GI - 1 Flashcards
How do opioids cause constipation
They inhibit gut neurotransmission, motility, and secretion
Gut enterochromaffin cells (EC) in stomach release ______
histamine: stimulates gastric acid secretion
EC cells in the small intestine secrete ______
Serotonin: Increases gastric motility
failure of the lower esophageal sphincter to relax
achalasia
main cause of esophageal obstruction
Mechanical stenosis from inflammation such as chronic GERD
esophageal squamous cell carcinoma is associated with ____
cigarette smoking and alcohol consumption
Squamous cell carcinoma occurs most often in the ____esophagus
mid
Adenocarcinoma originates in the _____
distal third of the esophagus
Adenocarcinoma is associated with _____
Barrett esophagus
Change in esophageal epithelium from stratified squamous epithelium to simple columnar epithelium
Barrett esophagus
what causes GERD
Increased laxity of LES (b-adrenergic agonists, calcium channel antagonists, hiatal hernia)
Increased abdominal pressure (obesity, pregnancy)
cells that secret gastric acid
parietal cells
Proton pump
H+/K+ - ATPase
moves hydrogen ions into stomach lumen in exchange for potassium ions
Normal stomach pH
2.0
cells that secrete intrinsic factor
parietal cells that take B12 via receptors in ileum
cholecystokinin (CKK) is secreted in the ____ and signals ____ and circulates to the _____
Small intestine
fat digestion products
gall bladder
Glucagon-like peptide 1 (GLP-1) is secreted from the _____ and circulates to _____ to decrease _____ and the _____ to promote _____
ileum stomach motility pancreas insulin secretion
hubs of gut immune activity
Gut-associated lymphoid tissue (GALT)
peyers patches
particularly numerous in ileum
contains majority of gut microbiota
colon
phases of gastric acid secretion
- cephalic
- gastric
- intestinal
vagal acetylcholine release is most active during this phase
cephalic
60% of gastric acid secretion in this phase. Gastrin and histamine are secreted
gastric phase
stimulatory signals decrease, inhibitory signals increase (prostaglandins), acid secretion slows
Intestinal phase
role of prostaglandins
reduce acid secretion
increase mucus secretion
increase mucosal blood flow
NSAIDs block _____
prostaglandin production
increase risk for acid damage
