GI Pathophysiology 1- Hideyo Flashcards
The function of the GI system includes
ingestion, fragmentation, digestion, & absorption
The following aids in digestion through secretion of enzymes:
salivary glands, liver (bile), gall bladder (stores & releases bile), & pancreas (secretes digestive enzymes trypsin, sodium bicarbonate, & insulin)
Fragmentation is the process of
chewing in which food is broken down into smaller particles
The GI system provides
nutrients, water & electrolytes to the body
Describe the anatomy of the GI tract.
lumen, epithelium, submucosa, muscularis externa/tunica muscularis
has longitudinal & circular muscles
The function of the esophagus and anus includes
protective
non-secretory, non-absorptive
The function of the stomach is
secretory
The function of the intestine is
absorptive
Describe the innervation of the esophagus.
innervated by glossopharyngeal and vagus nerve
The lower esophageal sphincter constricts at
30 mmHg
Describe the two types of glands in the stomach
Oxyntic (gastric) glands- includes surface & neck cells, parietal cells, & chief (peptic) cells
Pyloric glands- surface and neck cells, gastric cells
Describe what gastric surface and neck cells secrete.
mucus
Describe what parietal (oxyntic) cells secrete.
HCl
intrinsic factor- required for absorption of vitamin B12
Describe what chief (peptic) cells secrete
pepsinogen
Describe what pyloric surface and neck cells secrete.
mucus
Describe what gastric cells secrete
gastrin
The mechanism of gastric acid secretion is via
parietal cells in which Co2+H2O use carbonic anhydrase to produce HCO3- and H+
H+ is used in the ATPase pump in exchange for K+ coming into the cell
when chloride and hydrogen combine we get hydrochloric acid
Regulation of HCl secretion is thorugh
positive feedback: cephalic phase, gastric phase, & intestine phase
negative feedback: H+ mediate (inhibits gastrin secretion)
The cephalic phase is mediated by
the vagus nerve
gastrin release, histamine release and the vagus nerve stimulates the ATPase pump to increase production of HCl
The gastric phase is initiated by
chemical stretch of stomach, alcohol, and caffeine
to release gastrin and ultimately increases production of HCl
______ inhibits gastrin secretion (negative feedback system).
somatostatin
Common causes of gastric ulcer include
excess NSAID or infection by H. pylori
Therapy for gastric ulcer includes
antibiotics (H. pylori) & PPIs
surgical resection of vagus nerve to decrease acid production
