Histology of stomach and intestines Flashcards
three regions of stomach glands and differences b/w them
cardiac and pyloric have fewer parietal, chief and enteroendocrine cells than fundic area. They have more mucous cells. Deeper pits (greater pit:gland ratio)
five types of cells in stomach and where you find them
surface mucous: on surface or in gastric pits. Neck mucous: neck of gastric glands. Parietal: in gastric glands, secrete HCl and IF. Chief: basal half of glands, secrete pepsinogen. Enteroendocrine: release hormones from basal side which modulate digestion, scattered.
layers of muscle in stomach
inner oblique, middle circular, outer longitudinal
unique features of parietal cells
lots of mitochondria, secretory canaliculus
appearance of chief cells on stain? mucous? parietal?
darker staining. washed out. pink and puffy relative to neighbors
three surface area increasing features of small bowel and what they’re made of
plicae circularis (submucosa and mucosa), villi (mucosa), microvilli (plasma membrane)
where do you find stem cells in stomach and intestine
in the neck of gastric glands and crypts of Lieberkuhn
process of lipid digestion and absorption
Emulsified by bile salts and lecithin, broken down by pancreatic lipase. Micelles diffuse into cell, are made into triglycerides and packaged into chylomicrons which are discharged into intercellular space and taken up by lacteals or capillaries
process of protein digestion and absorption
pepsin cleaves proteins into polypeptides. Pancreatic trypsin, chymotrypsin and carboxypeptidase produce free AAs. Taken up by active transport
process of carbohydrate digestion and absorption
salivary amylase, pancreatic amylase. Brush border sucrase, maltase, lactase and aminopeptidase. Glucose and galactose taken up via Na dependent active transport
Paneth cells
in base of crypt. secrete antibacterial lysozyme
Role of CCK
most important in duodenum. Signals pancreas and gallbladder to do everything.
M (microfold) cells
take up microorganisms (and IgA?) via transcytosis. Overly peyer’s patches
Brunner’s glands: where?
duodenum in submucosa
where do you see peyer’s patches?
ileum below the epithelium
