mucosal barrier & peptic ulcer 1. gastric muosal barrier the gastric mucosal barrier is the...
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MUCOSAL
BARRIER &
PEPTIC ULCER
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GASTRIC MUOSAL BARRIER
The gastric mucosal barrier is the property
of the stomach that allows it to contain acid
If the barrier is broken, then the acid
diffuses back into the mucosa and damage the
stomach wall
The gastric mucosal barrier is made up of 3
components:
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GASTRIC MUCOSAL BARRIER
a) Compact epithelial cell lining
with tight junctions
b) Gastric mucus covering (gel like
coating)
c) Bicarbonate ions, secreted by the
surface epithelial cells. The
bicarbonate ions act to neutralize
harsh acids
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GASTRIC MUCOSAL BARRIER
• The gastric mucosal barrier is the
property of the stomach that allows it to
contain acid.
• The barrier consists of three protective
components. These provide the
additional resistance for the mucosal
surface of the stomach. to neutralize
harsh acids.
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THREE COMPONENTS
The three components include: • a) A compact epithelial cell lining. Cells in the
epithelium of the stomach are bound by tight junctions that repel harsh fluids that may injure the stomach lining.
• b) A special mucus covering, derived from mucus secreted by surface epithelial cells and Foveolar cells. This insoluble mucus forms a protective gel-like coating over the entire surface of the gastric mucosa. The mucus protects the gastric mucosa from auto digestion by e.g. pepsin and from erosion by acids and other caustic materials that are ingested.
• c) Bicarbonate ions, secreted by the surface epithelial cells. The bicarbonate ions act as buffers
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MUCUS
Mucus is secreted by mucus cells
Present allover the GIT
Acts as a protectant and lubricant of wall of gut
Mucus is a viscous gel which contains mucin,
phospholipids, electrolytes (mainly HCO3) and water
Separates the epithelial cells from acid of stomach
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CONT’D
This maintains the Ph of epithelial cells
alkaline despite gastric acid
Mucus is strongly resistant to digestion by
gastric enzymes
Has buffering properties (neutralize acid)
Helps in propulsive movement by lubrication
Easy slippage of food
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PEPTIC ULCER
Ulcer :- An Ulcer is a discontinuity or
break in a bodily membrane, or breach in
the epithelium
Ulcer may occur anywhere in the body
When it occurs in stomach its gastric
ulcer
In duodenum its duodenal ulcer
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CONT’D
Ulcer occurring in either of these two
sites is called peptic ulcer
Its also known as acid peptic disease
(APD)
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PATHO PHYSIOLOGY OF PEPTIC ULCER
Defect in the mucosal barrier
Hyper secretion of acid
Helicobacter bacterial infection
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DEFECT IN THE MUCOSAL BARRIER
If the secretion of mucus is impaired
Or bicarbonate production is
impaired
Such damage is caused by drugs like
asprin, NSAID
Chronic stress conditions (stress
ulcer)
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HYPER SECRETION OF ACID
Chronic anxiety
Common in people with busy life style (Type A
personality)
Hurry, worry, curry
Intake of spicy food – leads to hyper chlorhydria
Conditions with hyper chlorhydria
(Zollinger Ellison syndrome ) gastrin secreting
tumor
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H.PYLORI INFECTION
Major cause of peptic ulcer
This bacterial infection causes Damage
to the mucosal barrier
Increase in gastrin secretion from G
cells
Reduce somatostatin from D cells
Initially causes gastritis which later on
leads to peptic ulcer
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CONTD …..
Helicobacter pylori, previously Campylobacter
pylori, is a Gram-negative, micro aerophilic
bacterium found in the stomach, and may be
present in other parts of the body, such as the
eye.
It was identified in 1982 by Australian
scientists Barry Marshall and Robin
Warren, who found that it was present in a
person with chronic gastritis and gastric ulcers,
conditions not previously believed to have a
microbial cause.
