About stomach, esophagus and gastric ulcer.

 About stomach, esophagus and gastric ulcer.

Abdominal part of o esophagus : The abdominal part of the o esophagus is only about 1.25 cm long. It enters the abdomen through the oesophageal opening of the diaphragm situated at the level of vertebra T 10, slightly to the left of the median plane. The o esophageal opening also transmits the anterior and posterior gastric nerves, the esophageal branches of the left gastric artery and the accompanying veins. These veins drain partly into portal and partly into systemic circulation. Veins accompanying left gastric vein drain into portal vein. Others drain into heterozygous, in thoracic cavity, and continue into vane zygotes and superior
vane cave. So it is a site of systemically anatomists. The esophagus runs downwards and to the left in front of the left cues of the diaphragm and of the inferior surface of the left lobe of the liver, and ends by opening into the cardiac end of the stomach at the level of vertebra T 11, about 2.5 cm to the left of the median plane. Its right border is continuous with the lesser curvature of the stomach, but the left border  is separated from the fund us of the stomach by the cardiac notch . Peritoneum covers the esophagus only anterior and on the left side. Anterior gastric nerve contains mainly the left Val fibers, and the posterior gastric nerve mainly the right Val fibers.Each gastric nerve is represented by one or two trunks and combines a few sympathetic fibers from the greater splanchnic nerve.

Histology : Mucous membrane - Epithelial lining is stratified squamous nonadministrative in nature. Lamina propriety consists of loose connective tissue with papillae. Muscular is mucosa is distinct in lower part and formed by longitudinal muscle fibers. Sub mucosa contains mucus secreting esophageal glands. Muscular is external is composed is striated muscle in upper third and smooth muscles in lower third. Outer layer comprises longitudinal coat and inner circular coat of muscle fibers. Adventitious is the connective tissue with capillaries.             

Stomach

The stomach is also called the gaiter or center from which we have the adjective gastric applied to structures related to the organ. The caudal part of fore gut shows a fusiform dilatation with anterior and posterior borders and left and right surfaces. This is the stomach. It rotates 90 degree clockwise, so that left surface faces anterior. Even the original posterior border of stomach grows faster, forming the greater curvature. The stomach also rotates along antero posterior axis, so that distal or pyloric part moves to right and proximal or cardiac part moves to left side. The 90 degree rotation of stomach along the vertical axis pulls the dorsal gastronome to the left side creating the lessor sac or o mental bursa. Spleen appears as epidermal condensation in the left leaf of dorsal mesogastrium.    
Definition : The stomach is a muscular bag forming the widest and most extensible part of the digestive tube. It is connected above to the lower end of the o esophagus, and below to the duodenum. It acts as a reservoir of food and helps in digestion of carbohydrates, proteins and fats.
Location : The stomach lies obliquely in the upper and left part of the abdomen, occupying the epigastric, umbilical and left hypochondriac regions. Most of it lies under cover of the left costal margin and the ribs

Shape and position : The shape of the stomach depends upon the degree of its distension and that of the surrounding viscera e.g. the colon. When empty, the stomach is somewhat J - shaped ( vertical ) when partially distended, it becomes pyriform in shape. In obsess persons, it is more horizontal. The shape of the stomach can be studied in the living by radio graphic examination after giving a barium meal
Size : The stomach is a very extensible organ. It is about 25 cm long, and mean capacity is one ounce (30 ml)  at birth, one liter ( 1000 ml ) at puberty, and 1 1/2 to 2 liters or more in adults.

Interior of stomach : The stomach has to be opened to see its internal structure.

1. The mucosa of an empty stomach is thrown into folds termed as gastric rugger are longitudinal along the lesser curvature and are irregular elsewhere. The rugger are flattened in a distended stomach. On the musical surface there are numerous small depressions that can be seen with a hand lens. These are the gastric pits. The part of the lumen of the stomach that lies along the lesser curvature, and has longi - tudinal rugae, is called the gastric canal or magistrate. This canal allows rapid passege of swallowed liquids along the lesser  curvature directly to the lower part before it spreads to the other part of stomach. Thus lesser curvature bears maximum insult of the swallowed liquids,which makes it vulnerable to peptic ulcer.So, beware of your drinks.              
2.Submucous coat is made of connective tissue, arterioles and nerve plexus.
3.Muscle coat is arranged as unger :
( i ).Longitudinal fibres are most superficial, mainly along the curvatures.
( ii ). Inner circular fibres encircle the body and are thickened  at pylorus to form pyloric sphincter.
( iii ). The deepest layer consists of oblique fibers which loop over the cardiac notch. Some fibres spread in the funds and body  of stomach. Rest from a well-developed ridge on each side of the lesser curvature. These fibers on contraction from ''gastric canal'' for the passasge of fluids.
4.Serous coat consists of the peritoneal covering.                      

Cardiac End

Mucous membrane : The epithelium is simple columnar with small tubular glands. Lower half of the gland is secretory and upper half is the conducting part. Muscularis mucosae consists of smooth muscle fibres.
Muscular is membrane : It contains tall simple tubular gastric glands. Upper one-third is conducting , while lower two-thirds is secretory. The various cell types seen in  the gland are chief  or zymogenic, oxyntic or parietal and mucous neck cells.
Mucous membrane : There are pyloric glands which consist of basal one-third as mucus secretory component and upper two thirds  as conducting part. Muscular is external comprises thick layer of circular fibers forming the pyloric sphincter. serosa is same as of cardiac end. Muscular is external comprises thick layer of circular fibers forming the pyloric sphincter. Serosa is same as of cardiac end.

Gastric ulcer

Gastric ulcer occurs typically along the lesser curvature.This is possibly due to the following peculiaritis of lesser curvature.
1.It is homologous with the gastric through of ruminants.
2.Mucosa is not freely movable over the muscular coat.
3.The epithelium is comparatively thin.
4.Blood supply is less abundant and there are fewer anastomoses.
5.Nerve supply is more abundant, with large ganglia.
6.Because of the gastric canal, it receives most of the insult from irritating drinks.
7.Being shorter in length the wave of contraction stays longer at a particular point, viz, the standing wave of incisura.
8.H. pylori infection is also an important causative factor.

Gastric ulcers are common in people who are always in ''hurry'', mostly ''worry'' about incidents and eat ''spicy curry''. Gastric ulcer is notoriously resistant to healing and persists for years together, causing great degree of morbidity. To promote healing the irritating effect of HCL can be minimised by antacids, partial gastrectomy, or vagotomy.

*Gastric carcinoma is common and occurs along the greater curvature.On this account the lymphatic drainage of stomach assumes  importance.Metastasis can occur through the thoracic duct to the left superclavicular lymph nodes are called as ''signal nodes''.
*Pyloric obstruction can be congenital or acquired.It causes visible peristalsis in the epigastrium, and vomiting after meals.
*Hiatal hernia occuring through the oesophageal opening and can be rolling or para-oesophageal and sliding.
*Barrett's oesophagus:Squamous epithelium of lower oesophagus may be replaced by columnar epithelium in certain clinical conditions. The abnormal type of epithelium present in oesophagus is refferd as barrett's epithelium.  
*Tracheo-oesophageal fistula: At times the separation of trachea and o esophagus may not be complete. Proximal segment ends   in a blind pouch and distal segment communicates with trachea.