiac glands? |
mucous cells, enteroendocrine, mucous neck cells, undifferentiated stem cells |
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What do the mucous cells in the pyloric glands generally secrete? |
Mucus and lysozyme |
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What is the difference between the emptying of the cardiac and pyloric glands? |
Pyloric empty into long pits, and cardiac empty into short pits |
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What are the cell types located in the pyloric glands? |
enteroendocrine (gastrin-producing), mucous neck cells, undifferentiated stem cells |
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What is unique about the lamina propria surrounding the pyloric glands? |
They contain more lymphatic tissue than other areas. |
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How does the penetration of H. pylori occur and what are the consequences? |
- H. pylori produces ammonia through urease and neutralizes acidity of stomach enough to allow bacteria to survive - Excess acid is secreted due to its inhibition of somatostatin, gastrin increase, leading to gastric ulcers with bleeding |
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What is the difference in mucosa thickness between cardiac and pyloric glands? |
Pyloric glands have thicker mucosal layer than cardiac. |
