The stomach is an important organ of the body for digestion, with motor and secretory functions. The stomach has the functions of holding, grinding and transporting to help transport nutrients to the intestines. In addition the stomach secretes gastric acid, histamine and other important components that help in the digestion and breakdown of food.
1. Motility of the stomach: This includes the functions of accommodation, grinding and transportation. When food enters the stomach, the fundus and body of the stomach tend to produce accommodative diastole to receive the food.
2. Gastric secretion: The secretion of gastric juice is artificially divided into three phases, namely, the vagal phase (cephalic phase), the gastric phase and the intestinal phase. The cephalic phase involves the downward transmission of excitatory signals to the stomach in response to food stimulation, causing the secretion of gastric acid, pepsin, and mucus by mural, principal, and mucus cells. It also excites G cells and others, secreting gastrin, histamine.
Gastrin secreted by G cells plays a dominant role in gastric acid secretion in the gastric phase, and gastrin release is inhibited when pH<2.5 in the sinusoids and ceases at pH<1.2. The intestinal phase refers to the stimulation of the duodenum and proximal jejunum to secrete enterogastrin after food enters the small intestine leading to gastric juice secretion.
In conclusion, the stomach is an important organ for human digestion. After being stimulated by food, it excites the vagus nerve and regulates gastric acid secretion to help food digest and break down nutrients well in the body.