Stomach anatomy, functioning and diseases
Image: “Stomach Pic for Food Poisoning Thingy” by Daniel X. O’Neil. License: (CC BY 2.0)
Macroscopic anatomy of the stomach
Location of the stomach
The stomach is in left upper abdomen in the Regio epigastrica and in the Region hypochondriac sinistra. While the location of most sections of the baggy muscle tube is very variable, there is orally and aborally two remain in position Sections: The stomach entrance (Kardia) fixed by the lower esophageal sphincter and the stomach jaw (pylorus), which passes into the retroperitoneal duodenum and is therefore immobile.
Outer shape of the stomach
A large and a small curvature can be distinguished on the stomach, whichParies anterior) from the back wall (Paries posterior): The concave curvatura minor with a kink (notch angularis) at the transition to the pylorus and the convex curvatura major between fundus and antrum pyloricum. In addition, the stomach can be divided into four sections:
- cardia(Cardia, pars cardiaca): Transition of the esophagus into the stomach, which is closed by a functional sphincter
- stomachdome (Fundus gastricus): The highest point of the stomach standing up, which is separated from the cardia by the cardiac incisura; Here is a collection of swallowed air, which is visible in the X-ray as a gastric bladder.
- gastric body(Corpus gastricus): Main section of the stomach from Fundus gastricus to Pars pylorica
- Pförtnerabschnitt (Pars pylorica): Transition of the wide antrum pyloricum into the narrow canal of the pyloricus with an end in the pylorus. This consists of thick ring musculature and thus forms the sphincter pylori muscle as a border to the duodenum.
Picture: “Illustration from Anatomy & Physiology, Connexions Web Site “from OpenStax College. License: CC BY-SA 3.0
The external shape of the stomach is very variable and depends on various factors such as filling state (empty: paries anterior and posterior lie against each other), posture, gastric motility and physique. This is the most common finding in X-ray examinations hook stomach (similar to the letter “J”), for tall, slender persons (asthenics) often Longstomach (narrow and elongated) and in small, stocky persons (Pyknikern) often Bull horn stomach (almost horizontal).
Vascular supply of the stomach
The stomach becomes arterial from the Truncus celiacus, the first unpaired branch of the abdominal aorta. This usually gives off three arteries: The Arteria hepatica communis, the Arteria gastrica sinistra and the Arteria splenica. The Arteria gastrica sinistra forms through the anastomosis with the Arteria gastrica dextra (from the hepatic artery, which originates from the common hepatic artery) vascular arcade at the Curvatura minor. At the Curvatura major anastomosieren Arteria gastroomentalis dextra (from the gastroduodenal artery, which in turn comes from the common hepatic artery) and Arteria gastroomentalis sinistra (from the artery splenica) and thus form another vascular arcade.
Furthermore, the artery splenica branches to supply the fundus (Arteries gastricae breves) and the stomach posterior wall (Arteria gastrica posterior).
Picture: “The Truncus celiacus and its branches.” By Henry Gray. License: (CC0 1.0)
The veins of the stomach run with the arteries of the same name and lead the blood into the portal vein system, whereby the Venae gastricae dextra et sinistra directly into the portal vein (vena portae) open, while the Vena gastroomentalis sinistra into the vena splenica and the Vena gastroomentalis dextra into the superior mesenteric vein.
Peritoneal conditions of the stomach
The stomach is lying intraperitoneally. From the curvatura minor pulls the Omentum minus (small mesh) as a peritoneal duplication to the liver. This comes from the Mesogastrium ventrale and settles in that Ligamentum hepatogastricum and the Ligamentum hepatoduodenal (contains the portal triad) break down. It depends on the Curvatura major Omentum greater (large network), which from the Mesogastrium dorsal emerges apron-like over the large and small intestine down. Furthermore, the following ligaments are part of the greater omentum:
- Ligament gastrophrenicum: between great curvature of the stomach and underside of the diaphragm
- Ligament gastrosplenicum: between the stomach and spleen, contains the arteria splenica with the arteria gastricae breves
- Ligamentum gastrocolicum: between great curvature and large intestine (transverse colon), contains the arteriae gastroomentales dextra and sinistra
Relationship of the stomach to the neighboring organs
With its location in the upper abdomen, the stomach has contact with various abdominal organs:
- liver(Facies hepatica): The left lobe of the liver covers the stomach on the right and ventrally.
