Gastric Acid Disorders Patho

gastric pits

there are millions of these in the lining of the GI tract that lead to the gastric glands that produce gastric juice

g cells

cell type that secretes gastrin

parietal cells

cell type that secretes gastric acid

proton pump

hydrogen-potassium pump located on the surface of parietal cells

hydrogen

the parietal cell proton pump moves one of those ions OUT of the cell into the stomach lumen

potassium

the parietal cell proton pump moves one of these ions INTO the cell

concentration gradient

the parietal cell proton pump moves potassium and hydrogen ions against their…

chloride

this ion enters the parietal cell to form HCl with hydrogen

gastrin, acetylchloine, histamine

these 3 hormones stimulate acid secretion

h2

histamine receptor on the surface of parietal cells

g protein coupled

type of receptor that the h2 receptor is

h2 receptor

the cellular response of this receptor is translocation of proton pumps to the plasma membrane → dec pH of stomach lumen

h+ secretion

when the cellular response occurs from h2 receptor, this is the mechanism BY WHICH pH decreases

acid disorders

these result from an imbalance of aggressive/damaging (or potentially damaging) factors and mucosal defense/protective factors

mucosal barrier

maintaing the integrity of this in the gastric environment is the key to avoiding damage from acid

tight junctions

this feature between epithelial cells prevents HCl from leaking into underlying tissue

HCO3

component of mucosal barrier fluid (mucus) that neutralizes stomach acid

mucin

protein in mucus that helps it perform its functions

GERD

symptomatic condition or histologic change associated with retrograde movement of gastric contents to esophagus

PUD

gastritis, erosions, and ulcers of the GI tract that requires gastric acid for their formation

duodenum

more common site of peptic ulcers

lower esophageal sphincter

most commonly, GERD is caused by incompetency of this feature

pressure

when the LES in incompetent, this is reduced and when stomach pressure exceeds LES pressure the contents will come up

hiatal hernia

a risk factor for GERD where the stomach bulges up into the chest through the hiatus of the diaphragm

peppermint

a food that can often trigger GERD in sensitive patients

barretts esophagus

a sequelae of more severe GERD that involves metaplasia of stratified squamous cells into columnar and goblet cells

adenocarcinoma

barretts esophagus cellsare more likely to develop into this condition

PUD

injury to the mucosa of the stomach that can range from slight injury to severe ulceration and bleeding

helicobacter pylori

bacteria that is the most common cause of PUD

smoking

increases the risk of developing PUD

flagella

feature of h. pylori that help it move below the mucosal surface to coloize the gastric epithelium

mucous layer

h pylori can cause PUD by disrupting this layer, neutralizing pH, and releasing enzymes and toxins

urease

enzyme that converts urea to CO2 and ammonia, which neutralizes the acid and can injure/irritate the mucosa

gastric cancer

h pylori is also associated with this condition because it inhibits apoptosis of gastric pit cells and encourages chronic inflammation

cagA

toxin produced by h pylori that can degrade p53 proteins that normally suppress protein

de-gelling

this is required before the h pylori can move further and cause damage to gastric epithelium

endoscopy

gold standard for diagnosing h pylori infection

breath test

another method of detecting h pylori infection that is less invasive

co13 and co12 ratio

isotopes used to detect presence of h pylori in breath

neutrophils

NSAIDS can increase adherence of these to the vascular endothelium, causing more ROS damage

COX-1 and COX-2

NSAIDs inhibit these, which therefore also inhibit several beneficial prostaglandins

arachidonic acid cascade

NSAIDs inhibit prostaglandins that are produced in this process

corticosteroids

combination of this medication class with NSAIDs can make a patient more susceptible to PUD

stress ulcer prophylaxis

the use of medications to prevent peptic ulcers while a patient is in the hospital

no

do all patients need stress ulcer prophylaxis

epigastric pain

main symptom of PUD

stomach

ulcer type where pain is aggravated by food

duodenum

ulcer type where pain is relieved by food

alarm symptoms

present in patients with chronic PUD, can indicate need for emergency care

alarm symptoms

these include: bleeding (melena or hematemesis), perforation (Radiating pain to back), obstruction (vomiting, abdominal distention)