Flashcards in Glands, cells, hormones Deck (27):
in the gastric pit, where are the surface mucous cells located?
in the "pit" i.e opening of the pit, area
in the gastric pit, where are parietal cells located?
in the neck region
this region is known as the "isthmus"
in the gastric pit, what cells are in the body?
chief cells predominate followed by enteroendocrine cells,
Mucous cells of the fundus
what is their mucous made from
two types: mucous neck cells and the mucous surface cells
neck cells are located in the opening of the pit
mucous is made from 95% water and % mucins
mucous layer traps bicard inons and neutralixes microenvironment adjacnte to the apical region of the surface mucous cells to an alkaline pH
predominate in the lower third of gastric pit
no present in cardiac region, not found in pyloric antrum
in apical regions, contains pepsinogen secretory granules.
pepsinogen is a proenzyme
converted in acidic environment to a proteolytic enzyme
exocytosis of pepsinogen is rapid, stimulated by feeding
gastric glands of the fundus region contain two major cells
chief cells (peptic) and parietal cells
also called oxynitic cells. secrete HCL and intrinsic factor.
after stimulation, vesicles fuse with apical membrane.
carbonic anhydrase AND "H, K-ATPase" is localized into microvilli projecting into the lumen of the intracellular canaliculus.
What receptors are on the bottom of a parietal cell?
histamine receptor, ACh receptor, and gastrin receptor
pepsinogen can be released by stimulation of what neurotransmitter
caused by antibodies to H,K-ATPase, in the parietal cell, and intrinsic factor
destruction of parietal cells causes a reduction in HCL ("achlorhydria") and a lock of synthesis of intrinsic factor
result: B vit 12 deficiency disrupts formation of red blood cells in bone marrow
a patient is achlorhydriia and anemic, what is a possible problem? what would be suitable treatment?
she has autoimmune gastritis, requiing Vit B 12 supplimentation
how HCL secretion works in parietal cells
parasympathetic stimulation via ACh and the peptide gastrin, produced by enteroendorcrine cells of the pyloric antrum, stimulate parietal cells to secrete HCL
ACh stimulate also stimulates gastrin release
gastric juice contains two protective layers
an alkaline mucosa and an acidic gel (HCL and PEPSIN).
where does helicobacter pylori reside and under what conditions?
in the pyloric antrum region, under both the alkaline conditions of the mucosal gel and the acidic environment above it.
h pylori produces what
is is associated with peptic ulcers
peptide hormones produced by the GI endocrine cells have the following functions
regulation of water, electrolyte metabolism, and enzyme secretion
regulation of GI motility and mucosal growth
stimulation of the release of other peptide hormones
released by cells in the duodenal glands of lieberkuhn when gastric content enters the duodenum
secretin stimulates pancreatic and duodenal bicarb (from brunners glands)
brunners glands release ___ from stimulation by
bicarbonate from stimulation by secretin
____ together with CCK stimulates growth of exocrine pancreas
secretin stimulates ______ cells to release a proteolytic enzyme, and inhibits _____ release and reduce HCL
chief cells, gastrin release
produced by G cells located in pyloric antrum
there are three forms
main function is to stimulate function of HCL from parietal cells
can also activate CCK to stimulate gallbladder contraction
produced in duodenum
stimulates gallbladder contraction and relaxation of sphincter of Oddi when proteins and fat rich chyme enters duodenum
glucose dependent insulinotropic peptide
formally called gastric inhibitory peptide, produced by duodenum, stimulates insulin release when glucose detected in small intestines
how do you distinguish pyloric glands from cardiac and gastric glands
they're much more tortuous
simple tubular and branched
muscularis externa of stomach
three layers, inner most circular, internal oblique, longitudinal directions