Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types –  adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as  epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as  heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
The endothelial cells...

Peptic ulcers are erosive lesions of the gastric or duodenal lining, most commonly caused by Helicobacter pylori infection. This Gram-negative, helical bacterium has adapted to survive the stomach’s acidic environment by producing urease, which converts urea into ammonia and carbon dioxide. The ammonia neutralizes gastric acid in the bacterium’s immediate environment, allowing colonization of the gastric mucosa. H. pylori attaches to mucus-secreting epithelial cells, penetrates the mucus...

The pathophysiology of gastritis begins with the colonization of the stomach lining by Helicobacter pylori (H. pylori). This bacterium spreads mainly via the oral-oral route through saliva or shared utensils, and can also be transmitted in overcrowded or unhygienic environments through contaminated water, despite its brief survival outside the body.ColonizationOnce ingested, H. pylori enters the stomach and begins colonization by navigating through the mucus layer lining the stomach wall. It...

Peptic ulcer disease develops when protective mechanisms of the gastrointestinal mucosa are overwhelmed by harmful factors, leading to localized erosions in the stomach or proximal duodenum. The main causes are Helicobacter pylori infection and chronic use of nonsteroidal anti-inflammatory drugs (NSAIDs).Helicobacter pylori–Induced InjuryBacterial Adaptation and Colonization:H. pylori is a spiral, Gram-negative bacterium adapted to the acidic stomach. and transmitted through oral-oral or...