6 Questions
What is the role of urease in the survival of H. pylori in the stomach?
Urease converts urea into bicarbonate and ammonia, creating an acid-neutralizing cloud around H. pylori.
Why is the reaction of urea hydrolysis important for the diagnosis of H. pylori?
The reaction of urea hydrolysis produces detectable products like ammonia, which are identified in the breath test.
Describe the role of the immune system in response to H. pylori infection and its consequences.
The immune system sends white cells and killer T cells, which cannot easily reach H. pylori, leading to continued immune response and damage to stomach lining cells.
List the main factors involved in the virulence of H. pylori.
Cytotoxin associated proteins, LPS, flagellum, urease, and adhesin.
How does H. pylori escape the body's natural defense mechanisms?
H. pylori escapes by residing in the mucus lining of the stomach where the body's infection-fighting agents cannot easily reach.
What destructive process occurs due to the prolonged immune response to H. pylori?
Polymorphonuclear cells die and release superoxide radicals, damaging the stomach lining cells.
Study Notes
Urease and Acid Neutralization
- H.pylori uses the enzyme urease to convert urea into bicarbonate and ammonia, creating a cloud of acid-neutralizing chemicals around it.
- This protects the bacterium from stomach acid.
- Urea is abundant in the stomach, coming from saliva and gastric juices.
Defense Mechanism of H.pylori
Escape from Natural Defense
- The mucus lining of the stomach prevents the body's natural defenses from reaching H.pylori.
- The immune system responds to H.pylori infection by sending white cells, killer T cells, and other agents, but they cannot easily penetrate the stomach lining.
Immune System Response
- Infection-fighting agents persist and the immune response grows, leading to the death of polymorphonuclears.
- Dying polymorphonuclears release destructive compounds (superoxide radicals) that harm stomach lining cells.
Factors Involved in Virulence
- Cytotoxin-associated proteins are the main factor in virulence.
- Lipopolysaccharides (LPS) play a crucial role.
- Flagellum and urease are necessary for adhesion and inhabitation.
- Adhesin pathogenesis response is initiated.
Learn how H. pylori bacteria defend against stomach acid using the enzyme urease. Understand the reaction of urea hydrolysis and how it creates a protective cloud of acid-neutralizing chemicals.
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