PEPTIC ULCER DISEASE Flashcards
(76 cards)
What is an ulcer?
A break through in the lining of the mucosa with appreciable depth at endoscopy.
What are erosions?
Superficial breaks in the mucosa that do not have perceptible depth.
What is a peptic ulcer?
Includes ulcers and erosions in the stomach and duodenum, involving mucosal integrity disruption and resulting in local defects due to active inflammation.
What does pepsin do?
Causes mucosal breaks regardless of the cause of the inciting agent.
What does the epithelial lining of the stomach contain?
Rugae or folds with microscopic gastric pits branching into 4 or 5 gastric glands.
What are gastric glands and what varies?
Gastric glands’ makeup varies with anatomical location.
What is the gastric cardia?
Comprises less than 5% of the gastric gland area and contains mucous and endocrine cells.
Where are most gastric glands found?
75% are found in oxyntic mucosa and contain mucous neck, parietal, chief, endocrine, enterochromaffin, and enterochromaffin-like (ECL) cells.
What are pyloric glands and where are they found?
Similar to the cardia, they contain mucous and endocrine cells, and are found in the antrum of the stomach.
Where are parietal (oxyntic) cells found?
In the neck or isthmus of the oxyntic gland.
What happens to parietal cells in the resting state?
They contain prominent cytoplasmic tubulovesicles and short microvilli along the apical surface; H+ K+-ATPase is expressed in the tubulovesicle membrane.
What happens to parietal cells in the stimulated state?
Microvilli in the canaliculi lengthen, and the tubulovesicle membrane moves to the apical portion, forming a dense network of long microvilli.
What is the pre-epithelial barrier in the gastroduodenal defense system?
It is the most superficial barrier, composed of a mucus-bicarbonate-phospholipid bilayer.
What does mucus in the stomach contain?
Mainly water (95%) and a mixture of phospholipids and glycoproteins (mucin).
What role does the mucus gel play in protection?
Impeding diffusion of ions (e.g., hydrogen ion) and molecules (e.g., pepsin).
What is the role of bicarbonate in gastric protection?
It forms a pH gradient from 1-2 at the gastric luminal surface to 6-7 along the epithelial surface, stabilizing clots in ulcers.
What are the components of the epithelial barrier in gastric protection?
Mucus production, ionic transporters for intracellular pH maintenance, and intracellular tight junctions.
What is the purpose of heat shock proteins in the stomach?
They prevent protein denaturation and protect cells from increased temperature, cytotoxic agents, and oxidative stress.
What is restitution in gastric epithelial defense?
The process by which gastric epithelial cells migrate to restore a damaged region if the pre-epithelial barrier is breached.
What conditions are necessary for restitution?
Uninterrupted blood flow and an alkaline pH in the surrounding environment.
Why are ICU patients prone to develop stress-related mucosal injuries?
Due to ischemia and reduced blood flow to the GI tract during states like hypotension and shock.
What is the subepithelial defense layer?
The deeper mucosal layer with a microvascular system supporting mucosal defense.
What does the subepithelial layer provide?
HCO3 for acid neutralization, micronutrient supply, oxygen, and removal of toxic by-products.
What local factors in the stomach promote blood flow?
Nitric oxide (NO), hydrogen sulfide, and prostacyclin, which cause vasodilation of the microcirculation.
