G.I.T. 1 Flashcards
3 identifiers for the esophagus
- submucosal glands
- mixture of sk. mus. and smooth mus.
- only adventitia b/c passes through thoracic mediastinum
rugae
submucosal folds of the stomach
3 identifiers of stomach
- no villi
- domed/pitted mucosa profile (cobblestone)
- little lamina propria due to dense mucosal glands
lumen to distal components of the mucosal tunic
epithelium, lamina propria (loose CT), muscularis mucosa
inward from the lamina, what are the muscularis externa components of stomach
oblique (fundus region), circular, longitudinal
stomach mucosal epithelium
simple columnar
defining feature of the duodenum
Brunner’s Glands- SUBMUCOSAL glands that make alkaline mucous (bicarbonate) to combat the acidity of the stomach chyme (pH 2 –> made to pH5)
defining feature of the ileum
Peyer’s patches
epithelium of colon
simple cuboidal (many goblet cells)
outer-most layer of the GI tube
adventitia- areolar CT that attaches to local viscera OR
serosa- serous-secreting simple sq. epith. that gives mesenteric support
cardiac glands
mucus-secreting in the beginning and end of esophagus, lamina propria mucosal layer
pyloric sphincter
thickening of circular smooth mus. between stomach and duodenum
Where are Auerbach’s (myenteric) plexuses found
muscularis externa
Modification unique to the colon
taeni coli- 3 bands of longitudinal muscularis externa
foveolae
separation from the gastric pit to the gastric glands
glands of esophagus and their locations
- cardiac- lamina propria (@ start and end of esophagus)
2. esophageal glands proper-submucosal
how many glands per gastric pit
3-4
the cell types of a gastric gland from the lumen downward
mucous neck cells, undifferentiated neck (stem) cells, parietal cells, chief cells, and enteroendocrine cells
4 features of Parietal cell appearance
large round/ triangular, central nucleus, acidophilic (pale pink) cytoplasm, with CANALICULI on apical surface
Parietal/oxynic cells secrete…
HCl, intrinsic factor glycoprotein for B12 absorption (erythrocyte maturation)
Chief/zymogen/peptic cells secrete…
pepsinogen, rennin
Mucous neck cell appearance
nucleus is flattened along the BM
What is the difference between mucous neck cell and Stomach Epithelial Cell sectretions
mucous neck cell gives acidic mucin, SEC gives neutral mucin
the three regions below the foveolae
isthmus, neck and base of gastric gland
plicae circularis (valves of Kerckring)
submucosa base of villi - longest in jejunum
the two varieties of simple columnar epithelium of sm intestine
- absorptive ENTEROCYTE
2. goblet (increasing from duodenum to ileum)
name of mucosal glands in the sm. intestines
crypts of Lieberkuhn
describe the core of villi outward
lacteal and capillaries, [then sm. mus.,] then lamina propria, then epithelium
why is there no serosa on the duodenum
it lies retroperitoneal (only adventitia)
pH of goblet cell mucin ( sm. intes.)
low
myenteric plexus
Auerbach’s - between mus. externa, many nerve bodies
purpose of Paneth cells
anitmicrobial (lysozyme, Tumor necrosis factor-α and defensins secreted)
3 types of entero-endocrine in the sm intestine
Cholecystekinin (CCK), gastric inhibitory peptide, secretin
where are chylomicrons produced
in sER of enterocytes
largest endocrine organ of the body
enteroendocrine cells of stomach thru colon
closed enteroendocrine cells
hormones do not reach the lumen- detect distention of the STOMACH
gastrin-producing cells
stimulate acid and pepsinogen release in stomach
CCK
cholecystekinin, endocrine cell of sm intes. increases pancreatic sectretion, gallbladder and pyloric sphincter contraction
what two endocrine cells combat gastrin producing cells & how?
somatostatin- producing in stomach- directly, GIP: gastric inhibitory peptide, of sm intes.- decreases acid production and motilin
Secretin
endocrine cell of sm intes. secreted in presence of acid and fatty acid. stimulates bicarbonate release from pancreas, insulin release from B cells of Langerhans
what is the structural functional unit of the stomach?
the gastric gland
open type enteroendocrine cell
in the SM INTESTINES to detect conditions of the lumen [ex: lipid presence and signal for increased lipase production]
what is the only cell type that can be found in both the stomach and in the sm intestines
enteroendocrine