lect 11- GI system Flashcards
describe the lamina propria of the mucosa
layer of loose CT that houses glands, blood vessels, immune cells
what type of muscle is in the muscularis mucosa of the mucosa layer
smooth muscle involved in contraction of mucosa
describe submucosa
layer of dense irregular CT; houses mucus glands in the esophagus and duodenum; blood vessels, lymph vessels and nerve plexi are found in the submucosa
what is the enteric plexus that controls secretion in the mucosa and submucosa
meissner’s (submucosal) plexus
what controls the contraction of the muscularis mucosa
meissner’s plexus
what is the enteric plexus that controls the churning and peristaltic action of the external muscle layer (located between 2 muscle layers)
auerbachs/myenteric plexus
where does the initial digestion of proteins and lipids occur
cardiac, fund, and pyloric stomach
where does terminal digestion of proteins, lipids and carbs occur as well as digestion of RNA/DNA
duodenum, jejunum and ileum
where does absorption of products of digestion into blood vessels or lacteals occur
duodenum, jejunum and ileum
where does absorption of water and production of dry fecal mass occur
colon/rectum
what is the main gland that secretes amylase
parotid salivary gland
what mainly secretes the lipase in the oral cavity
Von Ebners gland
describe the epithelium of the esophagus
non-keratinized stratified squamous
what provides lubrication of the esophagus
scattered submucosal mucous glands
what is the viscous pass that the stomach transforms food bolus into
chyme
what is the function of stomach
digestion of carbs, proteins and lipids
where are the mucous neck cells found
in the neck region of the fundic gland
what do parietal cells secrete
intrinsic factor
what does intrinsic factor do
binds vitamin B12
where is the B12/intrinsic factor complex absorbed
in the ileum
what is the most common cause of vitamin B12 deficiency
lack of intrinsic factor
what does a deficiency of intrinsic factor lead to
pernicious anemia
what are the key features of duodenum
villi, brunners glands, goblet cells
whats the diagnostic feature for the duodenum
Brunner’s glands
what is the diagnostic feature for jejunum
large plicae circularis
what is diagnostic feature for ileum
payer’s patches
what are transverse folds with a core of submocusa
plicae circularis
what are projections with core of lamina propria
villi
what are the cell surface projections with core of action filament
microvilli
what is the main purpose for plicae circulares, villi and microvilli
increase surface area
what are specialized cells located in the epithelium that covers lymphatic nodules in the lamina propria
M cells
what is the primary function of paneth cells
maintain mucosal innate immunity by secreting antimicrobial substances
what are columnar epithelial cells that produce disaccharides, are involved in absorption, and have an enzyme on the apical brush border that is important for carb digestion (produce enteropeptidase)
enterocytes
what are Brunner’s glands responsible for producing
formation of bicarbonate and mucous
what is the action and site of secretion of gastrin
secreted by stomach; gastric acid secretion
what is the site of secretion and action of ghrelin
secreted by stomach; stimulates appetite and inhibits lipid metabolism
what is the site of secretion and action of gastric inhibitory polypeptide
secreted by small intestine; inhibits gastric acid secretion and stimulates insulin release
what is the site of secretion and action of CCK
secreted by small intestine; stimulates secretion of pancreatic enzymes, bicarbonate release and contraction of gallbladder
what is the site of secretion and action of secretin
secreted by duodenum; increase bicarbonate and water secretion from pancreas; inhibits gastric acid secretion
what enhances the release of insulin by pancreatic beta cells and stimulates bicarbonate secretion by pancreas
secretin
what is the site of secretion and action of motilin
secreted by small intestine; increase gastric and intestinal motility
what is the site of secretion and action of pancreatic polypeptide
secreted by pancreas; opposes CCK (relaxes gall bladder and inhibits pancreatic secretions)
what is the site of secretion and action of somatostatin
secreted by GI tract; inhibits release of GI hormones
what do cells of intercalated ducts secrete
bicarbonate and water
where is trypsinogen converted to trypsin and by what
enterokinase in the duodenum
what is a complex fluid containing electrolytes and organic molecules including bile acids, cholesterol and bilirubin
bile
what are the 2 main functions of bile
emulsify fats and solubilize them; excretion of cholesterol and bilirubin in feces
where does Crohn’s disease typically occur
ileum
where does ulcerative colitis occur
colon./rectum
what are the symptoms of ulcerative colitis
abdominal pain, anemia, bloody stool, fever, fatigue
what is the treatment for ulcerative colitis
corticosteroids and 5-aminosalicylates
