杆菌及其在胃癌中的作用

Helicobacter pylori, a resilient gram-negative bacterium, can thrive in the stomach's harsh, acidic environment. Infection with H. pylori leads to a cascade of events within the stomach lining. One of the critical disruptions caused by this bacterium is the interference with somatostatin production, a hormone responsible for regulating acid secretion. This interference tips the balance, escalating acid secretion and diminishing bicarbonate levels. This imbalance compromises the defensive...

Peptic ulcers are sores on the stomach's inner lining and the upper small intestine, which are the result of disruptions in the mucosal layer that houses parietal cells which produce gastric acid, and chief cells which secrete pepsinogen.
In the antrum region, G cells secrete the gastrin hormone that binds to gastrin-cholecystokinin-B (CCK2) receptors on parietal and enterochromaffin-like (ECL) cells in the fundic glands. Simultaneously, the vagus nerve releases acetylcholine, which binds...

Peptic ulcer disease, commonly called PUD, represents a multifaceted condition characterized by disruptions in the lining of the gastrointestinal (GI)  tract. Central to the protection of the gastrointestinal lining is the mucosal-bicarbonate barrier. This physiological defense mechanism is a formidable shield against the corrosive effects of gastric acid and pepsin secretion in the stomach. Its role is pivotal in maintaining the structural integrity of the stomach's inner lining.

Gastritis is marked by disruption of the mucosal barrier that usually protects the stomach tissue from digestive juices and manifests in acute and chronic forms.
In acute gastritis, the gastric mucosa becomes swollen and red and undergoes superficial erosion. Superficial ulceration may lead to bleeding.
In chronic gastritis, persistent or repeated insults lead to chronic inflammatory changes and, eventually, thinning or atrophy of the gastric tissue.
Gastritis can stem from various causes, each...

Peptic Ulcer Disease (PUD) is characterized by mucosal excavation in the esophagus, stomach, pylorus, or duodenum. It can manifest as acute or chronic based on the extent and duration of mucosal involvement.
An acute ulcer, marked by superficial erosion and minimal inflammation, swiftly resolves upon identifying and addressing the underlying cause. In contrast, a chronic ulcer persists, potentially eroding through the muscular wall and forming fibrous tissue.
Peptic ulcers can also be...

The gastric glands contain parietal cells that secrete hydrochloric acid (HCl) for digestion. The cells secrete HCl because it is highly corrosive and essential for breaking down food. To achieve this, they secrete hydrogen and chloride ions into the lumen of the gastric glands, which combine to form HCl.
Within parietal cells, carbonic acid is first formed through the reaction of water and carbon dioxide. The dissociation of carbonic acid releases bicarbonate and hydrogen ions. The bicarbonate...