- diaphragm(Facies phrenica): The fundus attaches to the left diaphragmatic dome, which separates the stomach from the pleural cavity.
- spleen(Facies splenica): The spleen is to be found in the left rear half of the stomach in the area of the fundus (Cave: Risk of injury in stomach operations!).
- pancreas(Facies pancreatica): Dorsal of the stomach pulls the pancreas tail. The bursa omentalis separates the be >Microscopic anatomy of the stomach
Structure of the stomach wall
Picture: “Intermediate magnification micrograph of normal gastric mucosa, i.e. inner most layer of the stomach. “by Nephron © 2010. License: (CC BY-SA 3.0)
The construction of the stomach wall corresponds to that of the entire gastrointestinal tract with its typical five layers: Tunica mucosa, Tela submucosa, Tunica muscularis, Tela subserosa and Tunica serosa. However, while the tunica muscularis in the rest of the trunk intestine from a longitudinal muscle layer (Stratum longitudinal) and a ring muscle layer (Stratum circulare), there is still a third innermost muscle layer of oblique fibers in the stomach (Fibrae obliquae) available.
The tunica mucosa consists of the Lamina epithelialis with single-layered high-prismatic epithelium (epithelium), which at the Ora serrata (Z-line) sharp against the multilayer squamous the esophagus is delimited from the Lamina propria with the gastric glands and out of the Lamina muscularis.
In the corpus gastricum are mucosal folds, the Plicae gastricae, to recognize which are particularly pronounced on the small curvature and elapse in gastric filling or expansion. Furthermore, there are gas fields on the mucosal surface (Area gastric) with stomach pits (Foveolae gastricae) into which the gastric glands open.
Picture: “Transition from esophageal to gastric mucosa: Ora serrata” by Jpogi. License: (CC0 1.0)
At the stomach entrance lie the wide-lobed, branched Kardiadrüsen (Glandulae cardiales), which mainly produce mucus. The pyloric (Glandulae pyloricae) of the Pars pylorica also form mucus. In addition, G cells are found here, which stimulate the parietal cells gastrin to produce. Those occupying most of the mucous membrane main glands (Glandulae gastricae propriae) are in fundus and corpus. They are Englumig, long, little branched and consist of the following cells:
- Main cells: basophilic (since much rough endoplasmic reticulum) and lying at the gland base, production of pepsinogen and lipase
- Receipt / parietal: eosinophilic (mitochondrial) and located in the middle of the gland, secretion of hydrochloric acid and intrinsic factor (necessary for vitamin B12-Resorption in terminal ileum)
- In addition to cells: found in the glandular neck, formation of bicarbonate and mucus
- Endocrine cells: located in the basal half, production of histamine
Picture: “Illustration from Anatomy & Physiology, Connexions Web site. “From OpenStax College. License: (CC BY-SA 3.0)
The protection of the stomach wall is ensured by a mucus coating, which contributes to the formation of the cardia, pylorus and main glands (secondary cells) and the cells of the surface epithelium.
Function of the stomach
The stomach has one reservoir function, that is, it temporarily stores the food before it enters the intestine in portions. This makes it possible to get along with a few large meals a day. After a gastrectomy Meals must be spread over many small portions a day. The already started in the oral cavity digestion is continued here with the digestive enzymes of the stomach: the inactive precursor pepsinogen is activated by contact with the gastric acid to pepsin, which splits protein compounds and so on Vorverdauung contributes to the proteins.
Another important task is the production of the gastric juice, from which one to three liters are made per day. It is mainly composed of hydrochloric acid and intrinsic factor (derived from parietal cells), mucus and enzymes. Due to the hydrochloric acid is the PH value of the gastric juice angry, whereby most bacteria (exception: Helicobacter pylori) are killed and thus infections of the intestine are prevented.
