Flashcards in Fiser Chapter 30. STOMACH Deck (115)
Stomach transit time
Where in stomach does peristalsis occur?
Just antrum (distal stomach)
What sympathetic fibers does gastroduodenal pain get sensed?
Blood supply of stomach
Celiac: left gastric, CHA, splenic (L gastroepiploic and short gastrics are branches of splenic)
Greater curvature: R and L gastroepiploics, short gastrics. (R gastroepiploic is a branch of GDA)
Lesser curvature: R and L gastrics, R is branch off CHA
Stomach mucosa hitso
Simple columnar epithelium
Cardia glands versus fundus and body glands
Cardia: mucus secreting
Fundus and body glands:
Chief cells pepsinogen
Parietal cells H+ and IF
Pepsinogen (1st enzyme in proteolysis)
H+ and IF
What causes H+ release from parietal cells?
Gastrin (G cells in antrum)
Histamine (from mast cells)
Phosphorylase kinase and protein kinase A
Achetylcholine and gastrin MoA to increase H+ release
Activates phospholipase (PIP) --> DAG + IP3 to increase calcium -> calcium-calmodulin activated phosphorylase kinase -> increased H+ relaease
Histamine MoA to increase H+ release
Histamine activates adenylate cyclase -> cAMP -> activates protein kinase A -> increased H+ release
Phosphorylase kinase and proteine kinase A MoA to increase H+ release
They phosphorylate H+/K+ ATPase to increase H+ secretion and K+ absorption
How does omeprazole work?
Blocks H+/K+ ATPase in parietal cell membrane (the final pathway for H+ release)
What are inhibitors of parietal cells (which release H+)?
What does intrinsic factor do?
Binds B12, and then the complex is reabsorbed in the TI
Fundus and body glands versus antrum and pylorus glands
Fundus and body: chief cells and parietal cells with pepsinogen and H+ and IF release
Antrum and pylorus: G cells (release gastrin in antrum) and mucus and HCO3- secreting glands; and D cells (secrete somatostatin)
Why is an antrectomy helpful for ulcer disease?
G cells release gastrin (taken out)
What inhibits and stimulates G cells
G cells release gastrin
Inhibited by H+ in duodenum
Stimulated by amino acids and acetylcholine
What do D cells do?
Secrete somatostatin, which inhibits gastrin and H+ release
What do Brunner's glands do?
Secrete alkaline mucus
Antral and duodenal acidification causes what?
Somatostatin, CCK, and secretin release
MCC rapid and delayed gastric emptying
Rapid: previous surgery, ulcers
Delayed: DM, opiates, anticholinergics, hypothyroid
Trichobezoars and phytobezoars
Trychobezoars: Hair, hard to pull out, EGD generally inadequate and likely need gastrostomy and removal
Phytobezoars: Fiber, often in diabetics with poor gastric emptying, tx with enzymes, EGD and diet changes
vascular malformation that can bleed
Mucous cell hyperplasia, increased rugal folds
Nausea without vomiting, severe pains
Gastric volvulus, usually organoaxial
Associated with type 2 (paraesophageal) hernia
Tx: Reduction and Nissen
Hematemesis following severe retching
EGD with hemo-clips; Tear is usually on lesser curvature near GEJ
Bleeding often stops spontaneously, if continued bleeding may need gastrostomy and vessel oversewing
Truncal and proximal vagotomies
Both increase liquid emptying by removing vagally mediated receptive relaxation, causing increased gastric pressure that accelerates fluid emptying
Truncal (at level of esophagus): decreases solid emptying; add pyloroplasty to increase solid emptying
Proximal (high selective, divides individual fibers, preserves "crow's foot"): Normal emptying of solids
Truncal vagotomy effects
decreased solid emptying (and increased liquid emptying like all vagotomies); decreases acid output by 90%, increases gastrin and gastrin cell hyperplasia; decreases exocrine pancreas function and postprandial bile flow; increases gallbladder volumes, and decreases release of vagally mediated hormons; diarrhea in 40% (most common problem after vagotomy) due to sustained MMCs forcing bile acids into colon