Flashcards in 9.2 Tum Tum Deck (25):
What do parietal cells secrete?
What do the secretions do?
HCl- make acid
Intrinsic Factor- needed for B12 absorbtion in small intestine
Stimulus- ACh, Gastrin, Histamine
What do chief cells secrete? Function?
Becomes pesin(protease, breaks down proteins)
Stimulus- ACh, gastrin
What do mucous cells secrete? Function?
Mucus- protect tissue
Stimulus- mechanical stretch of stomach, prostilglandins
What go G-cells secrete? Function?
Gastrin- Stimulates release of HCl by parietal cells
Stimulus- ACh, protein in stomach
What do enterochromaffin-like cells secrete? Function?
Histamine- Stimulates parietal cells (HCl)
Stimulus- ACh, gastrin
What do delta cells secrete? Function?
Somatostatin- Inhibits parietal, ECL, G-cells
= Less acid
Stimulus- Acid in stomach
What is the oxyntic mucosa?
Fundus – expanded lateral portion
contains mucous cells, chief cells, parietal cells, ECL cells
oxyntic = “sharp” reference to acid secretion
What is the pyloric region? What cell types?
Pyloric (antrum) region – funnel shaped, continuous with the small intestines through the pyloric sphincter
contains G-cells and D-cells
What regulates the motility of the stomach?
Volume: when full, motility and emptying is stimulated
Fluidity: when more broken down, chyme is easier to move and emptying will be stimulated
High levels of Fat, Acid, distension of small intestine will inhibit emptying until the small intestine can process more
Stress: inhibits motility and emptying via SNS
What is Barret's esophagus?
metaplasia of esophageal cells (simple squamous columnar) due to repeated acid injury, precancerous
Chronic reflux disease– Barret’s esophagus- metaplasia (simple squamous--> columnar cells)= precursor to cancer
What are the causes of peptic ulcer disease?
H.pylori infection damages stomach mucosa causing erosions and ulcers ranging from mm to cm.
burrows in mucosa, typically pyloric antrum (lowest acid region)
secretes of urea (converted to ammonium), proteases, cytotoxins, phopholipases by H. pylori
hypersecretion of HCl, decreased mucus production, reduced cellular repair
erosion of mucose, diffusion of HCl into stomach will, inflamamation and ulceration
abdominal pain between meals, when stomach is empty
irritated by stress, caffeine, smoking, NSAIDs (suppression of prostaglandin E2)
What are the most serious SA of PUD?
perforation: sudden excruciating abdominal pain, abdominal rigidity, vomiting blood
What are the morphological changes to the small intestine that increase surface area?
Plicae circulares – circular ridges in the mucosa and submucosa
Villi – finger-like projections of the mucosa
epithelial (“brush border” and goblet cells
Microvilli – tiny projections of the epithelial cell plasma membrane
In order, what are the sections of the small intestine?
What is the function of the duodenum?
chemical digestion: majority in the body occurs here, enzymes and bicarbonate from pancreas, bile from the liver, final step = brush border enzymes
Brunner’s glands: alkaline mucous secreting glands to neutralize acid entering from stomach
What is the function of the jejunum?
nutrient absorption: majority in the body occurs here
What is the function of the ileum?
last segment up to ileocecal valve
majority of Vitamin B12 absorption
return of bile salts to the liver via enterohepatic circulation
Peyer’s Patches: MALT (mucosa associated lymphatic tissue) in the submucosa
What is segmentation in the small intestine?
a series of ring-like contractions using circular muscle that mix and propel chyme in the small intestine
** Not propulsive, mixes chyme
Where do digestive (brush border enzymes come from)?
Bound to brush border
What are the functions of enterokinase, disachharidases, and amino peptidases?
Enterokinase: activates trypsin
Disaccharidases: breaks down disaccharides into monosaccharides
Aminopeptidases: breaks down peptides into amino acids
What is the function of enterogastornes? What are they?
Small intestine regulates the stomach with enterogastrones
CCK, Secretin: give small intestone time to process, helps lower acid
What enters gut cells via secondary transporters? By simple diffusion?
Fatty acids, hormones
What are some mechanism of diarrhea?
osmotic balance disrupted
inflammation, lack of absorption
secretion of mucus, fluid stimulated
excessive motility of intestines
What is celiac disease?
sprue, gluten sensitivity) – hypersensitivity reaction to gluten
unknown mechanism, autoimmune, inflammation, increase in T-cells
serum IgA antitissue transglutaminate (IgA TTG)
biopsy of duodenum or jejunem
gluten peptide: gliaden
damage to intestinal mucosa, destruction of villi, decreased surface area for absorption
impaired absorption of nutrients, vitamins, minerals, bile salts