从医学角度看,肠-大脑轴和大脑微生物群的相互作用

The gastrointestinal tract, responsible for the digestion and absorption of nutrients, is safeguarded by the intestinal barrier, which consists of secretory, physical, and immune components. At the forefront is the secretory barrier, composed of essential elements such as mucus, gut microbiota, and defense proteins. They collaborate to break down food particles, facilitate nutrient absorption, and maintain optimal gut health. These secretory components ensure the smooth functioning of the...

Digestion begins with a cephalic phase that prepares the digestive system to receive food. When our brain processes visual or olfactory information about food, it triggers impulses in the cranial nerves innervating the salivary glands and stomach to prepare for food.

Although digestion of proteins, carbohydrates, and lipids may begin in the stomach, it is completed in the intestine. The absorption of nutrients, water, and electrolytes from food and drink also occurs in the intestine. The intestines can be divided into two structurally distinct organs—the small and large intestines.
Small Intestines
The small intestine is an ~7 meter-long tube with an inner diameter of just 2.5 cm. Since most nutrients are absorbed here, the inner lining of the...

Irritable Bowel Syndrome (IBS) is characterized by functional disturbances in the gastrointestinal system, presenting a cluster of symptoms without evident structural or biochemical abnormalities. It primarily affects the large intestine and may cause abdominal pain, bloating, excessive gas, diarrhea, constipation, or both.
IBS is a chronic condition that can persist over a long period or recur frequently.
The pathogenesis of IBS involves a complex interplay of the following factors:
Altered...

The human body contains a monogastric digestive system. In a monogastric digestive system, the stomach only contains one chamber in which it digests food. Several other animal species also have monogastric digestive systems, including pigs, horses, dogs, and birds. This chapter, however, focuses on the human digestive system.

Overview