The Stomach building

Structure of the stomach

The stomach is located in the upper part of the abdominal cavity - most of it lies to the left of the midline of the body and only a small part - to the right (Figure 1). The shape, volume, size, position of the stomach are variable: they depend on the constitution, the filling of gases, food, the tone of the musculature of the stomach, the nervous and hormonal effects, as well as the size and position of neighboring organs. The average capacity of the stomach is 1-3 liters. The stomach consists of the following parts: 1) the cardiac part, adjacent to the place of confluence in the stomach of the esophagus; 2) the bottom, also called the vault; 3) the body of the stomach; 4) pyloric part, consisting of a vestibule and a pyloric canal, ending with a gatekeeper (Figure 2). The latter reports the lumen of the stomach with the duodenum.

topography of the stomach
Fig. 1. Topography of the stomach: 1 - stomach; 2 - pancreas; 3 - transverse colon; 4 - duodenum; 5 - gall bladder ; 6 - common bile duct; 7 - liver ; 8 - esophagus .
structure of the stomach
Fig. 2. Structure of the stomach (scheme): 1 - cardia; 2-bottom (arch); 3 - body; 4 - vestibule of the gatekeeper; 5 - the gatekeeper; 6 - angled notch.

There are small curvatures of the stomach, facing right and up, and a large, turned to the left and down. The wall of the stomach consists of three membranes: serous, muscular and mucous. The external serous membrane is part of the peritoneum, the leaflets of which pass from neighboring organs. Under it there is a thin layer of connective tissue - a subserous layer, in which lie the blood and lymphatic vessels and the plexus. In places of the transition of the serous membrane to adjacent organs, ligaments are formed, supporting the stomach in a certain position.

The muscular membrane of the stomach consists of three layers of smooth muscles. The outer layer is formed by longitudinal fibers, the middle layer is circular and the inner layer is oblique; the middle layer thickens at the gatekeeper, forming a pommel (sphincter) pylorus. Between the muscle layers is the intermuscular neural plexus (Auerbach).

The mucous membrane of the stomach loosely associated with the muscular submucosa and forms folds having a diverse direction. In the submucosal layer lie the plexus of the blood and lymphatic vessels and the submucous nerve plexus (Meisner).

The mucous membrane of the stomach is covered with a peculiar cylindrical epithelium . It opens millions of excretory ducts of specific tubular glands, which contain four types of cells: major, additional, overlaying and intermediate. The main cells secrete pepsinogen, which turns into an acidic medium into pepsin , additional and intermediate - mucin, the covering cells - hydrochloric acid . Blood supply to the stomach is carried out by the right and left gastric and right and left gastro-omental arteries. The veins follow the course of the arteries and flow into the portal vein. Excretory lymph vessels are mainly directed to the gastric lymph nodes located near the large and small curvature of the stomach.

The stomach is innervated by the branches of the celiac plexus and vagus nerves.

It is now generally accepted that the secretory process is regulated by the nervous and humoral-hormonal mechanisms. The nervous mechanism includes all the links of the nervous system - from the cortex of the brain to the peripheral nerve endings.

Hormonal influence is exerted by hormones of the gastrointestinal tract (gastrin, enterogastrin, etc.) and endocrine glands (pituitary gland, adrenal glands). Humoral regulation of the secretory function of the stomach is carried out by sucked up extractives, as well as by the products of the breakdown of proteins.

The food that enters the stomach undergoes further digestion, which begins in the oral cavity ( carbohydrates ).

The stomach has not only a secretory, but also motor (motor), absorption and excretory functions. In the pyloric part of the stomach, gastromucoprotein is released (see Factors factors), which plays an important role in the process of hematopoiesis (see).

lymphatic and blood vessels of the stomach
Fig. 1. Lymphatic and blood vessels of the stomach (front view): 1 and 29 - lymphatic vessels and nodes; 2 and 31 are v. gastro - epiplolca dext. et sin .; 3 and 30 - a. gastro - epiplolca dext. et sin .; 4 - omentum majus; 5 and 26 - v. gastrica dext. et sin .; 6-aorta abdominalis; 7 - v. lienalis; S - lobus dext. hepatis; 9 - ductus choledochus; 10 and 25 - a. lienalis; 11 - a. gastro-duodenalis; 12 - a. gastrica dext .; 13 - v. portae; 14 - vasa cystica; 15 - ductus cysticus; 16 - ductus hepaticus; 17 - a. hepatica propria; 18 - v. cava inf .; 19 - a. hepatica communis; 20 - a. phrenica; 21 - truncus coellacus; 22 - a. gastrica sin .; 23 and 24 are n. vagus dext. et sin .; 27 - pancreas; 28 - lien.