It is also linked to the development of
duodenal ulcers and stomach cancer. However,
over 80% of individuals infected with the
bacterium are asymptomatic and it may play an
important role in the natural stomach ecology.
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CONTD…..
More than 50% of the world's population harbor
H. pylori in their upper gastrointestinal tract.
Infection is more prevalent in developing
countries, and incidence is decreasing in Western
countries.
H. pylori's helical shape (from which the genus
name is derived)(Screw like, spiral) is thought to
have evolved to penetrate the mucoid lining of the
stomach.
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SIGNS & SYMPTOMS OF H. PYLORI INFECTION
Up to 85% of people infected with H. pylori never
experience symptoms or complications.
Acute infection may appear as an
acute gastritis with abdominal pain (stomach ache)
or nausea.
Where this develops into chronic gastritis, the symptoms,
if present, are often those of non-ulcer dyspepsia: • stomach pains• Nausea• Bloating• Belching• sometimes vomiting or black stool.
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Individuals infected with H. pylori have a 10 to 20% lifetime
risk of developing peptic ulcers and a 1 to 2% risk of
acquiring stomach cancer.
Inflammation of the pyloric antrum is more likely to lead
to duodenal ulcers, while inflammation of the corpus (body of
the stomach) is more likely to lead to gastric ulcers and
gastric carcinoma.
H. pylori possibly plays a role only in the first stage that
leads to common chronic inflammation, but not in further
stages leading to carcinogenesis.
A meta-analysis conducted in 2009 concluded the eradication
of H. pylori reduces gastric cancer risk in previously infected
individuals, suggesting the continued presence of H.
pylori constitutes a relative risk factor of 65% for gastric
cancers; in terms of absolute risk, the increase was from 1.1%
to 1.7%.
H. pylori has also been associated with colorectal polyps
and colorectal cancer.
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ADAPTATION TO THE STOMACH’S ACIDIC ENVIRONMENT
To avoid the acidic environment of the interior of the
stomach (lumen), H. pylori uses its flagella to burrow into
the mucus lining of the stomach to reach the epithelial
cells underneath, where the pH is more neutral.
H. pylori is able to sense the pH gradient in the mucus and
move towards the less acidic region (chemotaxis).
This also keeps the bacteria from being swept away into the
lumen with the bacteria’s mucus environment, which is
constantly moving from its site of creation at the epithelium
to its dissolution at the lumen interface.
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CONTD…..H. pylori is found in the mucus, on the inner surface of the
epithelium, and occasionally inside the epithelial cells
themselves.
It adheres to the epithelial cells by producing adhesions,
which bind to lipids and carbohydrates in the epithelial cell
membrane.
One such adhesion, BabA, binds to the Lewis b
antigen displayed on the surface of stomach epithelial cells.
Another such adhesion, SabA, binds to increased levels
of sialyl-Lewis x antigen expressed on gastric mucosa.
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CONTD…..
In addition to using chemotaxis to avoid areas of low
pH, H. pylori also neutralizes the acid in its
environment by producing large amounts of urease,
which breaks down the urea present in the stomach
to carbon dioxide and ammonia.
The ammonia, which is basic, then neutralizes
stomach acid.
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SYMPTOMS OF PEPTIC ULCER
Upper abdominal pain
Pain usually by empty stomach
relieved by food or antacid
Vomiting
Blood vomiting and perforation in
severe cases
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FACTORS THAT STIMULATE ACID SECRETION
Acetylcholine
Gastrin
Histamine
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TREATMENT
Anti histamines
Anticholinergic drugs
Proton pump blockers
Sucralfate
Gastrin blockers
Antacids
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NON SPECIFIC TREATMENT
Avoid stress
Adequate sleep
Regulation of diet
Avoid spicy foods, alcohol
Withdrawal of drugs like aspirin,
NSAIDS
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SURGICAL TREATMENT
Vagotomy
Gastrectomy
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FACTORS THAT CAN DAMAGE THE BARRIER
Bacterial Infection by
Helicobacter pylori
-Alcohol
-Aspirin
-NSAID
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