Goal 6 (c-f): Histology Of The Stomach Flashcards
What are the 4 layers of the stomach?
MSMS (inner to outer)
- Mucosa
- Submucosa
- Muscularis externa
- Serosa
What are the components of the Mucosa layer?
- Epithelium
- Lamina Propria
- Muscularis Mucosa
What are the components of the Submucosa?
- Submucosal Gland
- Submucosal nerve plexus= Meissner’s plexus
What are the components of the Muscularis Externa?
- inner circular layer
- myenteric nerve plexus= Auerbach plexus
- outer longitudinal layer
What are the 3 regions of the stomach? What are the names of the glands of each?
- cardiac region: deep pits, wide cardiac gland lumen
- pyloric region: deep pits, wide pyloric glands
- fundus region: shallow pits, narrow fundic glands, main secretory part of stomach and largest stomach section
What are gastric pits? Surface mucus cells? Rugae?
- gastric pits: see with microscope, openings in mucosa, bottom of it are gastric glands
- surface mucous cells: lime the inner surface of stomach and gastric pits, secrete insoluble viscous gel like mucus coat that has a lot of bicarbonate (protect against injury of gastric wall)
- rugae: Submucosal folds that allow stomach to distend when filled
What cells protect gastric wall against chemical injury? How?
- surface mucus cells
- rich in bicarbonate: bicarb is alkaline in nature, nullifies the acid
What are the 5 fundic gland cell types?
- mucus neck cells: soluble low alkaline secretions
- Parietal/oxyntic cells: HCL and B12 intrinsic factor
- chief/peptic/zymogenic cells: pepsinogen
- Enteroendocrine cells (DNES): hormones by paracrine or endocrine process
- stem cells: precursors of all cells if needed
How often does the entire lining of the stomach get replaced?
4 days (3-5 days technically)
What are Parietal/Oxyntic Cells? Why does it produce? What happens if they’re damaged?
- large acidophillic cells in cytoplasm, studded with mitochondria so deal with proton pumps and ATP
- produce HCL (hydrochloric acid) and gastric intrinsic factor(proteins that binds to b12 to help it get absorbed by ileum)
- lack b12, get PERNICIOUS ANEMIA
What is Achlorhydia? Why is this bad?
- no HCL, which a component needed to make gastric acid as acidic as it is
- no acid in stomach, no protection from bacteria. INFECTIONS
What are Peptic/Chief cells? Where do they come from? Basophilic or acidophillic?
- protein secreting cells, secrete pepsinogen and a weak lipase. Once it reaches the gastric juice, it’s changed to pepsin (enzyme that breaks down proteins)
- from rER, go through Golgi after
- basophilic (purple colored)
What type of epithelium for esophagus? Stomach? At what point goes the type of epithelium between the two abruptly end?
- esophagus: stratified squamous non keratinized
- stomach: simple columnar epithelium
- ends at the GASTROESOPHAGEAL JUNCTION
What are all the digestive enzymes secreted from gastric glands?
- Renin and lipase
- pepsin: from chief cells
- HCL: parietal cells
What are the 3 components of the gastric mucosal barriers?
- viscid mucus layer: surface cells secrete it
- bicarbonate ions: surface epithelial cells secrete it to maintain ph in stomach
- compact epithelial cell: tight junctions here
