Histology of the digestive tract Flashcards
Explain the secretory structures of the stomach
Gastric epithelium secretes hydrochloric acid, digestive enzymes and mucus.
The surface area is increased by downgrowths that form glands: Gastric glands
List the cells of the mucosa
Mucous cells
Acid producing cells - Parietal cells
Enzyme Producing cells - Chief/peptic cells
Stem cells - regeneration
Enteroendocrine cells
Explain the structure of gastric mucous cells
Surface mucous cells: Tall, columnar, basal nuclei, clear staining cytoplasm
Neck mucous cells: Smaller, less mucous, basal nucleus, finely granular cytoplasm, small mucin vacuoles
Explain the structure and function of parietal cells
Acid-producing cells
Large pyramidal cells with central nuclei and eosinophyllic cytoplasm
Produce HCl
What is the structure and function of chief cells
Enzyme secreting cells - pepsin
Large basal nuclei, eosinophyllic granules and rich rER
Pepsin breaks down proteins into small peptides and is responsible for conversion of solid food particles to fluid chyme
Explain the structure and function of chief cells
Enzyme secreting cells - pepsin
Large basal nuclei, eosinophyllic granules and rich rER
Pepsin breaks down proteins into small peptides and is responsible for conversion of solid food particles to fluid chyme
What is the structure and function of enteroendocrine cells
Small round cells on the epithelial basement membrane that have a round central dark staining nucleus with a rim of clear cytoplasm
Contain membrane-bound neurosecretory granules that secrete a variety of hormones
What are the 3 zones of the gastric mucosa
Superficial zone: Surface mucous cells - downgrowths
Neck zone: Narrow - immature stem cells, some neck mucous cells
Deep zone: Glands, close to muscle layer
Name the areas of the stomach
Cardia: Extends from lower end of esophagus into upper stomach
Pylorus: Lower 1/3
Body: Biggest part of stomach
Which modifications to the mucosa of the small intestine results in an increased surface area
Circular folds of mucosa and submucosa = plicae
Invaginations of mucosa between villi = Crypts of Liberkuhn
Name the 3 functional zones of the small intestine
Villi
Crypts
Neck zone (point where villi and crypts merge)
Explain enterocytes
Main cell of the small intestine and have an absorptive function
Tall columnar, round/oval nuclei in lower third of cell
Microvilli on luminal surface
Where can goblet (mucous) cells be found and what do they contain
Scattered amoung enterocytes
Mainly found in upper two-thirds of crypts
Globules of mucin in cytoplasm
Explain the location, structure and function of paneth cells
Found in lower 1/3 of crypts
Basal nuclei, large eosinophilic granules in cytoplasm
Contains defensins
Protect against infections
Explain the structure, location and function of paneth cells
Found in lower 1/3 of crypts
Basal nuclei, large eosinophilic granules in cytoplasm
Contains defensins
Protect against infections