Diseases of the stomach
The functional dyspepsia (irritable stomach) is characterized by nausea and vomiting, a postprandial feeling of fullness and premature satiety, and a diffuse upper abdominal pain. To diagnose functional dyspepsia, the symptoms have to be one longer than three months present and the other not due to organic causes (diagnosis of exclusion) his. For this purpose, diagnostic measures such as gastroscopy, ultrasound and the acceptance of laboratory parameters should be carried out. It is a harmless condition that is often associated with mental health problems. A treatment can symptomatic respectively.
At a acute gastritis Mucosal bleeding occurs due to destruction of the mucosal barrier. Causes can be endogenous or exogenous. Among the exogenous Noxen count alcohol, drugs (Acetylsalicylic acid, cytostatics) and bacteria (Staphylococci, salmonella). Clinically, acute gastritis manifests itself in epigastric pressure pain, nausea and vomiting, and loss of appetite. A dreaded complication is the gastrointestinal bleeding at erosive gastritis As therapy comes primarily the transient nutritional delay and abstaining from alcohol and nicotine in question. For symptomatic treatment are suitable antacids (e.g., proton pump inhibitors) and antiemetics.
In contrast to acute gastritis, patients with one chronic gastritis usually symptom-free. Only a few patients may experience unspecific upper abdominal complaints. Chronic gastritis can be divided into the following forms:
- Type A: autoimmune gastritis. This form is limited to the cardia and corpus. There are antibodies against parietal cells and intrinsic factor. The increasing loss of parietal cells leads to a achlorhydria and the lack of intrinsic factor to a disturbed vitamin B12-Intake in the terminal ileum with sequence of one pernicious anemia. Some patients have another autoimmune disease. The risk of gastric carcinoma is significantly increased.
- Type B: Bacterial gastritis. In the antrum-localized type B gastritis, there is an infection of the gastric mucosa with the bacterium Helicobacter pylori in front. It shows an ascending spread in the corpus ventriculi, causing a decrease in the number of parietal cells with hypochlorhydria coming.
- Type C: Chemical gastritis. This type of gastritis is mainly caused by a bile reflux or NSAIDs, like ibuprofen or diclofenac.
To be diagnosed by means of gastroscopy biopsies taken from the gastric mucosa. In addition, you can invasively (Helicobacter urease test) and non-invasive (13 C-breath test) to colonize with Helicobacter pylori test. In type A gastritis auto-antibodies (against parietal cells and intrinsic factor) and a reduced vitamin B can be12-Find mirrors in the serum.
Picture: “Gastritis” by openi. License: (CC BY 2.0)
Therapeutically comes in the presence of symptoms, the treatment of these just in question. Furthermore, in type B gastritis with appropriate indication (e.g., peptic ulcer disease) one may Helicobacter pylori eradication by means of Triple therapy (Proton pump inhibitor + clarithromycin + amoxicillin or metronidazole). For a vitamin B12-Lack of autoimmune gastritis this can be substituted. In addition, due to the increased gastric carcinoma risk annual Control gastroscopies to recommend.
At the Gastric ulcer (stomach ulcer) there is a defect of the mucosa that reaches deep into the muscularis mucosae. It is mainly because of the small curvature and in antrum localized and can be due to various causes, the Degradation defensive (Protection by slime) and the Reinforcement of aggressive factors (Stomach acid) is in the foreground.
Picture: “gastric ulcer” by openi. License: (CC BY 2.0)
The majority of gastric ulcers is caused by colonization with Helicobacter pylori and thus results from chronic gastritis. However, the intake of nonsteroidal anti-inflammatory drugs (NSAIDs) and smoking by inhibiting the secretion of productive acting prostaglandins lead to an ulcer. Clinically, a gastric ulcer is often asymptomatic, In some patients, there is pain on the left paraumbilical, which may be food-independent or enhanced by food intake. However, the first symptoms usually appear when complications occur. These include in the first place Bleeding, perforation and penetration.
The diagnosis of an ulcer will be endoscopically provided that a tissue sample should be taken to exclude gastric carcinoma. In an infestation with Helicobacter pylori comes the Triple therapy (s.o.) in question. For therapy Helicobacter pylori-negative ulcers are Proton pump inhibitors the first choice in drug therapy. In addition, should be dispensed with harmful Noxen such as alcohol and nicotine. Surgical indications include unquenchable bleeding, free perforations, gastric outlet obstruction and carcinomas.
