2. Stomach Flashcards
Describe Stomach histology and cell secretions. Plus Pathways to acid secretion
Name 3 acid blocker drugs
Oxyntic/ Fundic Glands
- found in fundus, body
- Parietal Cells - HCL, IF
- Chief Cells - Pepsinogen
- G Cells - Gastrin
Pyloric glands (cardiac glands also)
- mostly mucous
- G Cells
Peptides - G Cells - Gastrin to Parietal Cells
Food - Vagus - Ach to Parietal Cells
Gastrin and Act to ECL cells
- ECL - Histamine - to Parietal Cells
Cimetidine, Famotidine - H2 Antihistamine
Omeprazole - H+ - K+ ATPase
4 Mechanisms of Gastric protection
- protection at normal state
Mucosal Blood supply
- remove waste, acid, support epithelial cells
Mucous Layer + Bicarbonate secretion
- prevent contact of acid/enzymes w epithelium
Zymogen form of Pepsinogen;
Intercellular tight junctions of epithelium
- prevent back diffusion of H+
VITAMIN of acute gastritis
Give Vascular
Give Drug
Give Metabolic
Vascular - PTH, blood vessels dilate, mucosa more friable; ISCHEMIA
Infection - H. Pylori
Toxin - alcohol, drugs (NSAIDs blokcing PGE2, I2); Cigarettes, radiation
Autoimmune
Metabolic - Uremia (increased ammonia decreases HCO3 secretion through inhibiting transport) - same mechanism as H. Pylori (urease secretion)
Idiopathic
Neoplasm
Trauma - intracranial injuries - vagal tone
Chronic Gastritis histology + Name 2 causes
Dysplasia, Intestinal Metaplasia - Carcinoma
Atrophy
Lymphocyte infiltrate + aggregates
H. Pylori infection
Autoimmune Gastritis
H. Pylori - Pathophysiology: 3 enzymes plus 2
- bacteria attacks all 3 protection mechanism!
Urease - Urea to ammonia - high ammonia inhibits bicarb secretion
Protease - mucous glycoprotein
Phospholipase - Epithelial cells
Bacterial Platelet Activating Factor - Thrombus
Attracts neutrophils - release myeloperoxidase
Triggers inflammation
H. Pylori diagnosis
Urea Breath Test
Serology, Histology, Culture (Gram NEG spirochete)
Autoimmune Gastritis pathology and Cx
Starting from what autoimmune targets and presentations and Cx
FDAP?
Autoimmune against Oxyntic Glands - hence atrophy at Gastric Body - Fundal atrophy
Parietal Cell destruction - Low H+, Gastrin feedback loop - Hyperplasia of G cells - Hypergastrinemia
Achlorhydria, Low Pepsinogen, Hypergastrin, Pernicious Anaemia
Cx: adenocarcinoma, pernicious anaemia, Carcinoid tumor (from ECL trophic effect from Gastrin)
Carcinoid syndrome, releases Serotonin 5HT: Flushing, Diarrhea, Ab cramping, Peripheral Edema
PUD morphology, 3 histological zones
Chronic mucosal ulceration
- sharply punched out CLEAN base; deep through muscularis mucosae
- Cancer ulcers bases are irregular and necrotic
- Zone of fibrinopurulent exudate, granulation tissue, scarring tissue
