Human Stomach

 Human Stomach 

The stomach (from the Latin stomăchus, derived from the Greek στόμαχος [stomachos], from the prefix στόμα [stoma], "mouth") is the portion of the digestive tract located between the esophagus and the intestine. In humans, it is located in the upper left region of the abdomen, below the diaphragm. It is a chamber in which the ingested food is mixed and stored and is emptied in small intervals towards the duodenum thanks to peristaltic movements. Complete gastric emptying requires several hours after a large meal. The stomach is very distensible, so it varies considerably in size depending on whether it is full or empty. It is divided into four main regions, which are called: cardia, which joins it to the esophagus, fundus, body, and pylorus, which connects it to the intestine. It secretes several substances that are collectively called gastric juice, formed mainly by hydrochloric acid and pepsin, a proteolytic enzyme that divides proteins into smaller fragments to facilitate their absorption. In the stomach, food is transformed into a pasty slurry called chyme.


Human Stomach Anatomy


 The size of the stomach is variable depending on its degree of distention; when it is half full it measures on average 25 cm high, 12 cm wide and 8 cm anteroposteriorly.

 The average capacity is around 1200 milliliters (ml).

 It is located in the upper left region of the abdomen, below the diaphragm, its position varies depending on whether the person is standing or lying down.


 The flattened shape of the stomach at rest determines the presence of an anterior face and a posterior face. It also delimits a lesser curvature that extends from the cardia to the pylorus, forming the concave edge of the stomach, and a greater curvature that forms the convex side of the stomach. Its length is four times greater than that of the lesser curvature.


 Anatomically it is divided into several areas: cardio-esophageal, fundus, body (corpus), anthro-pyloric (antrum) due to the macroscopic appearance of its mucosa.


Cardias

The cardia of the stomach is an opening that connects the stomach with the lower portion of the esophagus. It has muscle fibers that help prevent the acid content of the stomach from refluxing into the esophagus.


 Backgroundedit


 The fundus (fundus) is the upper portion of the stomach, close to the cardia.


 Bodyedit


 The body (corpus) is the central or main, largest portion of the stomach that encompasses both curvatures. In this sector are the oxyntic gastric glands that secrete hydrochloric acid.


 Pyloric Antrum


 The pyloric antrum (antrum) is the name of the lower region of the stomach anterior to the pylorus.


 Pylorus


 The Pylorus is located between the stomach and the duodenum. It is a thickening of the muscle fibers of the wall of the digestive tube that forms a sphincter with the purpose of controlling gastric emptying. It is normally in a state of contraction.

The stomach wall is made up of the characteristic layers of the entire digestive tube: mucosa, submucosa, muscular and serosa. The mucosa has cells that produce mucus, hydrochloric acid, and digestive enzymes. The muscular layer consists of longitudinal, circular and oblique fibers. The serosa corresponds to the outermost envelope of the organ.[citation needed]


 Gastric folds


 The mucosa that covers the inner layer of the stomach is not smooth, it has a set of large and elongated longitudinal folds that have the function of multiplying the surface of the mucosa. When the stomach is full, the folds disappear and reappear again when the emptying process takes place. On the inner surface of the folds, there is a set of openings called crypts, gastric pits or foveolae where the gastric glands empty.


 The stomach has fixation systems at its two ends, which are joined by the lesser curvature through the lesser omentum (omentum). At the level of the cardia there is the gastrophrenic ligament at the back, which joins it to the diaphragm. On the pyloric part it is attached to the underside of the liver by the gastrohepatic ligament. These fixation systems determine their relationships with other abdominal organs.


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