Image: “Gastric cancer in the advanced cityium (endoscopic image).” By Boreali. License: (CC0 1.0)
The Carcinoma ventriculi has its peak in incidence between the ages of 50 and 60 and a decreasing incidence. The most common is carcinoma in the area of small curvature and the Pars pylorica to find. The symptoms are Unspecified and range from pressure in the upper abdomen to nausea and performance kinking. Only in the advanced stage of the disease can it too Weight loss, iron deficiency anemia, vomiting and dysphagia come. For diagnosis, a gastroscopy with multiple biopsies is performed. Here it is important that the Diagnosis early as this can significantly improve the prognosis. For curative therapy only the operation with subtotal or total comes gastrectomy in question. At inoperability come palliative measures to improve the quality of life in question.
Picture: “gastric surgery.” By openi. License: (CC BY 2.0)
Examination of the stomach
|percussion||Through the gas bubble in the fundus a tympanitic knocking sound is produced (distinction to sonorous knocking sound of the lung and damped knocking sound of liver and spleen). The demarcation to the large intestine is difficult because the knocking sound of the transverse colon is similar to that of the stomach.|
|sonography||The alternating hyperechoic and echo-poor appearing layers of the intestinal wall are recognizable, however, the representation of the stomach in the ultrasound is often difficult or incomplete (problem: air).|
|Gastroscopy (gastroscopy)||The gastroscope is inserted through the mouth into the esophagus and advanced into the stomach. So the gastric mucosa can be assessed. It is also possible to take tissue samples and therapeutic interventions (for example, to stop bleeding).|
|MDP (gastrointestinal passage)||The implementation should be done in the early morning. For this purpose, the patient is orally first a radiopaque contrast agent (barium sulfate) and then an X-ray negative contrast agent (CO2). Under fluoroscopy, the gastric mucosa can now be assessed. The disadvantage of MDP is the radiation exposure.|
Popular exam questions to the stomach
The solutions are below the sources.
1. Which statement on the blood supply of the stomach applies?
- The small curvature is supplied by the arteries gastroomentales dextra et sinistra.
- The vena gastroomentalis sinistra empties into the superior mesenteric vein and the vena gastroomentalis dextra opens into the vena splenica.
- The fundus is supplied by the artery splenica.
- The vascular arcade at the great curvature consists of branches of the Arteria gastrica sinistra.
- The venous blood of the stomach is directed into the inferior vena cava.
2. Which statement concerning the peritoneal conditions of the stomach is not correct?
- The greater omentum arises from the dorsal mesogastrium.
- The ligament gastrosplenicum contains the arteriae gastricae breves.
- The omentum minus contains the ligamentum hepatogastricum.
- The gastrocolic ligament contains the posterior gastric artery.
- Among other things, the omentum minus arises from the mesogastrium ventrale.
3. The following statement about the histology of the stomach applies:
- The tunica muscularis consists of two layers, the stratum longitudinal and the stratum circulare.
- The columnar epithelium of the esophagus passes over the ora serrata into the multilayered squamous epithelium of the stomach.
- The major cells of the gastric glands are eosinophilic, located at the glandular base and produce enzymes such as pepsinogen and lipase.
- The parietal cells are also called parietal cells and are responsible, inter alia, for the secretion of intrinsic factor.
- The gastric glands open into the area gastricae.
4. What is not true? In chronic gastritis:
- is there a classification into types A, B and C..
- the diagnosis is primarily made clinically.
- Most patients are symptom free.
- Type A can lead to pernicious anemia.
- is the therapy of type B gastritis in the triple therapy for Helicobacter pylori eradication.
Dual Series Internal Medicine, 2nd edition – Thieme Verlag
Herold, G. and MA. Internal Medicine (2014) – Gerd Herold Verlag
Hofer, Matthias: Sono Basic Course, 7th edition – Thieme Verlag
Lippert: Textbook Anatomy, 8th Edition – Urban & fisherman
Welsch: Textbook Histology, 3rd Edition – Urban & fisherman
Solutions to the questions: 1E, 2D, 3D, 4B
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