Fiser Chapter 30. STOMACH Flashcards
Stomach transit time
3-4 hours
Where in stomach does peristalsis occur?
Just antrum (distal stomach)
What sympathetic fibers does gastroduodenal pain get sensed?
T5-10
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
Chief cells
Pepsinogen (1st enzyme in proteolysis)
Parietal cells
H+ and IF
What causes H+ release from parietal cells?
Ach (vagus)
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+)?
Somatotatin
Prostaglandins (PGE1)
Secretin
CCK
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
in duodenum
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
Dieulafoy’s ulcer
vascular malformation that can bleed