Filling, emptying and motility of the stomach

Stomach filling
After swallowing, the mushy morsel (bolus alimentarius) enters through the ostium cardiacum under the gastric bubble along the curvatura minor. In the next phase, the filling passes through the body of the stomach to the pars pylorica, where the contents gradually accumulate. During filling, the stomach first expands symmetrically towards the curvatura major et minor, in the final phase it predominates in the direction towards the curvatura major. When swallowing, the moment the bite reaches the upper part of the esophagus, the stomach muscles reflexively relax. After filling, the stomach wall adheres to the contents by peristaltic contraction.

Stomach emptying
Antrum pyloricum and canalis pyloricus mix the food by peristalsis, which is transformed into chyme by the action of enzymes and mechanical processing. With each peristaltic wave, a small portion of the mash passes into the duodenum. The functional partition between the stomach and the duodenum is not the sphincter pylori, but the end of the antrum pyloric , or sulcus intermedius.

Stomach mobility and changes in its shape
Stomach motility is influenced by two factors, namely:


 * nervous influence,
 * substance influence.

Nervous influence
Parasympathetic works under the influence of psychological stimuli (hunger, taste, smell...) or under the influence of reflexes ( contact of swallowed food with the stomach wall, expansion of the stomach wall).

Substance influence
Part of the endocrine cells in the pars pylorica and in the duodenum produces the hormone gastrin due to the contact of the mucous membrane with food, which passes into the blood vessels and via the blood acts to increase the motility of the stomach and increase the secretion of the glands of the fundus and body of the stomach. On the contrary, the reduction of motility for a short time is caused reflexively as the so-called enterogastric reflex. This is caused by an increase in pressure, a change in osmotic pressure and a change in pH in the duodenum. This reflex inhibits peristalsis, interrupting the delivery of contents to the duodenum. At the moment when the conditions in the duodenum and stomach are balanced, the reflex stops working and the process is repeated. Another way to reduce activity is the action of digestive tract hormones. Secretinit stimulates the activity of the gastric glands and GIP, on the contrary, inhibits it.

The cause of defects in the mechanisms of mobility can be an atypical form of the stomach.